Continuing the war on stacks, we can reduce the amount of stack required
per-RPC by combining defers from different components into one.
Each defer statement in process{Unary,Streaming}RPC goes on the stack
and occupies about 56-64 bytes the entire lifetime of an RPC, which
could be very long. More importantly, a call to runtime.morestack is
often required to allocate a new, larger stack when the handler
goroutine runs out of stack memory (Go's default stack size is 2 KiB).
Before:
$ go tool objdump <binary> | grep "TEXT.*processUnaryRPC(SB)" -A 10 | grep "SUBQ.*SP"
server.go:867 0x9132fb 4881ec80030000 SUBQ $0x380, SP
$ go tool objdump <binary> | grep "TEXT.*processStreamingRPC(SB)" -A 10 | grep "SUBQ.*SP"
server.go:1099 0x9151bb 4881ec68020000 SUBQ $0x268, SP
After:
$ go tool objdump <binary> | grep "TEXT.*processUnaryRPC(SB)" -A 10 | grep "SUBQ.*SP"
server.go:867 0x9132fb 4881ecd0020000 SUBQ $0x2d0, SP
$ go tool objdump <binary> | grep "TEXT.*processStreamingRPC(SB)" -A 10 | grep "SUBQ.*SP"
server.go:1116 0x9150fb 4881ecf8010000 SUBQ $0x1f8, SP
As one can observe, the processUnaryRPC's stack goes down from 0x380
bytes to 0x2d0 bytes (896 - 720 = 176 bytes) while processStreamingRPC's
stack goes down from 0x2d8 bytes to 0x1f8 bytes (616 - 504 = 112 bytes).
There are probably other things we can do here, but these are some low
hanging fruits to pick off.
The client-side traces were otherwise only showing `RPC: to <nil>`,
which is not helpful.
Also clean up construction of traceInfo and firstLine in a few places.
Also includes:
- Export `NewLoggerFromConfigString` so it can be also used when config string is specified in another way (e.g. command line flag)
- Export `Logger` so user can install custom sink
- Add temp file sink implementation
This is a breaking change, but the transport package was never intended for use outside of grpc. Any current users that we are aware of are incorrect or have a preferred alternative.
Reverts grpc/grpc-go#2098
Appengine will fail with the error below:
```
go-app-builder: Failed parsing input: parser: bad import "syscall" in google.golang.org/grpc/channelz/funcs.go from GOPATH
```
The root cause of it is in type_linux.go.
629f6bc5e5/channelz/types_linux.go (L21-L25)
This reverts commit 7cc2837209c4fa87008717b4e94a085820d7d779.
The PR breaks darwin builds
src/google.golang.org/grpc/channelz/types_unix.go:35:15: undefined: unix.TCPInfo
* Don't send nil requests.
* Fix import name and get rid of condition.
* Let registered encoder deal with nil requests.
* Break encode into encode and compress.
