Files
Varuna Jayasiri 9262c57f18 flash attention
2025-08-08 19:57:57 +05:30

415 lines
54 KiB
HTML

<!DOCTYPE html>
<html lang="en">
<head>
<meta http-equiv="content-type" content="text/html;charset=utf-8"/>
<meta name="viewport" content="width=device-width, initial-scale=1.0"/>
<meta name="description" content=""/>
<meta name="twitter:card" content="summary"/>
<meta name="twitter:image:src" content="https://avatars1.githubusercontent.com/u/64068543?s=400&amp;v=4"/>
<meta name="twitter:title" content="test.py"/>
<meta name="twitter:description" content=""/>
<meta name="twitter:site" content="@labmlai"/>
<meta name="twitter:creator" content="@labmlai"/>
<meta property="og:url" content="https://nn.labml.ai/transformers/flash/test.html"/>
<meta property="og:title" content="test.py"/>
<meta property="og:image" content="https://avatars1.githubusercontent.com/u/64068543?s=400&amp;v=4"/>
<meta property="og:site_name" content="test.py"/>
<meta property="og:type" content="object"/>
<meta property="og:title" content="test.py"/>
<meta property="og:description" content=""/>
<title>test.py</title>
<link rel="shortcut icon" href="/icon.png"/>
<link rel="stylesheet" href="../../pylit.css?v=1">
<link rel="canonical" href="https://nn.labml.ai/transformers/flash/test.html"/>
<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/katex@0.13.18/dist/katex.min.css" integrity="sha384-zTROYFVGOfTw7JV7KUu8udsvW2fx4lWOsCEDqhBreBwlHI4ioVRtmIvEThzJHGET" crossorigin="anonymous">
<!-- Global site tag (gtag.js) - Google Analytics -->
<script async src="https://www.googletagmanager.com/gtag/js?id=G-4V3HC8HBLH"></script>
<script>
window.dataLayer = window.dataLayer || [];
function gtag() {
dataLayer.push(arguments);
}
gtag('js', new Date());
gtag('config', 'G-4V3HC8HBLH');
</script>
</head>
<body>
<div id='container'>
<div id="background"></div>
<div class='section'>
<div class='docs'>
<p>
<a class="parent" href="/">home</a>
<a class="parent" href="../index.html">transformers</a>
<a class="parent" href="index.html">flash</a>
</p>
<p>
<a href="https://github.com/labmlai/annotated_deep_learning_paper_implementations" target="_blank">
<img alt="Github"
src="https://img.shields.io/github/stars/labmlai/annotated_deep_learning_paper_implementations?style=social"
style="max-width:100%;"/></a>
<a href="https://twitter.com/labmlai" rel="nofollow" target="_blank">
<img alt="Twitter"
src="https://img.shields.io/twitter/follow/labmlai?style=social"
style="max-width:100%;"/></a>
</p>
<p>
<a href="https://github.com/labmlai/annotated_deep_learning_paper_implementations/tree/master/labml_nn/transformers/flash/test.py" target="_blank">
View code on Github</a>
</p>
</div>
</div>
<div class='section' id='section-0'>
<div class='docs doc-strings'>
<div class='section-link'>
<a href='#section-0'>#</a>
</div>
<h3>Test Flash Attention Implementation</h3>
<p>This is the code to test and measure performance of our flash attention implementation</p>
</div>
<div class='code'>
<div class="highlight"><pre><span class="lineno">7</span><span></span><span class="kn">import</span> <span class="nn">torch</span>
<span class="lineno">8</span><span class="kn">import</span> <span class="nn">triton</span>
<span class="lineno">9</span>
<span class="lineno">10</span><span class="kn">from</span> <span class="nn">labml</span> <span class="kn">import</span> <span class="n">logger</span><span class="p">,</span> <span class="n">monit</span>
<span class="lineno">11</span><span class="kn">from</span> <span class="nn">labml_nn.transformers.flash</span> <span class="kn">import</span> <span class="n">attention</span>
<span class="lineno">12</span>
<span class="lineno">13</span><span class="n">HI_PRES_TORCH</span> <span class="o">=</span> <span class="n">torch</span><span class="o">.</span><span class="n">float32</span></pre></div>
</div>
</div>
<div class='section' id='section-1'>
<div class='docs doc-strings'>
<div class='section-link'>
<a href='#section-1'>#</a>
</div>
<h4>Calculate absolute and relative error for reporting</h4>
</div>
<div class='code'>
<div class="highlight"><pre><span class="lineno">16</span><span class="nd">@torch</span><span class="o">.</span><span class="n">no_grad</span><span class="p">()</span>
<span class="lineno">17</span><span class="k">def</span> <span class="nf">_calc_abs_rel_error</span><span class="p">(</span><span class="n">a</span><span class="p">:</span> <span class="n">torch</span><span class="o">.</span><span class="n">Tensor</span><span class="p">,</span> <span class="n">b</span><span class="p">:</span> <span class="n">torch</span><span class="o">.</span><span class="n">Tensor</span><span class="p">,</span> <span class="n">atol</span><span class="o">=</span><span class="mf">1e-2</span><span class="p">):</span></pre></div>
</div>
</div>
<div class='section' id='section-2'>
<div class='docs'>
<div class='section-link'>
<a href='#section-2'>#</a>
</div>
</div>
<div class='code'>
<div class="highlight"><pre><span class="lineno">21</span> <span class="n">d</span> <span class="o">=</span> <span class="p">(</span><span class="n">a</span> <span class="o">-</span> <span class="n">b</span><span class="p">)</span><span class="o">.</span><span class="n">abs</span><span class="p">()</span>
<span class="lineno">22</span> <span class="n">max_abs</span> <span class="o">=</span> <span class="n">d</span><span class="o">.</span><span class="n">max</span><span class="p">()</span>
<span class="lineno">23</span> <span class="n">d</span> <span class="o">=</span> <span class="p">(</span><span class="n">d</span> <span class="o">-</span> <span class="n">atol</span><span class="p">)</span><span class="o">.</span><span class="n">clamp</span><span class="p">(</span><span class="nb">min</span><span class="o">=</span><span class="mi">0</span><span class="p">)</span>
<span class="lineno">24</span> <span class="n">d</span> <span class="o">=</span> <span class="n">d</span> <span class="o">/</span> <span class="n">b</span><span class="o">.</span><span class="n">abs</span><span class="p">()</span>
<span class="lineno">25</span> <span class="n">max_rel</span> <span class="o">=</span> <span class="n">d</span><span class="o">.</span><span class="n">max</span><span class="p">()</span>
<span class="lineno">26</span>
<span class="lineno">27</span> <span class="k">return</span> <span class="n">max_abs</span><span class="o">.</span><span class="n">cpu</span><span class="p">()</span><span class="o">.</span><span class="n">item</span><span class="p">(),</span> <span class="n">max_rel</span><span class="o">.</span><span class="n">cpu</span><span class="p">()</span><span class="o">.</span><span class="n">item</span><span class="p">()</span></pre></div>
</div>
</div>
<div class='section' id='section-3'>
<div class='docs doc-strings'>
<div class='section-link'>
<a href='#section-3'>#</a>
</div>
<h4>Compare our implementation with naive PyTorch attention</h4>
</div>
<div class='code'>
<div class="highlight"><pre><span class="lineno">30</span><span class="k">def</span> <span class="nf">test_fwd_bwd</span><span class="p">(</span><span class="n">batch_size</span><span class="p">,</span> <span class="n">n_heads</span><span class="p">,</span> <span class="n">k_heads</span><span class="p">,</span> <span class="n">q_seq_len</span><span class="p">,</span> <span class="n">kv_seq_len</span><span class="p">,</span> <span class="n">d_head</span><span class="p">,</span> <span class="n">causal</span><span class="p">,</span> <span class="n">dtype</span><span class="p">,</span> <span class="n">device</span><span class="p">):</span></pre></div>
</div>
</div>
<div class='section' id='section-4'>
<div class='docs'>
<div class='section-link'>
<a href='#section-4'>#</a>
</div>
</div>
<div class='code'>
<div class="highlight"><pre><span class="lineno">35</span> <span class="k">with</span> <span class="n">monit</span><span class="o">.</span><span class="n">section</span><span class="p">(</span><span class="sa">f</span><span class="s1">&#39;Init </span><span class="si">{</span><span class="n">q_seq_len</span><span class="si">}</span><span class="s1"> </span><span class="si">{</span><span class="n">kv_seq_len</span><span class="si">}</span><span class="s1"> </span><span class="si">{</span><span class="n">d_head</span><span class="si">}</span><span class="s1">&#39;</span><span class="p">):</span>
<span class="lineno">36</span> <span class="n">torch</span><span class="o">.</span><span class="n">manual_seed</span><span class="p">(</span><span class="mi">20</span><span class="p">)</span>
<span class="lineno">37</span> <span class="n">q</span> <span class="o">=</span> <span class="p">(</span><span class="n">torch</span><span class="o">.</span><span class="n">empty</span><span class="p">((</span><span class="n">batch_size</span><span class="p">,</span> <span class="n">n_heads</span><span class="p">,</span> <span class="n">q_seq_len</span><span class="p">,</span> <span class="n">d_head</span><span class="p">),</span>
<span class="lineno">38</span> <span class="n">dtype</span><span class="o">=</span><span class="n">dtype</span><span class="p">,</span> <span class="n">device</span><span class="o">=</span><span class="n">device</span><span class="p">)</span><span class="o">.</span><span class="n">normal_</span><span class="p">(</span><span class="n">mean</span><span class="o">=</span><span class="mf">0.0</span><span class="p">,</span> <span class="n">std</span><span class="o">=</span><span class="mf">0.5</span><span class="p">)</span><span class="o">.</span><span class="n">requires_grad_</span><span class="p">())</span>
<span class="lineno">39</span> <span class="n">k</span> <span class="o">=</span> <span class="p">(</span><span class="n">torch</span><span class="o">.</span><span class="n">empty</span><span class="p">((</span><span class="n">batch_size</span><span class="p">,</span> <span class="n">k_heads</span><span class="p">,</span> <span class="n">kv_seq_len</span><span class="p">,</span> <span class="n">d_head</span><span class="p">),</span>
<span class="lineno">40</span> <span class="n">dtype</span><span class="o">=</span><span class="n">dtype</span><span class="p">,</span> <span class="n">device</span><span class="o">=</span><span class="n">device</span><span class="p">)</span><span class="o">.</span><span class="n">normal_</span><span class="p">(</span><span class="n">mean</span><span class="o">=</span><span class="mf">0.0</span><span class="p">,</span> <span class="n">std</span><span class="o">=</span><span class="mf">0.5</span><span class="p">)</span><span class="o">.</span><span class="n">requires_grad_</span><span class="p">())</span>
<span class="lineno">41</span> <span class="n">v</span> <span class="o">=</span> <span class="p">(</span><span class="n">torch</span><span class="o">.</span><span class="n">empty</span><span class="p">((</span><span class="n">batch_size</span><span class="p">,</span> <span class="n">k_heads</span><span class="p">,</span> <span class="n">kv_seq_len</span><span class="p">,</span> <span class="n">d_head</span><span class="p">),</span>
<span class="lineno">42</span> <span class="n">dtype</span><span class="o">=</span><span class="n">dtype</span><span class="p">,</span> <span class="n">device</span><span class="o">=</span><span class="n">device</span><span class="p">)</span><span class="o">.</span><span class="n">normal_</span><span class="p">(</span><span class="n">mean</span><span class="o">=</span><span class="mf">0.0</span><span class="p">,</span> <span class="n">std</span><span class="o">=</span><span class="mf">0.5</span><span class="p">)</span><span class="o">.</span><span class="n">requires_grad_</span><span class="p">())</span>
<span class="lineno">43</span> <span class="n">sm_scale</span> <span class="o">=</span> <span class="n">d_head</span> <span class="o">**</span> <span class="o">-</span><span class="mf">0.5</span>
<span class="lineno">44</span> <span class="n">d_out</span> <span class="o">=</span> <span class="n">torch</span><span class="o">.</span><span class="n">randn_like</span><span class="p">(</span><span class="n">q</span><span class="p">)</span></pre></div>
</div>
</div>
<div class='section' id='section-5'>
<div class='docs'>
<div class='section-link'>
<a href='#section-5'>#</a>
</div>
<p>reference implementation </p>
</div>
<div class='code'>
<div class="highlight"><pre><span class="lineno">46</span> <span class="n">mask</span> <span class="o">=</span> <span class="n">torch</span><span class="o">.</span><span class="n">tril</span><span class="p">(</span><span class="n">torch</span><span class="o">.</span><span class="n">ones</span><span class="p">((</span><span class="n">q_seq_len</span><span class="p">,</span> <span class="n">kv_seq_len</span><span class="p">),</span> <span class="n">device</span><span class="o">=</span><span class="n">device</span><span class="p">,</span> <span class="n">dtype</span><span class="o">=</span><span class="n">torch</span><span class="o">.</span><span class="n">bool</span><span class="p">))</span>
<span class="lineno">47</span> <span class="n">torch</span><span class="o">.</span><span class="n">cuda</span><span class="o">.</span><span class="n">synchronize</span><span class="p">()</span>
<span class="lineno">48</span>
<span class="lineno">49</span> <span class="k">with</span> <span class="n">monit</span><span class="o">.</span><span class="n">section</span><span class="p">(</span><span class="s1">&#39;Pytorch&#39;</span><span class="p">):</span>
<span class="lineno">50</span> <span class="n">p</span> <span class="o">=</span> <span class="n">torch</span><span class="o">.</span><span class="n">matmul</span><span class="p">(</span><span class="n">q</span><span class="o">.</span><span class="n">view</span><span class="p">(</span><span class="n">batch_size</span><span class="p">,</span> <span class="n">k_heads</span><span class="p">,</span> <span class="o">-</span><span class="mi">1</span><span class="p">,</span> <span class="n">q_seq_len</span><span class="p">,</span> <span class="n">d_head</span><span class="p">),</span>
<span class="lineno">51</span> <span class="n">k</span><span class="o">.</span><span class="n">transpose</span><span class="p">(</span><span class="mi">2</span><span class="p">,</span> <span class="mi">3</span><span class="p">)[:,</span> <span class="p">:,</span> <span class="kc">None</span><span class="p">,</span> <span class="p">:,</span> <span class="p">:])</span> <span class="o">*</span> <span class="n">sm_scale</span>
<span class="lineno">52</span> <span class="k">if</span> <span class="n">causal</span><span class="p">:</span>
<span class="lineno">53</span> <span class="n">p</span><span class="p">[:,</span> <span class="p">:,</span> <span class="p">:,</span> <span class="o">~</span><span class="n">mask</span><span class="p">]</span> <span class="o">=</span> <span class="nb">float</span><span class="p">(</span><span class="s2">&quot;-inf&quot;</span><span class="p">)</span>
<span class="lineno">54</span> <span class="n">p</span> <span class="o">=</span> <span class="n">torch</span><span class="o">.</span><span class="n">softmax</span><span class="p">(</span><span class="n">p</span><span class="o">.</span><span class="n">to</span><span class="p">(</span><span class="n">HI_PRES_TORCH</span><span class="p">),</span> <span class="n">dim</span><span class="o">=-</span><span class="mi">1</span><span class="p">)</span><span class="o">.</span><span class="n">to</span><span class="p">(</span><span class="n">dtype</span><span class="p">)</span>
<span class="lineno">55</span> <span class="n">ref_out</span> <span class="o">=</span> <span class="n">torch</span><span class="o">.</span><span class="n">matmul</span><span class="p">(</span><span class="n">p</span><span class="p">,</span> <span class="n">v</span><span class="p">[:,</span> <span class="p">:,</span> <span class="kc">None</span><span class="p">,</span> <span class="p">:,</span> <span class="p">:])</span>
<span class="lineno">56</span> <span class="n">ref_out</span> <span class="o">=</span> <span class="n">ref_out</span><span class="o">.</span><span class="n">view</span><span class="p">(</span><span class="n">q</span><span class="o">.</span><span class="n">shape</span><span class="p">)</span>
<span class="lineno">57</span> <span class="n">ref_out</span><span class="o">.</span><span class="n">backward</span><span class="p">(</span><span class="n">d_out</span><span class="p">)</span>
<span class="lineno">58</span> <span class="n">ref_dv</span><span class="p">,</span> <span class="n">v</span><span class="o">.</span><span class="n">grad</span> <span class="o">=</span> <span class="n">v</span><span class="o">.</span><span class="n">grad</span><span class="o">.</span><span class="n">clone</span><span class="p">(),</span> <span class="kc">None</span>
<span class="lineno">59</span> <span class="n">ref_dk</span><span class="p">,</span> <span class="n">k</span><span class="o">.</span><span class="n">grad</span> <span class="o">=</span> <span class="n">k</span><span class="o">.</span><span class="n">grad</span><span class="o">.</span><span class="n">clone</span><span class="p">(),</span> <span class="kc">None</span>
<span class="lineno">60</span> <span class="n">ref_dq</span><span class="p">,</span> <span class="n">q</span><span class="o">.</span><span class="n">grad</span> <span class="o">=</span> <span class="n">q</span><span class="o">.</span><span class="n">grad</span><span class="o">.</span><span class="n">clone</span><span class="p">(),</span> <span class="kc">None</span>
<span class="lineno">61</span> <span class="n">torch</span><span class="o">.</span><span class="n">cuda</span><span class="o">.</span><span class="n">synchronize</span><span class="p">()</span>
<span class="lineno">62</span>
<span class="lineno">63</span> <span class="k">with</span> <span class="n">monit</span><span class="o">.</span><span class="n">section</span><span class="p">(</span><span class="s1">&#39;Triton&#39;</span><span class="p">):</span>
<span class="lineno">64</span> <span class="k">assert</span> <span class="n">q</span><span class="o">.</span><span class="n">dtype</span> <span class="o">==</span> <span class="n">dtype</span>
<span class="lineno">65</span> <span class="n">tri_out</span> <span class="o">=</span> <span class="n">attention</span><span class="p">(</span><span class="n">q</span><span class="p">,</span> <span class="n">k</span><span class="p">,</span> <span class="n">v</span><span class="p">,</span> <span class="n">causal</span><span class="p">,</span> <span class="n">sm_scale</span><span class="p">)</span><span class="o">.</span><span class="n">to</span><span class="p">(</span><span class="n">dtype</span><span class="p">)</span>
<span class="lineno">66</span> <span class="n">monit</span><span class="o">.</span><span class="n">progress</span><span class="p">(</span><span class="mf">0.5</span><span class="p">)</span>
<span class="lineno">67</span>
<span class="lineno">68</span> <span class="n">tri_out</span><span class="o">.</span><span class="n">backward</span><span class="p">(</span><span class="n">d_out</span><span class="p">)</span>
<span class="lineno">69</span> <span class="n">monit</span><span class="o">.</span><span class="n">progress</span><span class="p">(</span><span class="mf">0.9</span><span class="p">)</span>
<span class="lineno">70</span> <span class="n">tri_dv</span><span class="p">,</span> <span class="n">v</span><span class="o">.</span><span class="n">grad</span> <span class="o">=</span> <span class="n">v</span><span class="o">.</span><span class="n">grad</span><span class="o">.</span><span class="n">clone</span><span class="p">(),</span> <span class="kc">None</span> <span class="c1"># type: ignore</span>
<span class="lineno">71</span> <span class="n">tri_dk</span><span class="p">,</span> <span class="n">k</span><span class="o">.</span><span class="n">grad</span> <span class="o">=</span> <span class="n">k</span><span class="o">.</span><span class="n">grad</span><span class="o">.</span><span class="n">clone</span><span class="p">(),</span> <span class="kc">None</span> <span class="c1"># type: ignore</span>
<span class="lineno">72</span> <span class="n">tri_dq</span><span class="p">,</span> <span class="n">q</span><span class="o">.</span><span class="n">grad</span> <span class="o">=</span> <span class="n">q</span><span class="o">.</span><span class="n">grad</span><span class="o">.</span><span class="n">clone</span><span class="p">(),</span> <span class="kc">None</span> <span class="c1"># type: ignore</span>
<span class="lineno">73</span> <span class="n">torch</span><span class="o">.</span><span class="n">cuda</span><span class="o">.</span><span class="n">synchronize</span><span class="p">()</span>
<span class="lineno">74</span>
<span class="lineno">75</span> <span class="k">with</span> <span class="n">monit</span><span class="o">.</span><span class="n">section</span><span class="p">(</span><span class="s1">&#39;Test&#39;</span><span class="p">)</span> <span class="k">as</span> <span class="n">s</span><span class="p">:</span></pre></div>
</div>
</div>
<div class='section' id='section-6'>
<div class='docs'>
<div class='section-link'>
<a href='#section-6'>#</a>
</div>
<p>compare </p>
</div>
<div class='code'>
<div class="highlight"><pre><span class="lineno">77</span> <span class="n">passed</span> <span class="o">=</span> <span class="kc">True</span>
<span class="lineno">78</span> <span class="k">if</span> <span class="ow">not</span> <span class="n">torch</span><span class="o">.</span><span class="n">allclose</span><span class="p">(</span><span class="n">tri_out</span><span class="p">,</span> <span class="n">ref_out</span><span class="p">,</span> <span class="n">atol</span><span class="o">=</span><span class="mf">1e-2</span><span class="p">,</span> <span class="n">rtol</span><span class="o">=</span><span class="mf">0.</span><span class="p">):</span>
<span class="lineno">79</span> <span class="n">abs_err</span><span class="p">,</span> <span class="n">rel_err</span> <span class="o">=</span> <span class="n">_calc_abs_rel_error</span><span class="p">(</span><span class="n">ref_out</span><span class="p">,</span> <span class="n">tri_out</span><span class="p">)</span>
<span class="lineno">80</span> <span class="n">logger</span><span class="o">.</span><span class="n">log</span><span class="p">((</span><span class="s1">&#39;[FAILED]&#39;</span><span class="p">,</span> <span class="n">logger</span><span class="o">.</span><span class="n">Text</span><span class="o">.</span><span class="n">danger</span><span class="p">),</span> <span class="sa">f</span><span class="s1">&#39; Out mismatch </span><span class="si">{</span><span class="n">abs_err</span><span class="si">}</span><span class="s1"> </span><span class="si">{</span><span class="n">rel_err</span><span class="si">}</span><span class="s1">&#39;</span><span class="p">)</span>
<span class="lineno">81</span> <span class="n">passed</span> <span class="o">=</span> <span class="kc">False</span>
<span class="lineno">82</span> <span class="n">rtol</span> <span class="o">=</span> <span class="mf">1e-1</span>
<span class="lineno">83</span> <span class="k">if</span> <span class="ow">not</span> <span class="n">torch</span><span class="o">.</span><span class="n">allclose</span><span class="p">(</span><span class="n">tri_dq</span><span class="p">,</span> <span class="n">ref_dq</span><span class="p">,</span> <span class="n">atol</span><span class="o">=</span><span class="mf">1e-2</span><span class="p">,</span> <span class="n">rtol</span><span class="o">=</span><span class="n">rtol</span><span class="p">):</span>
<span class="lineno">84</span> <span class="n">abs_err</span><span class="p">,</span> <span class="n">rel_err</span> <span class="o">=</span> <span class="n">_calc_abs_rel_error</span><span class="p">(</span><span class="n">ref_dq</span><span class="p">,</span> <span class="n">tri_dq</span><span class="p">)</span>
<span class="lineno">85</span> <span class="n">logger</span><span class="o">.</span><span class="n">log</span><span class="p">((</span><span class="s1">&#39;[FAILED]&#39;</span><span class="p">,</span> <span class="n">logger</span><span class="o">.</span><span class="n">Text</span><span class="o">.</span><span class="n">danger</span><span class="p">),</span> <span class="sa">f</span><span class="s1">&#39; dQ mismatch </span><span class="si">{</span><span class="n">abs_err</span><span class="si">}</span><span class="s1"> </span><span class="si">{</span><span class="n">rel_err</span><span class="si">}</span><span class="s1">&#39;</span><span class="p">)</span>
<span class="lineno">86</span> <span class="n">passed</span> <span class="o">=</span> <span class="kc">False</span>
<span class="lineno">87</span> <span class="k">if</span> <span class="ow">not</span> <span class="n">torch</span><span class="o">.</span><span class="n">allclose</span><span class="p">(</span><span class="n">tri_dv</span><span class="p">,</span> <span class="n">ref_dv</span><span class="p">,</span> <span class="n">atol</span><span class="o">=</span><span class="mf">1e-2</span><span class="p">,</span> <span class="n">rtol</span><span class="o">=</span><span class="n">rtol</span><span class="p">):</span>
<span class="lineno">88</span> <span class="n">abs_err</span><span class="p">,</span> <span class="n">rel_err</span> <span class="o">=</span> <span class="n">_calc_abs_rel_error</span><span class="p">(</span><span class="n">ref_dv</span><span class="p">,</span> <span class="n">tri_dv</span><span class="p">)</span>
<span class="lineno">89</span> <span class="n">logger</span><span class="o">.</span><span class="n">log</span><span class="p">((</span><span class="s1">&#39;[FAILED]&#39;</span><span class="p">,</span> <span class="n">logger</span><span class="o">.</span><span class="n">Text</span><span class="o">.</span><span class="n">danger</span><span class="p">),</span> <span class="sa">f</span><span class="s1">&#39; dV mismatch </span><span class="si">{</span><span class="n">abs_err</span><span class="si">}</span><span class="s1"> </span><span class="si">{</span><span class="n">rel_err</span><span class="si">}</span><span class="s1">&#39;</span><span class="p">)</span>
<span class="lineno">90</span> <span class="n">passed</span> <span class="o">=</span> <span class="kc">False</span>
<span class="lineno">91</span> <span class="k">if</span> <span class="ow">not</span> <span class="n">torch</span><span class="o">.</span><span class="n">allclose</span><span class="p">(</span><span class="n">tri_dk</span><span class="p">,</span> <span class="n">ref_dk</span><span class="p">,</span> <span class="n">atol</span><span class="o">=</span><span class="mf">1e-2</span><span class="p">,</span> <span class="n">rtol</span><span class="o">=</span><span class="n">rtol</span><span class="p">):</span>
<span class="lineno">92</span> <span class="n">abs_err</span><span class="p">,</span> <span class="n">rel_err</span> <span class="o">=</span> <span class="n">_calc_abs_rel_error</span><span class="p">(</span><span class="n">ref_dk</span><span class="p">,</span> <span class="n">tri_dk</span><span class="p">)</span>
<span class="lineno">93</span> <span class="n">logger</span><span class="o">.</span><span class="n">log</span><span class="p">((</span><span class="s1">&#39;[FAILED]&#39;</span><span class="p">,</span> <span class="n">logger</span><span class="o">.</span><span class="n">Text</span><span class="o">.</span><span class="n">danger</span><span class="p">),</span> <span class="sa">f</span><span class="s1">&#39; dK mismatch </span><span class="si">{</span><span class="n">abs_err</span><span class="si">}</span><span class="s1"> </span><span class="si">{</span><span class="n">rel_err</span><span class="si">}</span><span class="s1">&#39;</span><span class="p">)</span>
<span class="lineno">94</span> <span class="n">passed</span> <span class="o">=</span> <span class="kc">False</span>
<span class="lineno">95</span>
<span class="lineno">96</span> <span class="k">if</span> <span class="n">passed</span><span class="p">:</span>
<span class="lineno">97</span> <span class="n">logger</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s1">&#39;[PASSED]&#39;</span><span class="p">,</span> <span class="n">logger</span><span class="o">.</span><span class="n">Text</span><span class="o">.</span><span class="n">success</span><span class="p">)</span>
<span class="lineno">98</span> <span class="n">s</span><span class="o">.</span><span class="n">success</span> <span class="o">=</span> <span class="kc">True</span>
<span class="lineno">99</span> <span class="k">else</span><span class="p">:</span>
<span class="lineno">100</span> <span class="n">s</span><span class="o">.</span><span class="n">success</span> <span class="o">=</span> <span class="kc">False</span>
<span class="lineno">101</span> <span class="n">torch</span><span class="o">.</span><span class="n">cuda</span><span class="o">.</span><span class="n">synchronize</span><span class="p">()</span></pre></div>
</div>
</div>
<div class='section' id='section-7'>
<div class='docs doc-strings'>
<div class='section-link'>
<a href='#section-7'>#</a>
</div>
<p> Get a partial function to test performance of our implementation</p>
</div>
<div class='code'>
<div class="highlight"><pre><span class="lineno">104</span><span class="k">def</span> <span class="nf">_perf_triton_fn</span><span class="p">(</span><span class="o">*</span><span class="p">,</span> <span class="n">device</span><span class="p">,</span> <span class="n">dtype</span><span class="p">,</span> <span class="n">batch_size</span><span class="p">,</span> <span class="n">k_heads</span><span class="p">,</span> <span class="n">n_groups</span><span class="p">,</span> <span class="n">seq_len</span><span class="p">,</span> <span class="n">d_head</span><span class="p">,</span> <span class="n">causal</span><span class="p">):</span></pre></div>
</div>
</div>
<div class='section' id='section-8'>
<div class='docs'>
<div class='section-link'>
<a href='#section-8'>#</a>
</div>
</div>
<div class='code'>
<div class="highlight"><pre><span class="lineno">108</span> <span class="n">q</span> <span class="o">=</span> <span class="n">torch</span><span class="o">.</span><span class="n">randn</span><span class="p">((</span><span class="n">batch_size</span><span class="p">,</span> <span class="n">k_heads</span> <span class="o">*</span> <span class="n">n_groups</span><span class="p">,</span> <span class="n">seq_len</span><span class="p">,</span> <span class="n">d_head</span><span class="p">),</span> <span class="n">dtype</span><span class="o">=</span><span class="n">dtype</span><span class="p">,</span> <span class="n">device</span><span class="o">=</span><span class="n">device</span><span class="p">,</span> <span class="n">requires_grad</span><span class="o">=</span><span class="kc">True</span><span class="p">)</span>
<span class="lineno">109</span> <span class="n">k</span> <span class="o">=</span> <span class="n">torch</span><span class="o">.</span><span class="n">randn</span><span class="p">((</span><span class="n">batch_size</span><span class="p">,</span> <span class="n">k_heads</span><span class="p">,</span> <span class="n">seq_len</span><span class="p">,</span> <span class="n">d_head</span><span class="p">),</span> <span class="n">dtype</span><span class="o">=</span><span class="n">dtype</span><span class="p">,</span> <span class="n">device</span><span class="o">=</span><span class="n">device</span><span class="p">,</span> <span class="n">requires_grad</span><span class="o">=</span><span class="kc">True</span><span class="p">)</span>
<span class="lineno">110</span> <span class="n">v</span> <span class="o">=</span> <span class="n">torch</span><span class="o">.</span><span class="n">randn</span><span class="p">((</span><span class="n">batch_size</span><span class="p">,</span> <span class="n">k_heads</span><span class="p">,</span> <span class="n">seq_len</span><span class="p">,</span> <span class="n">d_head</span><span class="p">),</span> <span class="n">dtype</span><span class="o">=</span><span class="n">dtype</span><span class="p">,</span> <span class="n">device</span><span class="o">=</span><span class="n">device</span><span class="p">,</span> <span class="n">requires_grad</span><span class="o">=</span><span class="kc">True</span><span class="p">)</span>
<span class="lineno">111</span> <span class="n">sm_scale</span> <span class="o">=</span> <span class="n">d_head</span> <span class="o">**</span> <span class="o">-</span><span class="mf">0.5</span>
<span class="lineno">112</span> <span class="k">return</span> <span class="k">lambda</span><span class="p">:</span> <span class="n">attention</span><span class="p">(</span><span class="n">q</span><span class="p">,</span> <span class="n">k</span><span class="p">,</span> <span class="n">v</span><span class="p">,</span> <span class="n">causal</span><span class="p">,</span> <span class="n">sm_scale</span><span class="p">)</span></pre></div>
</div>
</div>
<div class='section' id='section-9'>
<div class='docs doc-strings'>
<div class='section-link'>
<a href='#section-9'>#</a>
</div>
<p> Get a partial function to test performance of original flash implementation</p>
</div>
<div class='code'>
<div class="highlight"><pre><span class="lineno">115</span><span class="k">def</span> <span class="nf">_perf_flash</span><span class="p">(</span><span class="o">*</span><span class="p">,</span> <span class="n">batch_size</span><span class="p">,</span> <span class="n">k_heads</span><span class="p">,</span> <span class="n">n_groups</span><span class="p">,</span> <span class="n">seq_len</span><span class="p">,</span> <span class="n">d_head</span><span class="p">,</span> <span class="n">causal</span><span class="p">,</span> <span class="n">device</span><span class="p">,</span> <span class="n">dtype</span><span class="p">):</span></pre></div>
</div>
</div>
<div class='section' id='section-10'>
<div class='docs'>
<div class='section-link'>
<a href='#section-10'>#</a>
</div>
</div>
<div class='code'>
<div class="highlight"><pre><span class="lineno">119</span> <span class="n">q</span> <span class="o">=</span> <span class="n">torch</span><span class="o">.</span><span class="n">randn</span><span class="p">((</span><span class="n">batch_size</span><span class="p">,</span> <span class="n">seq_len</span><span class="p">,</span> <span class="n">k_heads</span> <span class="o">*</span> <span class="n">n_groups</span><span class="p">,</span> <span class="n">d_head</span><span class="p">),</span> <span class="n">dtype</span><span class="o">=</span><span class="n">dtype</span><span class="p">,</span> <span class="n">device</span><span class="o">=</span><span class="n">device</span><span class="p">,</span> <span class="n">requires_grad</span><span class="o">=</span><span class="kc">True</span><span class="p">)</span>
<span class="lineno">120</span> <span class="n">k</span> <span class="o">=</span> <span class="n">torch</span><span class="o">.</span><span class="n">randn</span><span class="p">((</span><span class="n">batch_size</span><span class="p">,</span> <span class="n">seq_len</span><span class="p">,</span> <span class="n">k_heads</span><span class="p">,</span> <span class="n">d_head</span><span class="p">),</span> <span class="n">dtype</span><span class="o">=</span><span class="n">dtype</span><span class="p">,</span> <span class="n">device</span><span class="o">=</span><span class="n">device</span><span class="p">,</span> <span class="n">requires_grad</span><span class="o">=</span><span class="kc">True</span><span class="p">)</span>
<span class="lineno">121</span> <span class="n">v</span> <span class="o">=</span> <span class="n">torch</span><span class="o">.</span><span class="n">randn</span><span class="p">((</span><span class="n">batch_size</span><span class="p">,</span> <span class="n">seq_len</span><span class="p">,</span> <span class="n">k_heads</span><span class="p">,</span> <span class="n">d_head</span><span class="p">),</span> <span class="n">dtype</span><span class="o">=</span><span class="n">dtype</span><span class="p">,</span> <span class="n">device</span><span class="o">=</span><span class="n">device</span><span class="p">,</span> <span class="n">requires_grad</span><span class="o">=</span><span class="kc">True</span><span class="p">)</span>
<span class="lineno">122</span> <span class="kn">from</span> <span class="nn">flash_attn</span> <span class="kn">import</span> <span class="n">flash_attn_func</span>
<span class="lineno">123</span> <span class="k">return</span> <span class="k">lambda</span><span class="p">:</span> <span class="n">flash_attn_func</span><span class="p">(</span><span class="n">q</span><span class="p">,</span> <span class="n">k</span><span class="p">,</span> <span class="n">v</span><span class="p">,</span> <span class="n">causal</span><span class="o">=</span><span class="n">causal</span><span class="p">)</span></pre></div>
</div>
</div>
<div class='section' id='section-11'>
<div class='docs doc-strings'>
<div class='section-link'>
<a href='#section-11'>#</a>
</div>
<h3>Measure the speed</h3>
</div>
<div class='code'>
<div class="highlight"><pre><span class="lineno">126</span><span class="k">def</span> <span class="nf">measure_performance</span><span class="p">(</span><span class="n">name</span><span class="p">,</span> <span class="n">fn</span><span class="p">,</span> <span class="o">*</span><span class="p">,</span> <span class="n">batch_size</span><span class="p">,</span> <span class="n">k_heads</span><span class="p">,</span> <span class="n">n_groups</span><span class="p">,</span> <span class="n">seq_len</span><span class="p">,</span> <span class="n">d_head</span><span class="p">,</span> <span class="n">causal</span><span class="p">,</span> <span class="n">is_bwd</span><span class="p">:</span> <span class="nb">bool</span><span class="p">):</span></pre></div>
</div>
</div>
<div class='section' id='section-12'>
<div class='docs'>
<div class='section-link'>
<a href='#section-12'>#</a>
</div>
</div>
<div class='code'>
<div class="highlight"><pre><span class="lineno">130</span> <span class="k">if</span> <span class="n">is_bwd</span><span class="p">:</span>
<span class="lineno">131</span> <span class="n">o</span> <span class="o">=</span> <span class="n">fn</span><span class="p">()</span>
<span class="lineno">132</span> <span class="n">do</span> <span class="o">=</span> <span class="n">torch</span><span class="o">.</span><span class="n">randn_like</span><span class="p">(</span><span class="n">o</span><span class="p">)</span>
<span class="lineno">133</span> <span class="n">fn</span> <span class="o">=</span> <span class="k">lambda</span><span class="p">:</span> <span class="n">o</span><span class="o">.</span><span class="n">backward</span><span class="p">(</span><span class="n">do</span><span class="p">,</span> <span class="n">retain_graph</span><span class="o">=</span><span class="kc">True</span><span class="p">)</span>
<span class="lineno">134</span> <span class="n">ms</span> <span class="o">=</span> <span class="n">triton</span><span class="o">.</span><span class="n">testing</span><span class="o">.</span><span class="n">do_bench</span><span class="p">(</span><span class="n">fn</span><span class="p">)</span>
<span class="lineno">135</span>
<span class="lineno">136</span> <span class="n">flops_per_matmul</span> <span class="o">=</span> <span class="mf">2.0</span> <span class="o">*</span> <span class="n">batch_size</span> <span class="o">*</span> <span class="n">k_heads</span> <span class="o">*</span> <span class="n">n_groups</span> <span class="o">*</span> <span class="n">seq_len</span> <span class="o">*</span> <span class="n">seq_len</span> <span class="o">*</span> <span class="n">d_head</span>
<span class="lineno">137</span> <span class="n">total_flops</span> <span class="o">=</span> <span class="mi">2</span> <span class="o">*</span> <span class="n">flops_per_matmul</span>
<span class="lineno">138</span> <span class="k">if</span> <span class="n">causal</span><span class="p">:</span>
<span class="lineno">139</span> <span class="n">total_flops</span> <span class="o">*=</span> <span class="mf">0.5</span>
<span class="lineno">140</span> <span class="k">if</span> <span class="n">is_bwd</span><span class="p">:</span>
<span class="lineno">141</span> <span class="n">total_flops</span> <span class="o">*=</span> <span class="mf">2.5</span> <span class="c1"># 2.0(bwd) + 0.5(recompute)</span>
<span class="lineno">142</span>
<span class="lineno">143</span> <span class="n">tf_ps</span> <span class="o">=</span> <span class="n">total_flops</span> <span class="o">*</span> <span class="mf">1e-12</span> <span class="o">/</span> <span class="p">(</span><span class="n">ms</span> <span class="o">*</span> <span class="mf">1e-3</span><span class="p">)</span>
<span class="lineno">144</span> <span class="n">logger</span><span class="o">.</span><span class="n">log</span><span class="p">((</span><span class="sa">f</span><span class="s1">&#39;</span><span class="si">{</span><span class="n">name</span><span class="si">}</span><span class="s1">&#39;</span><span class="p">,</span> <span class="n">logger</span><span class="o">.</span><span class="n">Text</span><span class="o">.</span><span class="n">key</span><span class="p">),</span> <span class="s1">&#39;: &#39;</span><span class="p">,</span> <span class="sa">f</span><span class="s1">&#39;</span><span class="si">{</span><span class="n">ms</span><span class="w"> </span><span class="si">:</span><span class="s1">,.1f</span><span class="si">}</span><span class="s1">ms&#39;</span><span class="p">,</span> <span class="s1">&#39; &#39;</span><span class="p">,</span> <span class="sa">f</span><span class="s1">&#39;</span><span class="si">{</span><span class="n">tf_ps</span><span class="w"> </span><span class="si">:</span><span class="s1">,.2f</span><span class="si">}</span><span class="s1">TFps&#39;</span><span class="p">)</span></pre></div>
</div>
</div>
<div class='section' id='section-13'>
<div class='docs'>
<div class='section-link'>
<a href='#section-13'>#</a>
</div>
</div>
<div class='code'>
<div class="highlight"><pre><span class="lineno">147</span><span class="k">def</span> <span class="nf">main</span><span class="p">():</span>
<span class="lineno">148</span> <span class="n">device</span> <span class="o">=</span> <span class="n">torch</span><span class="o">.</span><span class="n">device</span><span class="p">(</span><span class="s1">&#39;cuda:0&#39;</span><span class="p">)</span>
<span class="lineno">149</span> <span class="n">torch</span><span class="o">.</span><span class="n">cuda</span><span class="o">.</span><span class="n">set_device</span><span class="p">(</span><span class="n">device</span><span class="p">)</span>
<span class="lineno">150</span>
<span class="lineno">151</span> <span class="n">dtype</span> <span class="o">=</span> <span class="n">torch</span><span class="o">.</span><span class="n">float16</span></pre></div>
</div>
</div>
<div class='section' id='section-14'>
<div class='docs'>
<div class='section-link'>
<a href='#section-14'>#</a>
</div>
<p>only works on post-Ampere GPUs right now </p>
</div>
<div class='code'>
<div class="highlight"><pre><span class="lineno">154</span> <span class="n">test_fwd_bwd</span><span class="p">(</span><span class="mi">1</span><span class="p">,</span> <span class="mi">4</span><span class="p">,</span> <span class="mi">1</span><span class="p">,</span> <span class="mi">2048</span><span class="p">,</span> <span class="mi">2048</span><span class="p">,</span> <span class="mi">128</span><span class="p">,</span> <span class="kc">True</span><span class="p">,</span> <span class="n">dtype</span><span class="o">=</span><span class="n">dtype</span><span class="p">,</span> <span class="n">device</span><span class="o">=</span><span class="n">device</span><span class="p">)</span>
<span class="lineno">155</span> <span class="n">test_fwd_bwd</span><span class="p">(</span><span class="mi">16</span><span class="p">,</span> <span class="mi">32</span><span class="p">,</span> <span class="mi">8</span><span class="p">,</span> <span class="mi">2001</span><span class="p">,</span> <span class="mi">4001</span><span class="p">,</span> <span class="mi">128</span><span class="p">,</span> <span class="kc">False</span><span class="p">,</span> <span class="n">dtype</span><span class="o">=</span><span class="n">dtype</span><span class="p">,</span> <span class="n">device</span><span class="o">=</span><span class="n">device</span><span class="p">)</span>
<span class="lineno">156</span> <span class="n">test_fwd_bwd</span><span class="p">(</span><span class="mi">4</span><span class="p">,</span> <span class="mi">32</span><span class="p">,</span> <span class="mi">8</span><span class="p">,</span> <span class="mi">2048</span><span class="p">,</span> <span class="mi">1024</span><span class="p">,</span> <span class="mi">128</span><span class="p">,</span> <span class="kc">False</span><span class="p">,</span> <span class="n">dtype</span><span class="o">=</span><span class="n">dtype</span><span class="p">,</span> <span class="n">device</span><span class="o">=</span><span class="n">device</span><span class="p">)</span>
<span class="lineno">157</span> <span class="n">test_fwd_bwd</span><span class="p">(</span><span class="mi">4</span><span class="p">,</span> <span class="mi">32</span><span class="p">,</span> <span class="mi">8</span><span class="p">,</span> <span class="mi">2001</span><span class="p">,</span> <span class="mi">4001</span><span class="p">,</span> <span class="mi">128</span><span class="p">,</span> <span class="kc">True</span><span class="p">,</span> <span class="n">dtype</span><span class="o">=</span><span class="n">dtype</span><span class="p">,</span> <span class="n">device</span><span class="o">=</span><span class="n">device</span><span class="p">)</span>
<span class="lineno">158</span>
<span class="lineno">159</span> <span class="n">_conf</span> <span class="o">=</span> <span class="p">{</span>
<span class="lineno">160</span> <span class="s1">&#39;batch_size&#39;</span><span class="p">:</span> <span class="mi">16</span><span class="p">,</span>
<span class="lineno">161</span> <span class="s1">&#39;k_heads&#39;</span><span class="p">:</span> <span class="mi">8</span><span class="p">,</span>
<span class="lineno">162</span> <span class="s1">&#39;n_groups&#39;</span><span class="p">:</span> <span class="mi">4</span><span class="p">,</span>
<span class="lineno">163</span> <span class="s1">&#39;seq_len&#39;</span><span class="p">:</span> <span class="mi">2048</span><span class="p">,</span>
<span class="lineno">164</span> <span class="s1">&#39;d_head&#39;</span><span class="p">:</span> <span class="mi">128</span><span class="p">,</span>
<span class="lineno">165</span> <span class="p">}</span>
<span class="lineno">166</span>
<span class="lineno">167</span> <span class="k">for</span> <span class="n">_causal</span> <span class="ow">in</span> <span class="p">[</span><span class="kc">False</span><span class="p">,</span> <span class="kc">True</span><span class="p">]:</span>
<span class="lineno">168</span> <span class="k">for</span> <span class="n">is_bwd</span> <span class="ow">in</span> <span class="p">[</span><span class="kc">False</span><span class="p">,</span> <span class="kc">True</span><span class="p">]:</span>
<span class="lineno">169</span> <span class="n">logger</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="sa">f</span><span class="s1">&#39;</span><span class="si">{</span><span class="s2">&quot;Causal&quot;</span><span class="w"> </span><span class="k">if</span><span class="w"> </span><span class="n">_causal</span><span class="w"> </span><span class="k">else</span><span class="w"> </span><span class="s2">&quot;Non-causal&quot;</span><span class="si">}</span><span class="s1"> </span><span class="si">{</span><span class="s2">&quot; Backward&quot;</span><span class="w"> </span><span class="k">if</span><span class="w"> </span><span class="n">is_bwd</span><span class="w"> </span><span class="k">else</span><span class="w"> </span><span class="s2">&quot;&quot;</span><span class="si">}</span><span class="s1">&#39;</span><span class="p">,</span> <span class="n">logger</span><span class="o">.</span><span class="n">Text</span><span class="o">.</span><span class="n">title</span><span class="p">)</span>
<span class="lineno">170</span> <span class="n">measure_performance</span><span class="p">(</span><span class="sa">f</span><span class="s1">&#39;flash&#39;</span><span class="p">,</span> <span class="n">_perf_flash</span><span class="p">(</span><span class="n">causal</span><span class="o">=</span><span class="n">_causal</span><span class="p">,</span> <span class="n">device</span><span class="o">=</span><span class="n">device</span><span class="p">,</span> <span class="n">dtype</span><span class="o">=</span><span class="n">dtype</span><span class="p">,</span> <span class="o">**</span><span class="n">_conf</span><span class="p">),</span>
<span class="lineno">171</span> <span class="n">is_bwd</span><span class="o">=</span><span class="n">is_bwd</span><span class="p">,</span>
<span class="lineno">172</span> <span class="n">causal</span><span class="o">=</span><span class="n">_causal</span><span class="p">,</span> <span class="o">**</span><span class="n">_conf</span><span class="p">)</span>
<span class="lineno">173</span> <span class="n">measure_performance</span><span class="p">(</span><span class="sa">f</span><span class="s1">&#39;triton&#39;</span><span class="p">,</span> <span class="n">_perf_triton_fn</span><span class="p">(</span><span class="n">causal</span><span class="o">=</span><span class="n">_causal</span><span class="p">,</span> <span class="n">device</span><span class="o">=</span><span class="n">device</span><span class="p">,</span> <span class="n">dtype</span><span class="o">=</span><span class="n">dtype</span><span class="p">,</span> <span class="o">**</span><span class="n">_conf</span><span class="p">),</span>
<span class="lineno">174</span> <span class="n">is_bwd</span><span class="o">=</span><span class="n">is_bwd</span><span class="p">,</span>
<span class="lineno">175</span> <span class="n">causal</span><span class="o">=</span><span class="n">_causal</span><span class="p">,</span> <span class="o">**</span><span class="n">_conf</span><span class="p">)</span>
<span class="lineno">176</span>
<span class="lineno">177</span>
<span class="lineno">178</span><span class="k">if</span> <span class="vm">__name__</span> <span class="o">==</span> <span class="s2">&quot;__main__&quot;</span><span class="p">:</span>
<span class="lineno">179</span> <span class="n">main</span><span class="p">()</span></pre></div>
</div>
</div>
<div class='footer'>
<a href="https://labml.ai">labml.ai</a>
</div>
</div>
<script src=../../interactive.js?v=1"></script>
<script>
function handleImages() {
var images = document.querySelectorAll('p>img')
for (var i = 0; i < images.length; ++i) {
handleImage(images[i])
}
}
function handleImage(img) {
img.parentElement.style.textAlign = 'center'
var modal = document.createElement('div')
modal.id = 'modal'
var modalContent = document.createElement('div')
modal.appendChild(modalContent)
var modalImage = document.createElement('img')
modalContent.appendChild(modalImage)
var span = document.createElement('span')
span.classList.add('close')
span.textContent = 'x'
modal.appendChild(span)
img.onclick = function () {
console.log('clicked')
document.body.appendChild(modal)
modalImage.src = img.src
}
span.onclick = function () {
document.body.removeChild(modal)
}
}
handleImages()
</script>
</body>
</html>