summaryrefslogtreecommitdiff
path: root/src/pkg/runtime/mprof.goc
blob: 5b92cec95c72856053f84bf785cf8875db084dae (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
// Copyright 2009 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.

// Malloc profiling.
// Patterned after tcmalloc's algorithms; shorter code.

package runtime
#include "runtime.h"
#include "arch_GOARCH.h"
#include "malloc.h"
#include "defs_GOOS_GOARCH.h"
#include "type.h"

// NOTE(rsc): Everything here could use cas if contention became an issue.
static Lock proflock;

// All memory allocations are local and do not escape outside of the profiler.
// The profiler is forbidden from referring to garbage-collected memory.

enum { MProf, BProf };  // profile types

// Per-call-stack profiling information.
// Lookup by hashing call stack into a linked-list hash table.
typedef struct Bucket Bucket;
struct Bucket
{
	Bucket	*next;	// next in hash list
	Bucket	*allnext;	// next in list of all mbuckets/bbuckets
	int32	typ;
	// Generally unions can break precise GC,
	// this one is fine because it does not contain pointers.
	union
	{
		struct  // typ == MProf
		{
			uintptr	allocs;
			uintptr	frees;
			uintptr	alloc_bytes;
			uintptr	free_bytes;
			uintptr	recent_allocs;  // since last gc
			uintptr	recent_frees;
			uintptr	recent_alloc_bytes;
			uintptr	recent_free_bytes;
		};
		struct  // typ == BProf
		{
			int64	count;
			int64	cycles;
		};
	};
	uintptr	hash;
	uintptr	nstk;
	uintptr	stk[1];
};
enum {
	BuckHashSize = 179999,
};
static Bucket **buckhash;
static Bucket *mbuckets;  // memory profile buckets
static Bucket *bbuckets;  // blocking profile buckets
static uintptr bucketmem;

// Return the bucket for stk[0:nstk], allocating new bucket if needed.
static Bucket*
stkbucket(int32 typ, uintptr *stk, int32 nstk, bool alloc)
{
	int32 i;
	uintptr h;
	Bucket *b;

	if(buckhash == nil) {
		buckhash = runtime·SysAlloc(BuckHashSize*sizeof buckhash[0], &mstats.buckhash_sys);
		if(buckhash == nil)
			runtime·throw("runtime: cannot allocate memory");
	}

	// Hash stack.
	h = 0;
	for(i=0; i<nstk; i++) {
		h += stk[i];
		h += h<<10;
		h ^= h>>6;
	}
	h += h<<3;
	h ^= h>>11;

	i = h%BuckHashSize;
	for(b = buckhash[i]; b; b=b->next)
		if(b->typ == typ && b->hash == h && b->nstk == nstk &&
		   runtime·mcmp((byte*)b->stk, (byte*)stk, nstk*sizeof stk[0]) == 0)
			return b;

	if(!alloc)
		return nil;

	b = runtime·persistentalloc(sizeof *b + nstk*sizeof stk[0], 0, &mstats.buckhash_sys);
	bucketmem += sizeof *b + nstk*sizeof stk[0];
	runtime·memmove(b->stk, stk, nstk*sizeof stk[0]);
	b->typ = typ;
	b->hash = h;
	b->nstk = nstk;
	b->next = buckhash[i];
	buckhash[i] = b;
	if(typ == MProf) {
		b->allnext = mbuckets;
		mbuckets = b;
	} else {
		b->allnext = bbuckets;
		bbuckets = b;
	}
	return b;
}

static void
MProf_GC(void)
{
	Bucket *b;

	for(b=mbuckets; b; b=b->allnext) {
		b->allocs += b->recent_allocs;
		b->frees += b->recent_frees;
		b->alloc_bytes += b->recent_alloc_bytes;
		b->free_bytes += b->recent_free_bytes;
		b->recent_allocs = 0;
		b->recent_frees = 0;
		b->recent_alloc_bytes = 0;
		b->recent_free_bytes = 0;
	}
}

// Record that a gc just happened: all the 'recent' statistics are now real.
void
runtime·MProf_GC(void)
{
	runtime·lock(&proflock);
	MProf_GC();
	runtime·unlock(&proflock);
}

// Map from pointer to Bucket* that allocated it.
// Three levels:
//	Linked-list hash table for top N-AddrHashShift bits.
//	Array index for next AddrDenseBits bits.
//	Linked list for next AddrHashShift-AddrDenseBits bits.
// This is more efficient than using a general map,
// because of the typical clustering of the pointer keys.

typedef struct AddrHash AddrHash;
typedef struct AddrEntry AddrEntry;

enum {
	AddrHashBits = 12,	// good for 4GB of used address space
	AddrHashShift = 20,	// each AddrHash knows about 1MB of address space
	AddrDenseBits = 8,	// good for a profiling rate of 4096 bytes
};

struct AddrHash
{
	AddrHash *next;	// next in top-level hash table linked list
	uintptr addr;	// addr>>20
	AddrEntry *dense[1<<AddrDenseBits];
};

struct AddrEntry
{
	AddrEntry *next;	// next in bottom-level linked list
	uint32 addr;
	Bucket *b;
};

static AddrHash **addrhash;	// points to (AddrHash*)[1<<AddrHashBits]
static AddrEntry *addrfree;
static uintptr addrmem;

// Multiplicative hash function:
// hashMultiplier is the bottom 32 bits of int((sqrt(5)-1)/2 * (1<<32)).
// This is a good multiplier as suggested in CLR, Knuth.  The hash
// value is taken to be the top AddrHashBits bits of the bottom 32 bits
// of the multiplied value.
enum {
	HashMultiplier = 2654435769U
};

// Set the bucket associated with addr to b.
static void
setaddrbucket(uintptr addr, Bucket *b)
{
	int32 i;
	uint32 h;
	AddrHash *ah;
	AddrEntry *e;

	h = (uint32)((addr>>AddrHashShift)*HashMultiplier) >> (32-AddrHashBits);
	for(ah=addrhash[h]; ah; ah=ah->next)
		if(ah->addr == (addr>>AddrHashShift))
			goto found;

	ah = runtime·persistentalloc(sizeof *ah, 0, &mstats.buckhash_sys);
	addrmem += sizeof *ah;
	ah->next = addrhash[h];
	ah->addr = addr>>AddrHashShift;
	addrhash[h] = ah;

found:
	if((e = addrfree) == nil) {
		e = runtime·persistentalloc(64*sizeof *e, 0, &mstats.buckhash_sys);
		addrmem += 64*sizeof *e;
		for(i=0; i+1<64; i++)
			e[i].next = &e[i+1];
		e[63].next = nil;
	}
	addrfree = e->next;
	e->addr = (uint32)~(addr & ((1<<AddrHashShift)-1));
	e->b = b;
	h = (addr>>(AddrHashShift-AddrDenseBits))&(nelem(ah->dense)-1);	// entry in dense is top 8 bits of low 20.
	e->next = ah->dense[h];
	ah->dense[h] = e;
}

// Get the bucket associated with addr and clear the association.
static Bucket*
getaddrbucket(uintptr addr)
{
	uint32 h;
	AddrHash *ah;
	AddrEntry *e, **l;
	Bucket *b;

	h = (uint32)((addr>>AddrHashShift)*HashMultiplier) >> (32-AddrHashBits);
	for(ah=addrhash[h]; ah; ah=ah->next)
		if(ah->addr == (addr>>AddrHashShift))
			goto found;
	return nil;

found:
	h = (addr>>(AddrHashShift-AddrDenseBits))&(nelem(ah->dense)-1);	// entry in dense is top 8 bits of low 20.
	for(l=&ah->dense[h]; (e=*l) != nil; l=&e->next) {
		if(e->addr == (uint32)~(addr & ((1<<AddrHashShift)-1))) {
			*l = e->next;
			b = e->b;
			e->next = addrfree;
			addrfree = e;
			return b;
		}
	}
	return nil;
}

// Called by malloc to record a profiled block.
void
runtime·MProf_Malloc(void *p, uintptr size)
{
	int32 nstk;
	uintptr stk[32];
	Bucket *b;

	nstk = runtime·callers(1, stk, 32);
	runtime·lock(&proflock);
	b = stkbucket(MProf, stk, nstk, true);
	b->recent_allocs++;
	b->recent_alloc_bytes += size;
	setaddrbucket((uintptr)p, b);
	runtime·unlock(&proflock);
}

// Called when freeing a profiled block.
void
runtime·MProf_Free(void *p, uintptr size)
{
	Bucket *b;

	runtime·lock(&proflock);
	b = getaddrbucket((uintptr)p);
	if(b != nil) {
		b->recent_frees++;
		b->recent_free_bytes += size;
	}
	runtime·unlock(&proflock);
}

int64 runtime·blockprofilerate;  // in CPU ticks

void
runtime·SetBlockProfileRate(intgo rate)
{
	int64 r;

	if(rate <= 0)
		r = 0;  // disable profiling
	else {
		// convert ns to cycles, use float64 to prevent overflow during multiplication
		r = (float64)rate*runtime·tickspersecond()/(1000*1000*1000);
		if(r == 0)
			r = 1;
	}
	runtime·atomicstore64((uint64*)&runtime·blockprofilerate, r);
}

void
runtime·blockevent(int64 cycles, int32 skip)
{
	int32 nstk;
	int64 rate;
	uintptr stk[32];
	Bucket *b;

	if(cycles <= 0)
		return;
	rate = runtime·atomicload64((uint64*)&runtime·blockprofilerate);
	if(rate <= 0 || (rate > cycles && runtime·fastrand1()%rate > cycles))
		return;

	nstk = runtime·callers(skip, stk, 32);
	runtime·lock(&proflock);
	b = stkbucket(BProf, stk, nstk, true);
	b->count++;
	b->cycles += cycles;
	runtime·unlock(&proflock);
}

// Go interface to profile data.  (Declared in debug.go)

// Must match MemProfileRecord in debug.go.
typedef struct Record Record;
struct Record {
	int64 alloc_bytes, free_bytes;
	int64 alloc_objects, free_objects;
	uintptr stk[32];
};

// Write b's data to r.
static void
record(Record *r, Bucket *b)
{
	int32 i;

	r->alloc_bytes = b->alloc_bytes;
	r->free_bytes = b->free_bytes;
	r->alloc_objects = b->allocs;
	r->free_objects = b->frees;
	for(i=0; i<b->nstk && i<nelem(r->stk); i++)
		r->stk[i] = b->stk[i];
	for(; i<nelem(r->stk); i++)
		r->stk[i] = 0;
}

func MemProfile(p Slice, include_inuse_zero bool) (n int, ok bool) {
	Bucket *b;
	Record *r;
	bool clear;

	runtime·lock(&proflock);
	n = 0;
	clear = true;
	for(b=mbuckets; b; b=b->allnext) {
		if(include_inuse_zero || b->alloc_bytes != b->free_bytes)
			n++;
		if(b->allocs != 0 || b->frees != 0)
			clear = false;
	}
	if(clear) {
		// Absolutely no data, suggesting that a garbage collection
		// has not yet happened. In order to allow profiling when
		// garbage collection is disabled from the beginning of execution,
		// accumulate stats as if a GC just happened, and recount buckets.
		MProf_GC();
		n = 0;
		for(b=mbuckets; b; b=b->allnext)
			if(include_inuse_zero || b->alloc_bytes != b->free_bytes)
				n++;
	}
	ok = false;
	if(n <= p.len) {
		ok = true;
		r = (Record*)p.array;
		for(b=mbuckets; b; b=b->allnext)
			if(include_inuse_zero || b->alloc_bytes != b->free_bytes)
				record(r++, b);
	}
	runtime·unlock(&proflock);
}

// Must match BlockProfileRecord in debug.go.
typedef struct BRecord BRecord;
struct BRecord {
	int64 count;
	int64 cycles;
	uintptr stk[32];
};

func BlockProfile(p Slice) (n int, ok bool) {
	Bucket *b;
	BRecord *r;
	int32 i;

	runtime·lock(&proflock);
	n = 0;
	for(b=bbuckets; b; b=b->allnext)
		n++;
	ok = false;
	if(n <= p.len) {
		ok = true;
		r = (BRecord*)p.array;
		for(b=bbuckets; b; b=b->allnext, r++) {
			r->count = b->count;
			r->cycles = b->cycles;
			for(i=0; i<b->nstk && i<nelem(r->stk); i++)
				r->stk[i] = b->stk[i];
			for(; i<nelem(r->stk); i++)
				r->stk[i] = 0;			
		}
	}
	runtime·unlock(&proflock);
}

// Must match StackRecord in debug.go.
typedef struct TRecord TRecord;
struct TRecord {
	uintptr stk[32];
};

func ThreadCreateProfile(p Slice) (n int, ok bool) {
	TRecord *r;
	M *first, *mp;
	
	first = runtime·atomicloadp(&runtime·allm);
	n = 0;
	for(mp=first; mp; mp=mp->alllink)
		n++;
	ok = false;
	if(n <= p.len) {
		ok = true;
		r = (TRecord*)p.array;
		for(mp=first; mp; mp=mp->alllink) {
			runtime·memmove(r->stk, mp->createstack, sizeof r->stk);
			r++;
		}
	}
}

func Stack(b Slice, all bool) (n int) {
	uintptr pc, sp;
	
	sp = runtime·getcallersp(&b);
	pc = (uintptr)runtime·getcallerpc(&b);

	if(all) {
		runtime·semacquire(&runtime·worldsema, false);
		m->gcing = 1;
		runtime·stoptheworld();
	}

	if(b.len == 0)
		n = 0;
	else{
		g->writebuf = (byte*)b.array;
		g->writenbuf = b.len;
		runtime·goroutineheader(g);
		runtime·traceback(pc, sp, 0, g);
		if(all)
			runtime·tracebackothers(g);
		n = b.len - g->writenbuf;
		g->writebuf = nil;
		g->writenbuf = 0;
	}
	
	if(all) {
		m->gcing = 0;
		runtime·semrelease(&runtime·worldsema);
		runtime·starttheworld();
	}
}

static void
saveg(uintptr pc, uintptr sp, G *gp, TRecord *r)
{
	int32 n;
	
	n = runtime·gentraceback((uintptr)pc, (uintptr)sp, 0, gp, 0, r->stk, nelem(r->stk), nil, nil, false);
	if(n < nelem(r->stk))
		r->stk[n] = 0;
}

func GoroutineProfile(b Slice) (n int, ok bool) {
	uintptr pc, sp;
	TRecord *r;
	G *gp;
	
	sp = runtime·getcallersp(&b);
	pc = (uintptr)runtime·getcallerpc(&b);
	
	ok = false;
	n = runtime·gcount();
	if(n <= b.len) {
		runtime·semacquire(&runtime·worldsema, false);
		m->gcing = 1;
		runtime·stoptheworld();

		n = runtime·gcount();
		if(n <= b.len) {
			ok = true;
			r = (TRecord*)b.array;
			saveg(pc, sp, g, r++);
			for(gp = runtime·allg; gp != nil; gp = gp->alllink) {
				if(gp == g || gp->status == Gdead)
					continue;
				saveg(gp->sched.pc, gp->sched.sp, gp, r++);
			}
		}
	
		m->gcing = 0;
		runtime·semrelease(&runtime·worldsema);
		runtime·starttheworld();
	}
}

void
runtime·mprofinit(void)
{
	addrhash = runtime·persistentalloc((1<<AddrHashBits)*sizeof *addrhash, 0, &mstats.buckhash_sys);
}