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runtime: malloc sampling, pprof interface

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R=r
CC=golang-dev
https://golang.org/cl/719041
This commit is contained in:
Russ Cox 2010-03-24 09:40:09 -07:00
parent 6b6c3993d5
commit 6eb251f244
14 changed files with 397 additions and 42 deletions
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26
src/pkg/runtime/malloc.cgo
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@ -15,6 +15,8 @@ package runtime
MHeap mheap;
MStats mstats;
extern volatile int32 ·MemProfileRate;
// Same algorithm from chan.c, but a different
// instance of the static uint32 x.
// Not protected by a lock - let the threads use
@ -36,7 +38,7 @@ fastrand1(void)
void*
mallocgc(uintptr size, uint32 refflag, int32 dogc, int32 zeroed, int32 skip_depth)
{
int32 sizeclass;
int32 sizeclass, rate;
MCache *c;
uintptr npages;
MSpan *s;
@ -91,19 +93,19 @@ mallocgc(uintptr size, uint32 refflag, int32 dogc, int32 zeroed, int32 skip_dept
m->mallocing = 0;
if(!(refflag & RefNoProfiling) && malloc_profile != MProf_None) {
switch(malloc_profile) {
case MProf_Sample:
if(m->mcache->next_sample > size) {
m->mcache->next_sample -= size;
break;
}
m->mcache->next_sample = fastrand1() & (256*1024 - 1); // sample every 128 kB allocated, on average
// fall through
case MProf_All:
if(!(refflag & RefNoProfiling) && (rate = ·MemProfileRate) > 0) {
if(size >= rate)
goto profile;
if(m->mcache->next_sample > size)
m->mcache->next_sample -= size;
else {
// pick next profile time
if(rate > 0x3fffffff) // make 2*rate not overflow
rate = 0x3fffffff;
m->mcache->next_sample = fastrand1() % (2*rate);
profile:
*ref |= RefProfiled;
MProf_Malloc(skip_depth+1, v, size);
break;
}
}