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cmd, runtime: remove PC_F & PC_B globals on Wasm
Following the previous CL, this removes more global variables on Wasm. PC_B is used mostly for intra-function jumps, and for a function telling its callee where to start or resume. This usage can be served by a parameter. The top level loop (wasm_pc_f_loop) uses PC_B for resuming a function. This value is either set by gogo, or loaded from the Go stack at function return. Instead of loading PC_B at each function return, we could make gogo stores PC_B at the same stack location, and let the top level loop do the load. This way, we don't need to use global PC_B to communicate with the top level loop, and we can replace global PC_B with a parameter. PC_F is similar. It is even more so in that the only reader is the top level loop. Let the top level loop read it from the stack, and we can get rid of PC_F entirely. PC_F and PC_B are used less entensively as SP, so this CL has smaller performance gain. Running on Chrome 74.0.3729.108 on Linux/AMD64, name old time/op new time/op delta BinaryTree17 16.6s ± 0% 16.2s ± 1% -2.59% (p=0.016 n=4+5) Fannkuch11 11.1s ± 1% 10.8s ± 0% -2.65% (p=0.008 n=5+5) FmtFprintfEmpty 231ns ± 1% 217ns ± 0% -6.06% (p=0.008 n=5+5) FmtFprintfString 407ns ± 3% 375ns ± 2% -7.81% (p=0.008 n=5+5) FmtFprintfInt 466ns ± 2% 430ns ± 0% -7.79% (p=0.016 n=5+4) FmtFprintfIntInt 719ns ± 2% 673ns ± 2% -6.37% (p=0.008 n=5+5) FmtFprintfPrefixedInt 706ns ± 1% 676ns ± 3% -4.31% (p=0.008 n=5+5) FmtFprintfFloat 1.01µs ± 1% 0.97µs ± 1% -4.30% (p=0.008 n=5+5) FmtManyArgs 2.67µs ± 1% 2.51µs ± 1% -5.95% (p=0.008 n=5+5) GobDecode 30.7ms ± 9% 31.3ms ±34% ~ (p=0.222 n=5+5) GobEncode 24.2ms ±23% 20.2ms ± 0% -16.36% (p=0.016 n=5+4) Gzip 852ms ± 0% 823ms ± 0% -3.38% (p=0.016 n=4+5) Gunzip 160ms ± 1% 151ms ± 1% -5.37% (p=0.008 n=5+5) JSONEncode 35.7ms ± 1% 34.3ms ± 1% -3.81% (p=0.008 n=5+5) JSONDecode 247ms ± 8% 254ms ± 7% ~ (p=0.548 n=5+5) Mandelbrot200 5.39ms ± 0% 5.41ms ± 0% +0.42% (p=0.008 n=5+5) GoParse 18.5ms ± 1% 18.3ms ± 2% ~ (p=0.343 n=4+4) RegexpMatchEasy0_32 424ns ± 2% 397ns ± 0% -6.23% (p=0.008 n=5+5) RegexpMatchEasy0_1K 2.88µs ± 0% 2.86µs ± 1% ~ (p=0.079 n=5+5) RegexpMatchEasy1_32 395ns ± 2% 370ns ± 1% -6.23% (p=0.008 n=5+5) RegexpMatchEasy1_1K 3.26µs ± 0% 3.19µs ± 1% -2.06% (p=0.008 n=5+5) RegexpMatchMedium_32 564ns ± 1% 532ns ± 0% -5.71% (p=0.008 n=5+5) RegexpMatchMedium_1K 146µs ± 2% 140µs ± 1% -4.62% (p=0.008 n=5+5) RegexpMatchHard_32 8.47µs ± 1% 7.91µs ± 1% -6.65% (p=0.008 n=5+5) RegexpMatchHard_1K 253µs ± 1% 236µs ± 2% -6.66% (p=0.008 n=5+5) Revcomp 1.78s ± 4% 1.76s ± 5% ~ (p=1.000 n=5+5) Template 292ms ±29% 269ms ± 5% ~ (p=0.690 n=5+5) TimeParse 1.61µs ± 4% 1.54µs ± 1% -4.42% (p=0.008 n=5+5) TimeFormat 1.66µs ± 3% 1.58µs ± 1% -5.22% (p=0.008 n=5+5) [Geo mean] 232µs 221µs -4.54% name old speed new speed delta GobDecode 25.0MB/s ± 8% 25.1MB/s ±27% ~ (p=0.222 n=5+5) GobEncode 32.8MB/s ±21% 38.0MB/s ± 0% +15.84% (p=0.016 n=5+4) Gzip 22.8MB/s ± 0% 23.6MB/s ± 0% +3.49% (p=0.016 n=4+5) Gunzip 121MB/s ± 1% 128MB/s ± 1% +5.68% (p=0.008 n=5+5) JSONEncode 54.4MB/s ± 1% 56.5MB/s ± 1% +3.97% (p=0.008 n=5+5) JSONDecode 7.88MB/s ± 8% 7.65MB/s ± 8% ~ (p=0.548 n=5+5) GoParse 3.07MB/s ± 8% 3.00MB/s ±22% ~ (p=0.579 n=5+5) RegexpMatchEasy0_32 75.6MB/s ± 2% 80.5MB/s ± 0% +6.58% (p=0.008 n=5+5) RegexpMatchEasy0_1K 356MB/s ± 0% 358MB/s ± 1% ~ (p=0.095 n=5+5) RegexpMatchEasy1_32 81.1MB/s ± 2% 86.5MB/s ± 1% +6.69% (p=0.008 n=5+5) RegexpMatchEasy1_1K 314MB/s ± 0% 320MB/s ± 0% +2.10% (p=0.008 n=5+5) RegexpMatchMedium_32 1.77MB/s ± 1% 1.88MB/s ± 0% +6.09% (p=0.016 n=5+4) RegexpMatchMedium_1K 6.99MB/s ± 2% 7.33MB/s ± 1% +4.83% (p=0.008 n=5+5) RegexpMatchHard_32 3.78MB/s ± 1% 4.04MB/s ± 1% +7.04% (p=0.008 n=5+5) RegexpMatchHard_1K 4.04MB/s ± 1% 4.33MB/s ± 2% +7.17% (p=0.008 n=5+5) Revcomp 143MB/s ± 4% 145MB/s ± 5% ~ (p=1.000 n=5+5) Template 6.77MB/s ±24% 7.22MB/s ± 5% ~ (p=0.690 n=5+5) [Geo mean] 24.4MB/s 25.4MB/s +4.18% Change-Id: Ib80716e62992aec28b2c4a96af280c278f83aa49 Reviewed-on: https://go-review.googlesource.com/c/go/+/173980 Run-TryBot: Cherry Zhang <cherryyz@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Richard Musiol <neelance@gmail.com>
This commit is contained in:
Cherry Zhang
parent
7ed7669c0d
commit
496b8dbbfc
5 changed files with 145 additions and 87 deletions
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@ -16,8 +16,6 @@ import (
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)
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var Register = map[string]int16{
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"PC_F": REG_PC_F,
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"PC_B": REG_PC_B,
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"SP": REG_SP,
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"CTXT": REG_CTXT,
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"g": REG_g,
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@ -60,6 +58,8 @@ var Register = map[string]int16{
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"F13": REG_F13,
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"F14": REG_F14,
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"F15": REG_F15,
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"PC_B": REG_PC_B,
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}
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var registerNames []string
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@ -368,20 +368,31 @@ func preprocess(ctxt *obj.Link, s *obj.LSym, newprog obj.ProgAlloc) {
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break
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}
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// reset PC_B to function entry
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p = appendp(p, AI32Const, constAddr(0))
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p = appendp(p, ASet, regAddr(REG_PC_B))
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// low-level WebAssembly call to function
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switch jmp.To.Type {
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case obj.TYPE_MEM:
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if !notUsePC_B[jmp.To.Sym.Name] {
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// Set PC_B parameter to function entry.
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p = appendp(p, AI32Const, constAddr(0))
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}
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p = appendp(p, ACall, jmp.To)
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case obj.TYPE_NONE:
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// (target PC is on stack)
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p = appendp(p, AI32WrapI64)
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p = appendp(p, AI32Const, constAddr(16)) // only needs PC_F bits (16-31), PC_B bits (0-15) are zero
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p = appendp(p, AI32ShrU)
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// Set PC_B parameter to function entry.
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// We need to push this before pushing the target PC_F,
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// so temporarily pop PC_F, using our REG_PC_B as a
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// scratch register, and push it back after pushing 0.
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p = appendp(p, ASet, regAddr(REG_PC_B))
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p = appendp(p, AI32Const, constAddr(0))
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p = appendp(p, AGet, regAddr(REG_PC_B))
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p = appendp(p, ACallIndirect)
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default:
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panic("bad target for JMP")
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}
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@ -419,20 +430,31 @@ func preprocess(ctxt *obj.Link, s *obj.LSym, newprog obj.ProgAlloc) {
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})
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p = appendp(p, AI64Store, constAddr(0))
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// reset PC_B to function entry
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p = appendp(p, AI32Const, constAddr(0))
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p = appendp(p, ASet, regAddr(REG_PC_B))
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// low-level WebAssembly call to function
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switch call.To.Type {
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case obj.TYPE_MEM:
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if !notUsePC_B[call.To.Sym.Name] {
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// Set PC_B parameter to function entry.
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p = appendp(p, AI32Const, constAddr(0))
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}
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p = appendp(p, ACall, call.To)
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case obj.TYPE_NONE:
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// (target PC is on stack)
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p = appendp(p, AI32WrapI64)
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p = appendp(p, AI32Const, constAddr(16)) // only needs PC_F bits (16-31), PC_B bits (0-15) are zero
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p = appendp(p, AI32ShrU)
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// Set PC_B parameter to function entry.
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// We need to push this before pushing the target PC_F,
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// so temporarily pop PC_F, using our PC_B as a
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// scratch register, and push it back after pushing 0.
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p = appendp(p, ASet, regAddr(REG_PC_B))
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p = appendp(p, AI32Const, constAddr(0))
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p = appendp(p, AGet, regAddr(REG_PC_B))
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p = appendp(p, ACallIndirect)
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default:
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panic("bad target for CALL")
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}
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@ -465,7 +487,13 @@ func preprocess(ctxt *obj.Link, s *obj.LSym, newprog obj.ProgAlloc) {
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// jump to before the call if jmpdefer has reset the return address to the call's PC
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if call.To.Sym == deferreturn {
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p = appendp(p, AGet, regAddr(REG_PC_B))
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// get PC_B from -8(SP)
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p = appendp(p, AGet, regAddr(REG_SP))
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p = appendp(p, AI32Const, constAddr(8))
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p = appendp(p, AI32Sub)
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p = appendp(p, AI32Load16U, constAddr(0))
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p = appendp(p, ATee, regAddr(REG_PC_B))
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p = appendp(p, AI32Const, constAddr(call.Pc))
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p = appendp(p, AI32Eq)
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p = appendp(p, ABrIf, constAddr(0))
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@ -487,9 +515,8 @@ func preprocess(ctxt *obj.Link, s *obj.LSym, newprog obj.ProgAlloc) {
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}
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if ret.To.Type == obj.TYPE_MEM {
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// reset PC_B to function entry
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// Set PC_B parameter to function entry.
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p = appendp(p, AI32Const, constAddr(0))
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p = appendp(p, ASet, regAddr(REG_PC_B))
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// low-level WebAssembly call to function
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p = appendp(p, ACall, ret.To)
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@ -497,16 +524,6 @@ func preprocess(ctxt *obj.Link, s *obj.LSym, newprog obj.ProgAlloc) {
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break
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}
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// read return PC_F from Go stack
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p = appendp(p, AGet, regAddr(REG_SP))
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p = appendp(p, AI32Load16U, constAddr(2))
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p = appendp(p, ASet, regAddr(REG_PC_F))
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// read return PC_B from Go stack
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p = appendp(p, AGet, regAddr(REG_SP))
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p = appendp(p, AI32Load16U, constAddr(0))
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p = appendp(p, ASet, regAddr(REG_PC_B))
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// SP += 8
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p = appendp(p, AGet, regAddr(REG_SP))
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p = appendp(p, AI32Const, constAddr(8))
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@ -771,16 +788,38 @@ func countRegisters(s *obj.LSym) (numI, numF int16) {
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return
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}
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// Most of the Go functions has a single parameter (PC_B) in
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// Wasm ABI. This is a list of exceptions.
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var notUsePC_B = map[string]bool{
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"_rt0_wasm_js": true,
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"wasm_export_run": true,
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"wasm_export_resume": true,
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"wasm_export_getsp": true,
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"wasm_pc_f_loop": true,
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"runtime.wasmMove": true,
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"runtime.wasmZero": true,
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"runtime.wasmDiv": true,
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"runtime.wasmTruncS": true,
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"runtime.wasmTruncU": true,
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"runtime.gcWriteBarrier": true,
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"cmpbody": true,
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"memeqbody": true,
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"memcmp": true,
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"memchr": true,
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}
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func assemble(ctxt *obj.Link, s *obj.LSym, newprog obj.ProgAlloc) {
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w := new(bytes.Buffer)
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hasLocalSP := false
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hasPC_B := false
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var r0, f0 int16
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// Function starts with declaration of locals: numbers and types.
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// Some functions use a special calling convention.
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switch s.Name {
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case "wasm_export_run", "runtime.wasmMove", "runtime.wasmZero", "runtime.wasmDiv", "runtime.wasmTruncS", "runtime.wasmTruncU", "memeqbody":
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case "_rt0_wasm_js", "wasm_export_run", "wasm_export_resume", "wasm_export_getsp", "wasm_pc_f_loop",
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"runtime.wasmMove", "runtime.wasmZero", "runtime.wasmDiv", "runtime.wasmTruncS", "runtime.wasmTruncU", "memeqbody":
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writeUleb128(w, 0) // number of sets of locals
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case "memchr", "memcmp":
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writeUleb128(w, 1) // number of sets of locals
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@ -797,9 +836,10 @@ func assemble(ctxt *obj.Link, s *obj.LSym, newprog obj.ProgAlloc) {
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default:
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// Normal calling convention: No WebAssembly parameters. First local variable is local SP cache.
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hasLocalSP = true
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hasPC_B = true
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numI, numF := countRegisters(s)
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r0 = 1
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f0 = 1 + numI
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r0 = 2
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f0 = 2 + numI
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numTypes := 1
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if numI > 0 {
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@ -826,6 +866,7 @@ func assemble(ctxt *obj.Link, s *obj.LSym, newprog obj.ProgAlloc) {
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// Copy SP from its global variable into a local variable. Accessing a local variable is more efficient.
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updateLocalSP(w)
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}
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for p := s.Func.Text; p != nil; p = p.Link {
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switch p.As {
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case AGet:
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@ -836,10 +877,16 @@ func assemble(ctxt *obj.Link, s *obj.LSym, newprog obj.ProgAlloc) {
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switch {
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case reg == REG_SP && hasLocalSP:
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w.WriteByte(0x20) // local.get
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writeUleb128(w, 0) // local SP
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case reg >= REG_PC_F && reg <= REG_PAUSE:
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writeUleb128(w, 1) // local SP
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case reg >= REG_SP && reg <= REG_PAUSE:
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w.WriteByte(0x23) // global.get
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writeUleb128(w, uint64(reg-REG_PC_F))
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writeUleb128(w, uint64(reg-REG_SP))
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case reg == REG_PC_B:
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if !hasPC_B {
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panic(fmt.Sprintf("PC_B is not used in %s", s.Name))
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}
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w.WriteByte(0x20) // local.get (i32)
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writeUleb128(w, 0) // local PC_B
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case reg >= REG_R0 && reg <= REG_R15:
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w.WriteByte(0x20) // local.get (i64)
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writeUleb128(w, uint64(r0+(reg-REG_R0)))
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}
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reg := p.To.Reg
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switch {
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case reg >= REG_PC_F && reg <= REG_PAUSE:
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case reg >= REG_SP && reg <= REG_PAUSE:
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if reg == REG_SP && hasLocalSP {
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w.WriteByte(0x22) // local.tee
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writeUleb128(w, 0) // local SP
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writeUleb128(w, 1) // local SP
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}
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w.WriteByte(0x24) // global.set
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writeUleb128(w, uint64(reg-REG_PC_F))
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case reg >= REG_R0 && reg <= REG_F15:
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writeUleb128(w, uint64(reg-REG_SP))
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case reg >= REG_R0 && reg <= REG_PC_B:
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if p.Link.As == AGet && p.Link.From.Reg == reg {
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w.WriteByte(0x22) // local.tee
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p = p.Link
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} else {
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w.WriteByte(0x21) // local.set
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}
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if reg <= REG_R15 {
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if reg == REG_PC_B {
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if !hasPC_B {
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panic(fmt.Sprintf("PC_B is not used in %s", s.Name))
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}
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writeUleb128(w, 0) // local PC_B
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} else if reg <= REG_R15 {
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writeUleb128(w, uint64(r0+(reg-REG_R0)))
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} else {
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writeUleb128(w, uint64(f0+(reg-REG_F0)))
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}
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reg := p.To.Reg
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switch {
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case reg == REG_PC_B:
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if !hasPC_B {
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panic(fmt.Sprintf("PC_B is not used in %s", s.Name))
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}
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w.WriteByte(0x22) // local.tee (i32)
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writeUleb128(w, 0) // local PC_B
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case reg >= REG_R0 && reg <= REG_R15:
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w.WriteByte(0x22) // local.tee (i64)
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writeUleb128(w, uint64(r0+(reg-REG_R0)))
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}
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func updateLocalSP(w *bytes.Buffer) {
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w.WriteByte(0x23) // global.get
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writeUleb128(w, uint64(REG_SP-REG_PC_F)) // SP
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w.WriteByte(0x21) // local.set
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writeUleb128(w, 0) // local SP
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w.WriteByte(0x23) // global.get
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writeUleb128(w, 0) // global SP
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w.WriteByte(0x21) // local.set
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writeUleb128(w, 1) // local SP
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}
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func align(as obj.As) uint64 {
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