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runtime/pprof: emit end-of-log marker at end of CPU profile.

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R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/6489065
This commit is contained in:
Alan Donovan 2012-09-04 14:34:03 -04:00
parent d353d43d36
commit b2458ff75c
2 changed files with 25 additions and 5 deletions
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14
src/pkg/runtime/cpuprof.c
View File

@ -99,6 +99,7 @@ struct Profile {
uint32 wtoggle;
bool wholding; // holding & need to release a log half
bool flushing; // flushing hash table - profile is over
bool eod_sent; // special end-of-data record sent; => flushing
};
static Lock lk;
@ -109,6 +110,8 @@ static void add(Profile*, uintptr*, int32);
static bool evict(Profile*, Entry*);
static bool flushlog(Profile*);
static uintptr eod[3] = {0, 1, 0};
// LostProfileData is a no-op function used in profiles
// to mark the number of profiling stack traces that were
// discarded due to slow data writers.
@ -163,6 +166,7 @@ runtime·SetCPUProfileRate(int32 hz)
prof->wholding = false;
prof->wtoggle = 0;
prof->flushing = false;
prof->eod_sent = false;
runtime·noteclear(&prof->wait);
runtime·setcpuprofilerate(tick, hz);
@ -409,6 +413,16 @@ breakflush:
}
// Made it through the table without finding anything to log.
if(!p->eod_sent) {
// We may not have space to append this to the partial log buf,
// so we always return a new slice for the end-of-data marker.
p->eod_sent = true;
ret.array = (byte*)eod;
ret.len = sizeof eod;
ret.cap = ret.len;
return ret;
}
// Finally done. Clean up and return nil.
p->flushing = false;
if(!runtime·cas(&p->handoff, p->handoff, 0))

16
src/pkg/runtime/pprof/pprof_test.go
View File

@ -49,19 +49,25 @@ func TestCPUProfile(t *testing.T) {
// Convert []byte to []uintptr.
bytes := prof.Bytes()
l := len(bytes) / int(unsafe.Sizeof(uintptr(0)))
val := *(*[]uintptr)(unsafe.Pointer(&bytes))
val = val[:len(bytes)/int(unsafe.Sizeof(uintptr(0)))]
val = val[:l]
if len(val) < 10 {
if l < 13 {
t.Fatalf("profile too short: %#x", val)
}
if val[0] != 0 || val[1] != 3 || val[2] != 0 || val[3] != 1e6/100 || val[4] != 0 {
t.Fatalf("unexpected header %#x", val[:5])
hd, val, tl := val[:5], val[5:l-3], val[l-3:]
if hd[0] != 0 || hd[1] != 3 || hd[2] != 0 || hd[3] != 1e6/100 || hd[4] != 0 {
t.Fatalf("unexpected header %#x", hd)
}
if tl[0] != 0 || tl[1] != 1 || tl[2] != 0 {
t.Fatalf("malformed end-of-data marker %#x", tl)
}
// Check that profile is well formed and contains ChecksumIEEE.
found := false
val = val[5:]
for len(val) > 0 {
if len(val) < 2 || val[0] < 1 || val[1] < 1 || uintptr(len(val)) < 2+val[1] {
t.Fatalf("malformed profile. leftover: %#x", val)