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go/src/pkg/runtime/runtime1.goc
Russ Cox 89f185fe8a all: remove 'extern register M *m' from runtime
The runtime has historically held two dedicated values g (current goroutine)
and m (current thread) in 'extern register' slots (TLS on x86, real registers
backed by TLS on ARM).

This CL removes the extern register m; code now uses g->m.

On ARM, this frees up the register that formerly held m (R9).
This is important for NaCl, because NaCl ARM code cannot use R9 at all.

The Go 1 macrobenchmarks (those with per-op times >= 10 µs) are unaffected:

BenchmarkBinaryTree17              5491374955     5471024381     -0.37%
BenchmarkFannkuch11                4357101311     4275174828     -1.88%
BenchmarkGobDecode                 11029957       11364184       +3.03%
BenchmarkGobEncode                 6852205        6784822        -0.98%
BenchmarkGzip                      650795967      650152275      -0.10%
BenchmarkGunzip                    140962363      141041670      +0.06%
BenchmarkHTTPClientServer          71581          73081          +2.10%
BenchmarkJSONEncode                31928079       31913356       -0.05%
BenchmarkJSONDecode                117470065      113689916      -3.22%
BenchmarkMandelbrot200             6008923        5998712        -0.17%
BenchmarkGoParse                   6310917        6327487        +0.26%
BenchmarkRegexpMatchMedium_1K      114568         114763         +0.17%
BenchmarkRegexpMatchHard_1K        168977         169244         +0.16%
BenchmarkRevcomp                   935294971      914060918      -2.27%
BenchmarkTemplate                  145917123      148186096      +1.55%

Minux previous reported larger variations, but these were caused by
run-to-run noise, not repeatable slowdowns.

Actual code changes by Minux.
I only did the docs and the benchmarking.

LGTM=dvyukov, iant, minux
R=minux, josharian, iant, dave, bradfitz, dvyukov
CC=golang-codereviews
https://golang.org/cl/109050043
2014-06-26 11:54:39 -04:00

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// Copyright 2010 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package runtime
#include "runtime.h"
#include "arch_GOARCH.h"
#include "type.h"
func GOMAXPROCS(n int) (ret int) {
ret = runtime·gomaxprocsfunc(n);
}
func NumCPU() (ret int) {
ret = runtime·ncpu;
}
func NumCgoCall() (ret int64) {
M *mp;
ret = 0;
for(mp=runtime·atomicloadp(&runtime·allm); mp; mp=mp->alllink)
ret += mp->ncgocall;
}
func newParFor(nthrmax uint32) (desc *ParFor) {
desc = runtime·parforalloc(nthrmax);
}
func parForSetup(desc *ParFor, nthr uint32, n uint32, ctx *byte, wait bool, body *byte) {
runtime·parforsetup(desc, nthr, n, ctx, wait, *(void(**)(ParFor*, uint32))body);
}
func parForDo(desc *ParFor) {
runtime·parfordo(desc);
}
func parForIters(desc *ParFor, tid uintptr) (start uintptr, end uintptr) {
runtime·parforiters(desc, tid, &start, &end);
}
func gogoBytes() (x int32) {
x = RuntimeGogoBytes;
}
func typestring(e Eface) (s String) {
s = *e.type->string;
}
func golockedOSThread() (ret bool) {
ret = runtime·lockedOSThread();
}
func NumGoroutine() (ret int) {
ret = runtime·gcount();
}
func getgoroot() (out String) {
byte *p;
p = runtime·getenv("GOROOT");
out = runtime·gostringnocopy(p);
}
/*
* We assume that all architectures turn faults and the like
* into apparent calls to runtime.sigpanic. If we see a "call"
* to runtime.sigpanic, we do not back up the PC to find the
* line number of the CALL instruction, because there is no CALL.
*/
void runtime·sigpanic(void);
func Caller(skip int) (retpc uintptr, retfile String, retline int, retbool bool) {
Func *f, *g;
uintptr pc;
uintptr rpc[2];
/*
* Ask for two PCs: the one we were asked for
* and what it called, so that we can see if it
* "called" sigpanic.
*/
retpc = 0;
if(runtime·callers(1+skip-1, rpc, 2) < 2) {
retfile = runtime·emptystring;
retline = 0;
retbool = false;
} else if((f = runtime·findfunc(rpc[1])) == nil) {
retfile = runtime·emptystring;
retline = 0;
retbool = true; // have retpc at least
} else {
retpc = rpc[1];
pc = retpc;
g = runtime·findfunc(rpc[0]);
if(pc > f->entry && (g == nil || g->entry != (uintptr)runtime·sigpanic))
pc--;
retline = runtime·funcline(f, pc, &retfile);
retbool = true;
}
}
func Callers(skip int, pc Slice) (retn int) {
// runtime.callers uses pc.array==nil as a signal
// to print a stack trace. Pick off 0-length pc here
// so that we don't let a nil pc slice get to it.
if(pc.len == 0)
retn = 0;
else
retn = runtime·callers(skip, (uintptr*)pc.array, pc.len);
}
func runtimepprof·runtime_cyclesPerSecond() (res int64) {
res = runtime·tickspersecond();
}
func sync·runtime_procPin() (p int) {
M *mp;
mp = g->m;
// Disable preemption.
mp->locks++;
p = mp->p->id;
}
func sync·runtime_procUnpin() {
g->m->locks--;
}