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Cleanup and performance enhancements for mini-lookaside.

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FossilOrigin-Name: 74805668430051032ae9b256c84e252755ee03075fc08293c948675ed40ec280
This commit is contained in:
drh 2019-12-13 15:48:21 +00:00
parent ee5b6dd393
commit e6068027ca
6 changed files with 112 additions and 52 deletions
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18
manifest
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@ -1,5 +1,5 @@
C Merge\sfixes\sfrom\strunk.
D 2019-12-13T12:14:23.880
C Cleanup\sand\sperformance\senhancements\sfor\smini-lookaside.
D 2019-12-13T15:48:21.644
F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@ -491,8 +491,8 @@ F src/in-operator.md 10cd8f4bcd225a32518407c2fb2484089112fd71
F src/insert.c 276463aa7a26ee73958b9f4bcbef4eaec516f22bf6b8d7d2428f39c8dea90840
F src/legacy.c d7874bc885906868cd51e6c2156698f2754f02d9eee1bae2d687323c3ca8e5aa
F src/loadext.c d74f5e7bd51f3c9d283442473eb65aef359664efd6513591c03f01881c4ae2da
F src/main.c 94bf8b6a283914cc8fa8743b3db5350206a4be5cccfd9c84d53409ca5d8bd1c1
F src/malloc.c 02235d039c72102d4bddf203a493c2613164487c70ec84bab679fc30daa883f0
F src/main.c 34d73303ac76015d3c8961f16d49ab44a56cbc998f178b27ca07847db4cf9273
F src/malloc.c d74d986f91ebd6a4a9b2995467f4c13a1fdb57ac87df5bb0a7fa3afe1db72d1d
F src/mem0.c 6a55ebe57c46ca1a7d98da93aaa07f99f1059645
F src/mem1.c c12a42539b1ba105e3707d0e628ad70e611040d8f5e38cf942cee30c867083de
F src/mem2.c f1940d9e91948dd6a908fbb9ce3835c36b5d83c3
@ -532,9 +532,9 @@ F src/shell.c.in 4a3a9e1c11847b1904f2b01d087af1c052f660902755abab457cab1756817de
F src/sqlite.h.in 2a23e8161775253d9cf383c2c6aa559005dc787d350dcb0be67a6c4cc3bd1d19
F src/sqlite3.rc 5121c9e10c3964d5755191c80dd1180c122fc3a8
F src/sqlite3ext.h 72af51aa4e912e14cd495fb6e7fac65f0940db80ed950d90911aff292cc47ce2
F src/sqliteInt.h a036ca4ee94ac0dea82c90b2c902dc84bce187adf75e68284e890bc0c4cd3d95
F src/sqliteInt.h 4948c2046c921461d2021e52ac8cec5b65cd56ab0c58aa7150313abace90153c
F src/sqliteLimit.h 1513bfb7b20378aa0041e7022d04acb73525de35b80b252f1b83fedb4de6a76b
F src/status.c 0fe55b92810509eac821ded2e177e1da944a78cdcdfec7813ad1d6b36d6d667e
F src/status.c baf38f521ac079be616dab1ff13f60c6ce0703c7f0429a65238c695197a56935
F src/table.c b46ad567748f24a326d9de40e5b9659f96ffff34
F src/tclsqlite.c 8cd2600e8de23dff6cdf84d39f46ca57139b061b28f6f80b166bace17d52ab1c
F src/test1.c c654981c1d86ebc90dd23fcc0969e6c85e28112f0acc2e2224a97a2a33e7c42f
@ -1852,7 +1852,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
P bda92d92bf69a73bc6dd498f92578ad6e81111a3f97bc8724d1720e7283a83b6 c1014e80b26131200a115beb86929a8f0ded2dd65b075e47373346c0f170576a
R b2be5daabe2de4420861c8338271e7de
P 9c471195f6d3e4b00e2d0f909b306a4036352082dca5f016a8eece226e82163d
R 40d26fbfedcb39151f8726a7fa468e8a
U drh
Z 5e37344191b5a16624379099587382f5
Z 7742eaad4b11604e1540b9f51bda9209

2
manifest.uuid
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@ -1 +1 @@
9c471195f6d3e4b00e2d0f909b306a4036352082dca5f016a8eece226e82163d
74805668430051032ae9b256c84e252755ee03075fc08293c948675ed40ec280

47
src/main.c
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@ -684,6 +684,8 @@ static int setupLookaside(sqlite3 *db, void *pBuf, int sz, int cnt){
#ifndef SQLITE_OMIT_LOOKASIDE
void *pStart;
sqlite3_int64 szAlloc = sz*(sqlite3_int64)cnt;
int nBig; /* Number of full-size slots */
int nSm; /* Number smaller mini-slots */
if( sqlite3LookasideUsed(db,0)>0 ){
return SQLITE_BUSY;
@ -708,56 +710,69 @@ static int setupLookaside(sqlite3 *db, void *pBuf, int sz, int cnt){
sqlite3BeginBenignMalloc();
pStart = sqlite3Malloc( szAlloc ); /* IMP: R-61949-35727 */
sqlite3EndBenignMalloc();
if( pStart ) cnt = sqlite3MallocSize(pStart)/sz;
if( pStart ) szAlloc = sqlite3MallocSize(pStart);
}else{
pStart = pBuf;
}
#ifndef SQLITE_OMIT_MINI_LOOKASIDE
if( sz>=MINI_SZ*3 ){
nBig = szAlloc/(3*MINI_SZ+sz);
nSm = (szAlloc - sz*nBig)/MINI_SZ;
}else if( sz>=MINI_SZ*2 ){
nBig = szAlloc/(MINI_SZ+sz);
nSm = (szAlloc - sz*nBig)/MINI_SZ;
}else
#endif /* SQLITE_OMIT_MINI_LOOKASIDE */
if( sz>0 ){
nBig = szAlloc/sz;
nSm = 0;
}else{
nBig = nSm = 0;
}
db->lookaside.pStart = pStart;
db->lookaside.pInit = 0;
db->lookaside.pFree = 0;
#ifndef SQLITE_OMIT_MINI_LOOKASIDE
db->lookaside.pMiniInit = 0;
db->lookaside.pMiniFree = 0;
/* The arithmetic below causes the number of large lookaside slots to be 1/3
** the number of mini slots, based on the observation that 75% of allocations
** are <= MINI_SZ bytes.
*/
cnt = szAlloc/(3*MINI_SZ+sz);
#endif
db->lookaside.sz = (u16)sz;
db->lookaside.szTrue = (u16)sz;
if( pStart ){
int i;
LookasideSlot *p;
assert( sz > (int)sizeof(LookasideSlot*) );
db->lookaside.nSlot = cnt;
p = (LookasideSlot*)pStart;
for(i=cnt-1; i>=0; i--){
for(i=0; i<nBig; i++){
p->pNext = db->lookaside.pInit;
db->lookaside.pInit = p;
p = (LookasideSlot*)&((u8*)p)[sz];
}
#ifndef SQLITE_OMIT_MINI_LOOKASIDE
db->lookaside.pMiniInit = 0;
db->lookaside.pMiniFree = 0;
db->lookaside.pMiddle = p;
/* Fill the remainder of the buffer with mini slots */
while(p<=(LookasideSlot*)&((u8*)pStart)[szAlloc-MINI_SZ]){
for(i=0; i<nSm; i++){
p->pNext = db->lookaside.pMiniInit;
db->lookaside.pMiniInit = p;
db->lookaside.nSlot++;
p = (LookasideSlot*)&((u8*)p)[MINI_SZ];
}
#endif
#endif /* SQLITE_OMIT_MINI_LOOKASIDE */
assert( ((uptr)p)<=szAlloc + (uptr)pStart );
db->lookaside.pEnd = p;
db->lookaside.bDisable = 0;
db->lookaside.bMalloced = pBuf==0 ?1:0;
db->lookaside.nSlot = nBig+nSm;
}else{
db->lookaside.pStart = db;
#ifndef SQLITE_OMIT_MINI_LOOKASIDE
db->lookaside.pMiniInit = 0;
db->lookaside.pMiniFree = 0;
db->lookaside.pMiddle = db;
#endif /* SQLITE_OMIT_MINI_LOOKASIDE */
db->lookaside.pEnd = db;
db->lookaside.bDisable = 1;
db->lookaside.sz = 0;
db->lookaside.bMalloced = 0;
db->lookaside.nSlot = 0;
}
assert( sqlite3LookasideUsed(db,0)==0 );
#endif /* SQLITE_OMIT_LOOKASIDE */
return SQLITE_OK;
}

65
src/malloc.c
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@ -341,8 +341,8 @@ static int lookasideMallocSize(sqlite3 *db, void *p){
}
int sqlite3DbMallocSize(sqlite3 *db, void *p){
assert( p!=0 );
if( db==0 || !isLookaside(db,p) ){
#ifdef SQLITE_DEBUG
if( db==0 || !isLookaside(db,p) ){
if( db==0 ){
assert( sqlite3MemdebugNoType(p, (u8)~MEMTYPE_HEAP) );
assert( sqlite3MemdebugHasType(p, MEMTYPE_HEAP) );
@ -350,12 +350,23 @@ int sqlite3DbMallocSize(sqlite3 *db, void *p){
assert( sqlite3MemdebugHasType(p, (MEMTYPE_LOOKASIDE|MEMTYPE_HEAP)) );
assert( sqlite3MemdebugNoType(p, (u8)~(MEMTYPE_LOOKASIDE|MEMTYPE_HEAP)) );
}
#endif
return sqlite3GlobalConfig.m.xSize(p);
}else{
assert( sqlite3_mutex_held(db->mutex) );
return lookasideMallocSize(db, p);
}
#endif
if( db ){
if( ((uptr)p)<(uptr)(db->lookaside.pEnd) ){
#ifndef SQLITE_OMIT_MINI_LOOKASIDE
if( ((uptr)p)>=(uptr)(db->lookaside.pMiddle) ){
assert( sqlite3_mutex_held(db->mutex) );
return MINI_SZ;
}
#endif
if( ((uptr)p)>=(uptr)(db->lookaside.pStart) ){
assert( sqlite3_mutex_held(db->mutex) );
return db->lookaside.szTrue;
}
}
}
return sqlite3GlobalConfig.m.xSize(p);
}
sqlite3_uint64 sqlite3_msize(void *p){
assert( sqlite3MemdebugNoType(p, (u8)~MEMTYPE_HEAP) );
@ -402,26 +413,27 @@ void sqlite3DbFreeNN(sqlite3 *db, void *p){
measureAllocationSize(db, p);
return;
}
if( isLookaside(db, p) ){
LookasideSlot *pBuf = (LookasideSlot*)p;
if( ((uptr)p)<(uptr)(db->lookaside.pEnd) ){
#ifndef SQLITE_OMIT_MINI_LOOKASIDE
if( p>=db->lookaside.pMiddle ){
# ifdef SQLITE_DEBUG
/* Trash all content in the buffer being freed */
memset(p, 0xaa, MINI_SZ);
# endif
if( ((uptr)p)>=(uptr)(db->lookaside.pMiddle) ){
LookasideSlot *pBuf = (LookasideSlot*)p;
#ifdef SQLITE_DEBUG
memset(p, 0xaa, MINI_SZ); /* Trash freed content */
#endif
pBuf->pNext = db->lookaside.pMiniFree;
db->lookaside.pMiniFree = pBuf;
return;
}
#endif
#endif /* SQLITE_OMIT_MINI_LOOKASIDE */
if( ((uptr)p)>=(uptr)(db->lookaside.pStart) ){
LookasideSlot *pBuf = (LookasideSlot*)p;
#ifdef SQLITE_DEBUG
/* Trash all content in the buffer being freed */
memset(p, 0xaa, db->lookaside.szTrue);
memset(p, 0xaa, db->lookaside.szTrue); /* Trash freed content */
#endif
pBuf->pNext = db->lookaside.pFree;
db->lookaside.pFree = pBuf;
return;
pBuf->pNext = db->lookaside.pFree;
db->lookaside.pFree = pBuf;
return;
}
}
}
assert( sqlite3MemdebugHasType(p, (MEMTYPE_LOOKASIDE|MEMTYPE_HEAP)) );
@ -585,7 +597,7 @@ void *sqlite3DbMallocRawNN(sqlite3 *db, u64 n){
}
return dbMallocRawFinish(db, n);
}
# ifndef SQLITE_OMIT_MINI_LOOKASIDE
#ifndef SQLITE_OMIT_MINI_LOOKASIDE
if( n<=MINI_SZ ){
if( (pBuf = db->lookaside.pMiniFree)!=0 ){
db->lookaside.pMiniFree = pBuf->pNext;
@ -597,7 +609,7 @@ void *sqlite3DbMallocRawNN(sqlite3 *db, u64 n){
return (void*)pBuf;
}
}
# endif
#endif
if( (pBuf = db->lookaside.pFree)!=0 ){
db->lookaside.pFree = pBuf->pNext;
db->lookaside.anStat[0]++;
@ -631,7 +643,16 @@ void *sqlite3DbRealloc(sqlite3 *db, void *p, u64 n){
assert( db!=0 );
if( p==0 ) return sqlite3DbMallocRawNN(db, n);
assert( sqlite3_mutex_held(db->mutex) );
if( isLookaside(db,p) && n<lookasideMallocSize(db, p) ) return p;
if( ((uptr)p)<(uptr)db->lookaside.pEnd ){
#ifndef SQLITE_OMIT_MINI_LOOKASIDE
if( ((uptr)p)>=(uptr)db->lookaside.pMiddle ){
if( n<=MINI_SZ ) return p;
}else
#endif
if( ((uptr)p)>=(uptr)db->lookaside.pStart ){
if( n<=db->lookaside.szTrue ) return p;
}
}
return dbReallocFinish(db, p, n);
}
static SQLITE_NOINLINE void *dbReallocFinish(sqlite3 *db, void *p, u64 n){

30
src/sqliteInt.h
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@ -1277,6 +1277,25 @@ struct Schema {
** disables lookaside without adding a new test for the bDisable flag
** in a performance-critical path. sz should be set by to szTrue whenever
** bDisable changes back to zero.
**
** Lookaside buffers are initially held on the pInit list. As they are
** used and freed, they are added back to the pFree list. New allocations
** come off of pFree first, then pInit as a fallback. This dual-list
** allows use to compute a high-water mark - the maximum number of allocations
** outstanding at any point in the past - by subtracting the number of
** allocations on the pInit list from the total number of allocations.
**
** Enhancement on 2019-12-12: Mini-lookaside
** The default lookaside configuration is 100 slots of 1200 bytes each.
** The larger slot sizes are important for performance, but they waste
** a lot of space, as most lookaside allocations are less than 128 bytes.
** The mini-lookaside enhancement breaks up the lookaside allocation into
** two pools: One of 128-byte slots and the other of the default size
** (1200-byte) slots. Allocations are filled from the mini-pool first,
** failing over to the full-size pool if that does not work. Thus more
** lookaside slots are available while also using less memory.
** This enhancement can be omitted by compiling with
** SQLITE_OMIT_MINI_LOOKASIDE.
*/
struct Lookaside {
u32 bDisable; /* Only operate the lookaside when zero */
@ -1290,8 +1309,9 @@ struct Lookaside {
#ifndef SQLITE_OMIT_MINI_LOOKASIDE
LookasideSlot *pMiniInit; /* List of mini buffers not prediously used */
LookasideSlot *pMiniFree; /* List of available mini buffers */
void *pMiddle; /* An address between the fullsize and mini buffers */
#endif
void *pMiddle; /* First byte past end of full-size buffers and
** the first byte of mini-buffers */
#endif /* SQLITE_OMIT_MINI_LOOKASIDE */
void *pStart; /* First byte of available memory space */
void *pEnd; /* First byte past end of available space */
};
@ -1304,7 +1324,11 @@ struct LookasideSlot {
db->lookaside.sz=db->lookaside.bDisable?0:db->lookaside.szTrue
/* Size of the MINI lookside allocation */
#define MINI_SZ 128
#ifdef SQLITE_OMIT_MINI_LOOKASIDE
# define MINI_SZ 0
#else
# define MINI_SZ 128
#endif
/*
** A hash table for built-in function definitions. (Application-defined

2
src/status.c
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@ -191,7 +191,7 @@ int sqlite3LookasideUsed(sqlite3 *db, int *pHighwater){
#ifndef SQLITE_OMIT_MINI_LOOKASIDE
nInit += countLookasideSlots(db->lookaside.pMiniInit);
nFree += countLookasideSlots(db->lookaside.pMiniFree);
#endif
#endif /* SQLITE_OMIT_MINI_LOOKASIDE */
if( pHighwater ) *pHighwater = db->lookaside.nSlot - nInit;
return db->lookaside.nSlot - (nInit+nFree);
}