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runtime: use manual stack for garbage collection

Browse Source 
Old code was using recursion to traverse object graph.
New code uses an explicit stack, cutting the per-pointer
footprint to two words during the recursion and avoiding
the standard allocator and stack splitting code.

in test/garbage:

Reduces parser runtime by 2-3%
Reduces Peano runtime by 40%
Increases tree runtime by 4-5%

R=r
CC=golang-dev
https://golang.org/cl/2150042
This commit is contained in:
Russ Cox 2010-09-07 09:57:22 -04:00
parent 6f5f558c10
commit d4cc557b0d
20 changed files with 217 additions and 78 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
src/pkg/runtime/darwin/386/sys.s
View File

@ -42,6 +42,13 @@ TEXT ·mmap(SB),7,$0
CALL notok(SB)
RET
TEXT ·munmap(SB),7,$0
MOVL $73, AX
INT $0x80
JAE 2(PC)
CALL notok(SB)
RET
// void gettime(int64 *sec, int32 *usec)
TEXT gettime(SB), 7, $32
LEAL 12(SP), AX // must be non-nil, unused

9
src/pkg/runtime/darwin/amd64/sys.s
View File

@ -107,6 +107,15 @@ TEXT ·mmap(SB),7,$0
CALL notok(SB)
RET
TEXT ·munmap(SB),7,$0
MOVQ 8(SP), DI // arg 1 addr
MOVQ 16(SP), SI // arg 2 len
MOVL $(0x2000000+73), AX // syscall entry
SYSCALL
JCC 2(PC)
CALL notok(SB)
RET
TEXT notok(SB),7,$0
MOVL $0xf1, BP
MOVQ BP, (BP)

4
src/pkg/runtime/darwin/mem.c
View File

@ -21,8 +21,6 @@ SysUnused(void *v, uintptr n)
void
SysFree(void *v, uintptr n)
{
USED(v);
USED(n);
// TODO(rsc): call munmap
runtime_munmap(v, n);
}

9
src/pkg/runtime/debug.go
View File

@ -36,10 +36,11 @@ type MemStatsType struct {
Mallocs uint64 // number of mallocs
// Main allocation heap statistics.
HeapAlloc uint64 // bytes allocated and still in use
HeapSys uint64 // bytes obtained from system
HeapIdle uint64 // bytes in idle spans
HeapInuse uint64 // bytes in non-idle span
HeapAlloc uint64 // bytes allocated and still in use
HeapSys uint64 // bytes obtained from system
HeapIdle uint64 // bytes in idle spans
HeapInuse uint64 // bytes in non-idle span
HeapObjects uint64 // total number of allocated objects
// Low-level fixed-size structure allocator statistics.
// Inuse is bytes used now.

7
src/pkg/runtime/freebsd/386/sys.s
View File

@ -84,6 +84,13 @@ TEXT ·mmap(SB),7,$32
CALL notok(SB)
RET
TEXT ·munmap(SB),7,$-4
MOVL $73, AX
INT $0x80
JAE 2(PC)
CALL notok(SB)
RET
TEXT gettime(SB), 7, $32
MOVL $116, AX
LEAL 12(SP), BX

9
src/pkg/runtime/freebsd/amd64/sys.s
View File

@ -116,6 +116,15 @@ TEXT ·mmap(SB),7,$0
CALL notok(SB)
RET
TEXT ·munmap(SB),7,$0
MOVQ 8(SP), DI // arg 1 addr
MOVQ 16(SP), SI // arg 2 len
MOVL $73, AX
SYSCALL
JCC 2(PC)
CALL notok(SB)
RET
TEXT notok(SB),7,$-8
MOVL $0xf1, BP
MOVQ BP, (BP)

4
src/pkg/runtime/freebsd/mem.c
View File

@ -21,8 +21,6 @@ SysUnused(void *v, uintptr n)
void
SysFree(void *v, uintptr n)
{
USED(v);
USED(n);
// TODO(rsc): call munmap
runtime_munmap(v, n);
}

10
src/pkg/runtime/linux/386/sys.s
View File

@ -110,6 +110,16 @@ TEXT ·mmap(SB),7,$0
INCL AX
RET
TEXT ·munmap(SB),7,$0
MOVL $91, AX // munmap
MOVL 4(SP), BX
MOVL 8(SP), CX
INT $0x80
CMPL AX, $0xfffff001
JLS 2(PC)
INT $3
RET
// int32 futex(int32 *uaddr, int32 op, int32 val,
// struct timespec *timeout, int32 *uaddr2, int32 val2);
TEXT futex(SB),7,$0

12
src/pkg/runtime/linux/amd64/sys.s
View File

@ -100,7 +100,7 @@ TEXT ·mmap(SB),7,$0
MOVL 32(SP), R8
MOVL 36(SP), R9
MOVL $9, AX // syscall entry
MOVL $9, AX // mmap
SYSCALL
CMPQ AX, $0xfffffffffffff001
JLS 3(PC)
@ -108,6 +108,16 @@ TEXT ·mmap(SB),7,$0
INCQ AX
RET
TEXT munmap(SB),7,$0
MOVQ 8(SP), DI
MOVQ 16(SP), SI
MOVQ $11, AX // munmap
SYSCALL
CMPQ AX, $0xfffffffffffff001
JLS 2(PC)
CALL notok(SB)
RET
TEXT notok(SB),7,$0
MOVQ $0xf1, BP
MOVQ BP, (BP)

8
src/pkg/runtime/linux/arm/sys.s
View File

@ -25,6 +25,7 @@
#define SYS_gettid (SYS_BASE + 224)
#define SYS_futex (SYS_BASE + 240)
#define SYS_exit_group (SYS_BASE + 248)
#define SYS_munmap (SYS_BASE + 91)
#define ARM_BASE (SYS_BASE + 0x0f0000)
#define SYS_ARM_cacheflush (ARM_BASE + 2)
@ -64,6 +65,13 @@ TEXT ·mmap(SB),7,$0
SWI $0
RET
TEXT ·mmap(SB),7,$0
MOVW 0(FP), R0
MOVW 4(FP), R1
MOVW $SYS_munmap, R7
SWI $0
RET
TEXT gettime(SB),7,$32
/* dummy version - return 0,0 */
MOVW $0, R1

4
src/pkg/runtime/linux/mem.c
View File

@ -33,8 +33,6 @@ SysUnused(void *v, uintptr n)
void
SysFree(void *v, uintptr n)
{
USED(v);
USED(n);
// TODO(rsc): call munmap
runtime_munmap(v, n);
}

2
src/pkg/runtime/malloc.h
View File

@ -183,6 +183,7 @@ struct MStats
uint64 heap_sys; // bytes obtained from system
uint64 heap_idle; // bytes in idle spans
uint64 heap_inuse; // bytes in non-idle spans
uint64 heap_objects; // total number of allocated objects
// Statistics about allocation of low-level fixed-size structures.
// Protected by FixAlloc locks.
@ -251,6 +252,7 @@ struct MCache
MCacheList list[NumSizeClasses];
uint64 size;
int64 local_alloc; // bytes allocated (or freed) since last lock of heap
int64 local_objects; // objects allocated (or freed) since last lock of heap
int32 next_sample; // trigger heap sample after allocating this many bytes
};

7
src/pkg/runtime/mcache.c
View File

@ -47,6 +47,7 @@ MCache_Alloc(MCache *c, int32 sizeclass, uintptr size, int32 zeroed)
}
}
c->local_alloc += size;
c->local_objects++;
return v;
}
@ -88,6 +89,7 @@ MCache_Free(MCache *c, void *v, int32 sizeclass, uintptr size)
l->nlist++;
c->size += size;
c->local_alloc -= size;
c->local_objects--;
if(l->nlist >= MaxMCacheListLen) {
// Release a chunk back.
@ -121,11 +123,6 @@ MCache_ReleaseAll(MCache *c)
int32 i;
MCacheList *l;
lock(&mheap);
mstats.heap_alloc += c->local_alloc;
c->local_alloc = 0;
unlock(&mheap);
for(i=0; i<NumSizeClasses; i++) {
l = &c->list[i];
ReleaseN(c, l, l->nlist, i);

148
src/pkg/runtime/mgc0.c
View File

@ -19,6 +19,13 @@ enum {
Debug = 0
};
typedef struct BlockList BlockList;
struct BlockList
{
byte *obj;
uintptr size;
};
extern byte data[];
extern byte etext[];
extern byte end[];
@ -26,6 +33,7 @@ extern byte end[];
static G *fing;
static Finalizer *finq;
static int32 fingwait;
static BlockList *bl, *ebl;
static void runfinq(void);
@ -34,7 +42,7 @@ enum {
};
static void
scanblock(int32 depth, byte *b, int64 n)
scanblock(byte *b, int64 n)
{
int32 off;
void *obj;
@ -42,48 +50,65 @@ scanblock(int32 depth, byte *b, int64 n)
uint32 *refp, ref;
void **vp;
int64 i;
BlockList *w;
if(Debug > 1)
printf("%d scanblock %p %D\n", depth, b, n);
off = (uint32)(uintptr)b & (PtrSize-1);
if(off) {
b += PtrSize - off;
n -= PtrSize - off;
}
w = bl;
w->obj = b;
w->size = n;
w++;
vp = (void**)b;
n /= PtrSize;
for(i=0; i<n; i++) {
obj = vp[i];
if(obj == nil)
continue;
if(mheap.closure_min != nil && mheap.closure_min <= (byte*)obj && (byte*)obj < mheap.closure_max) {
if((((uintptr)obj) & 63) != 0)
continue;
while(w > bl) {
w--;
b = w->obj;
n = w->size;
// Looks like a Native Client closure.
// Actual pointer is pointed at by address in first instruction.
// Embedded pointer starts at byte 2.
// If it is f4f4f4f4 then that space hasn't been
// used for a closure yet (f4 is the HLT instruction).
// See nacl/386/closure.c for more.
void **pp;
pp = *(void***)((byte*)obj+2);
if(pp == (void**)0xf4f4f4f4) // HLT... - not a closure after all
continue;
obj = *pp;
if(Debug > 1)
printf("scanblock %p %D\n", b, n);
off = (uint32)(uintptr)b & (PtrSize-1);
if(off) {
b += PtrSize - off;
n -= PtrSize - off;
}
if(mheap.min <= (byte*)obj && (byte*)obj < mheap.max) {
if(mlookup(obj, &obj, &size, nil, &refp)) {
ref = *refp;
switch(ref & ~RefFlags) {
case RefNone:
if(Debug > 1)
printf("%d found at %p: ", depth, &vp[i]);
*refp = RefSome | (ref & RefFlags);
if(!(ref & RefNoPointers))
scanblock(depth+1, obj, size);
break;
vp = (void**)b;
n /= PtrSize;
for(i=0; i<n; i++) {
obj = vp[i];
if(obj == nil)
continue;
if(mheap.closure_min != nil && mheap.closure_min <= (byte*)obj && (byte*)obj < mheap.closure_max) {
if((((uintptr)obj) & 63) != 0)
continue;
// Looks like a Native Client closure.
// Actual pointer is pointed at by address in first instruction.
// Embedded pointer starts at byte 2.
// If it is f4f4f4f4 then that space hasn't been
// used for a closure yet (f4 is the HLT instruction).
// See nacl/386/closure.c for more.
void **pp;
pp = *(void***)((byte*)obj+2);
if(pp == (void**)0xf4f4f4f4) // HLT... - not a closure after all
continue;
obj = *pp;
}
if(mheap.min <= (byte*)obj && (byte*)obj < mheap.max) {
if(mlookup(obj, &obj, &size, nil, &refp)) {
ref = *refp;
switch(ref & ~RefFlags) {
case RefNone:
if(Debug > 1)
printf("found at %p: ", &vp[i]);
*refp = RefSome | (ref & RefFlags);
if(!(ref & RefNoPointers)) {
if(w >= ebl)
throw("scanblock: garbage collection stack overflow");
w->obj = obj;
w->size = size;
w++;
}
break;
}
}
}
}
@ -104,7 +129,7 @@ scanstack(G *gp)
printf("scanstack %d %p\n", gp->goid, sp);
stk = (Stktop*)gp->stackbase;
while(stk) {
scanblock(0, sp, (byte*)stk - sp);
scanblock(sp, (byte*)stk - sp);
sp = stk->gobuf.sp;
stk = (Stktop*)stk->stackbase;
}
@ -122,19 +147,40 @@ markfin(void *v)
throw("mark - finalizer inconsistency");
// do not mark the finalizer block itself. just mark the things it points at.
scanblock(1, v, size);
scanblock(v, size);
}
static void
mark(void)
{
G *gp;
uintptr blsize, nobj;
// Figure out how big an object stack we need.
// Get a new one if we need more than we have
// or we need significantly less than we have.
nobj = mstats.heap_objects;
if(nobj > ebl - bl || nobj < (ebl-bl)/4) {
if(bl != nil)
SysFree(bl, (byte*)ebl - (byte*)bl);
// While we're allocated a new object stack,
// add 20% headroom and also round up to
// the nearest page boundary, since mmap
// will anyway.
nobj = nobj * 12/10;
blsize = nobj * sizeof *bl;
blsize = (blsize + 4095) & ~4095;
nobj = blsize / sizeof *bl;
bl = SysAlloc(blsize);
ebl = bl + nobj;
}
// mark data+bss.
// skip mheap itself, which has no interesting pointers
// and is mostly zeroed and would not otherwise be paged in.
scanblock(0, data, (byte*)&mheap - data);
scanblock(0, (byte*)(&mheap+1), end - (byte*)(&mheap+1));
scanblock(data, (byte*)&mheap - data);
scanblock((byte*)(&mheap+1), end - (byte*)(&mheap+1));
// mark stacks
for(gp=allg; gp!=nil; gp=gp->alllink) {
@ -276,6 +322,21 @@ stealcache(void)
MCache_ReleaseAll(m->mcache);
}
static void
cachestats(void)
{
M *m;
MCache *c;
for(m=allm; m; m=m->alllink) {
c = m->mcache;
mstats.heap_alloc += c->local_alloc;
c->local_alloc = 0;
mstats.heap_objects += c->local_objects;
c->local_objects = 0;
}
}
void
gc(int32 force)
{
@ -313,6 +374,7 @@ gc(int32 force)
if(mheap.Lock.key != 0)
throw("mheap locked during gc");
if(force || mstats.heap_alloc >= mstats.next_gc) {
cachestats();
mark();
sweep();
stealcache();

12
src/pkg/runtime/mheap.c
View File

@ -60,11 +60,15 @@ MHeap_Alloc(MHeap *h, uintptr npage, int32 sizeclass, int32 acct)
lock(h);
mstats.heap_alloc += m->mcache->local_alloc;
m->mcache->local_alloc = 0;
mstats.heap_objects += m->mcache->local_objects;
m->mcache->local_objects = 0;
s = MHeap_AllocLocked(h, npage, sizeclass);
if(s != nil) {
mstats.heap_inuse += npage<<PageShift;
if(acct)
if(acct) {
mstats.heap_objects++;
mstats.heap_alloc += npage<<PageShift;
}
}
unlock(h);
return s;
@ -240,9 +244,13 @@ MHeap_Free(MHeap *h, MSpan *s, int32 acct)
lock(h);
mstats.heap_alloc += m->mcache->local_alloc;
m->mcache->local_alloc = 0;
mstats.heap_objects += m->mcache->local_objects;
m->mcache->local_objects = 0;
mstats.heap_inuse -= s->npages<<PageShift;
if(acct)
if(acct) {
mstats.heap_alloc -= s->npages<<PageShift;
mstats.heap_objects--;
}
MHeap_FreeLocked(h, s);
unlock(h);
}

4
src/pkg/runtime/nacl/386/sys.s
View File

@ -11,6 +11,7 @@
// http://code.google.com/p/nativeclient/source/browse/trunk/src/native_client/src/trusted/service_runtime/include/bits/nacl_syscalls.h
#define SYS_exit 30
#define SYS_mmap 21
#define SYS_munmap 22
#define SYS_thread_create 80
#define SYS_thread_exit 81
#define SYS_tls_init 82
@ -91,6 +92,9 @@ TEXT ·mmap(SB),7,$24
INT $3
RET
TEXT ·munmap(SB),7,$0
JMP SYSCALL(munmap)
TEXT gettime(SB),7,$32
LEAL 8(SP), BX
MOVL BX, 0(SP)

4
src/pkg/runtime/nacl/mem.c
View File

@ -21,8 +21,6 @@ SysUnused(void *v, uintptr n)
void
SysFree(void *v, uintptr n)
{
USED(v);
USED(n);
// TODO(rsc): call munmap
runtime_munmap(v, n);
}

2
src/pkg/runtime/runtime.h
View File

@ -498,6 +498,7 @@ void notewakeup(Note*);
#define runtime_memclr ·memclr
#define runtime_getcallerpc ·getcallerpc
#define runtime_mmap ·mmap
#define runtime_munmap ·munmap
#define runtime_printslice ·printslice
#define runtime_printbool ·printbool
#define runtime_printfloat ·printfloat
@ -524,6 +525,7 @@ void notewakeup(Note*);
* low level go-called
*/
uint8* runtime_mmap(byte*, uintptr, int32, int32, int32, uint32);
void runtime_munmap(uint8*, uintptr);
void runtime_memclr(byte*, uint32);
void runtime_setcallerpc(void*, void*);
void* runtime_getcallerpc(void*);

19
src/pkg/runtime/tiny/mem.c
View File

@ -8,21 +8,22 @@
// Assume there's an arbitrary amount of memory starting at "end".
// Sizing PC memory is beyond the scope of this demo.
static byte *allocp;
void*
SysAlloc(uintptr ask)
{
static byte *p;
extern byte end[];
byte *q;
if(p == nil) {
p = end;
p += 7 & -(uintptr)p;
if(allocp == nil) {
allocp = end;
allocp += 7 & -(uintptr)allocp;
}
ask += 7 & -ask;
q = p;
p += ask;
q = allocp;
allocp += ask;
·memclr(q, ask);
return q;
}
@ -30,7 +31,11 @@ SysAlloc(uintptr ask)
void
SysFree(void *v, uintptr n)
{
USED(v, n);
// Push pointer back if this is a free
// of the most recent SysAlloc.
n += 7 & -n;
if(allocp == v+n)
allocp -= n;
}
void

14
src/pkg/runtime/windows/mem.c
View File

@ -7,10 +7,18 @@
#include "defs.h"
#include "malloc.h"
enum {
MEM_COMMIT = 0x1000,
MEM_RESERVE = 0x2000,
MEM_RELEASE = 0x8000,
PAGE_EXECUTE_READWRITE = 0x40,
};
void*
SysAlloc(uintptr n)
{
return stdcall(VirtualAlloc, 4, nil, n, 0x3000, 0x40);
return stdcall(VirtualAlloc, 4, nil, n, MEM_COMMIT | MEM_RESERVE, PAGE_EXECUTE_READWRITE);
}
void
@ -23,7 +31,5 @@ SysUnused(void *v, uintptr n)
void
SysFree(void *v, uintptr n)
{
USED(v);
USED(n);
return stdcall(VirtualFree, 3, v, n, MEM_RELEASE);
}