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Overview
| Comment: | Avoid unnecessary mutex usage in pcache1, for a significant speedup. |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | faster-pcache1-fetch |
| Files: | files | file ages | folders |
| SHA1: |
dcf4fb8d764611de60afea27cda0a854 |
| User & Date: | drh 2015-06-13 11:10:55 |
Context
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2015-06-13
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| 11:19 | Omit mutex calls in pcache1 when the mutex is NULL, for a significant performance improvement. (check-in: caf8f574 user: drh tags: trunk) | |
| 11:10 | Avoid unnecessary mutex usage in pcache1, for a significant speedup. (Closed-Leaf check-in: dcf4fb8d user: drh tags: faster-pcache1-fetch) | |
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2015-06-12
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| 13:49 | Add a fast-path implementation of pcache1Fetch() for the common case of separate caches that do not use a mutex. (check-in: 760700ed user: drh tags: faster-pcache1-fetch) | |
Changes
Changes to src/pcache1.c.
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** compiling for systems that do not support real WSD. */ #define pcache1 (GLOBAL(struct PCacheGlobal, pcache1_g)) /* ** Macros to enter and leave the PCache LRU mutex. */ #define pcache1EnterMutex(X) sqlite3_mutex_enter((X)->mutex) #define pcache1LeaveMutex(X) sqlite3_mutex_leave((X)->mutex) /******************************************************************************/ /******** Page Allocation/SQLITE_CONFIG_PCACHE Related Functions **************/ /* ** This function is called during initialization if a static buffer is ** supplied to use for the page-cache by passing the SQLITE_CONFIG_PAGECACHE ................................................................................ /* ** Implementation of the sqlite3_pcache.xInit method. */ static int pcache1Init(void *NotUsed){ UNUSED_PARAMETER(NotUsed); assert( pcache1.isInit==0 ); memset(&pcache1, 0, sizeof(pcache1)); if( sqlite3GlobalConfig.bCoreMutex ){ pcache1.grp.mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_LRU); pcache1.mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_PMEM); } pcache1.grp.mxPinned = 10; pcache1.isInit = 1; return SQLITE_OK; } /* ** Implementation of the sqlite3_pcache.xShutdown method. ................................................................................ }else if( createFlag ){ /* Steps 3, 4, and 5 implemented by this subroutine */ return pcache1FetchStage2(pCache, iKey, createFlag); }else{ return 0; } } static PgHdr1 *pcache1FetchWithMutex( sqlite3_pcache *p, unsigned int iKey, int createFlag ){ PCache1 *pCache = (PCache1 *)p; PgHdr1 *pPage; ................................................................................ pcache1EnterMutex(pCache->pGroup); pPage = pcache1FetchNoMutex(p, iKey, createFlag); assert( pPage==0 || pCache->iMaxKey>=iKey ); pcache1LeaveMutex(pCache->pGroup); return pPage; } static sqlite3_pcache_page *pcache1Fetch( sqlite3_pcache *p, unsigned int iKey, int createFlag ){ PCache1 *pCache = (PCache1 *)p; assert( offsetof(PgHdr1,page)==0 ); assert( pCache->bPurgeable || createFlag!=1 ); assert( pCache->bPurgeable || pCache->nMin==0 ); assert( pCache->bPurgeable==0 || pCache->nMin==10 ); assert( pCache->nMin==0 || pCache->bPurgeable ); assert( pCache->nHash>0 ); if( pCache->pGroup->mutex ){ return (sqlite3_pcache_page*)pcache1FetchWithMutex(p, iKey, createFlag); }else{ return (sqlite3_pcache_page*)pcache1FetchNoMutex(p, iKey, createFlag); } } /* ** Implementation of the sqlite3_pcache.xUnpin method. |
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** compiling for systems that do not support real WSD. */ #define pcache1 (GLOBAL(struct PCacheGlobal, pcache1_g)) /* ** Macros to enter and leave the PCache LRU mutex. */ #if !defined(SQLITE_ENABLE_MEMORY_MANAGEMENT) || SQLITE_THREADSAFE==0 # define pcache1EnterMutex(X) assert((X)->mutex==0) # define pcache1LeaveMutex(X) assert((X)->mutex==0) # define PCACHE1_MIGHT_USE_GROUP_MUTEX 0 #else # define pcache1EnterMutex(X) sqlite3_mutex_enter((X)->mutex) # define pcache1LeaveMutex(X) sqlite3_mutex_leave((X)->mutex) # define PCACHE1_MIGHT_USE_GROUP_MUTEX 1 #endif /******************************************************************************/ /******** Page Allocation/SQLITE_CONFIG_PCACHE Related Functions **************/ /* ** This function is called during initialization if a static buffer is ** supplied to use for the page-cache by passing the SQLITE_CONFIG_PAGECACHE ................................................................................ /* ** Implementation of the sqlite3_pcache.xInit method. */ static int pcache1Init(void *NotUsed){ UNUSED_PARAMETER(NotUsed); assert( pcache1.isInit==0 ); memset(&pcache1, 0, sizeof(pcache1)); #if SQLITE_THREADSAFE if( sqlite3GlobalConfig.bCoreMutex ){ pcache1.grp.mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_LRU); pcache1.mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_PMEM); } #endif pcache1.grp.mxPinned = 10; pcache1.isInit = 1; return SQLITE_OK; } /* ** Implementation of the sqlite3_pcache.xShutdown method. ................................................................................ }else if( createFlag ){ /* Steps 3, 4, and 5 implemented by this subroutine */ return pcache1FetchStage2(pCache, iKey, createFlag); }else{ return 0; } } #if PCACHE1_MIGHT_USE_GROUP_MUTEX static PgHdr1 *pcache1FetchWithMutex( sqlite3_pcache *p, unsigned int iKey, int createFlag ){ PCache1 *pCache = (PCache1 *)p; PgHdr1 *pPage; ................................................................................ pcache1EnterMutex(pCache->pGroup); pPage = pcache1FetchNoMutex(p, iKey, createFlag); assert( pPage==0 || pCache->iMaxKey>=iKey ); pcache1LeaveMutex(pCache->pGroup); return pPage; } #endif static sqlite3_pcache_page *pcache1Fetch( sqlite3_pcache *p, unsigned int iKey, int createFlag ){ #if PCACHE1_MIGHT_USE_GROUP_MUTEX || defined(SQLITE_DEBUG) PCache1 *pCache = (PCache1 *)p; #endif assert( offsetof(PgHdr1,page)==0 ); assert( pCache->bPurgeable || createFlag!=1 ); assert( pCache->bPurgeable || pCache->nMin==0 ); assert( pCache->bPurgeable==0 || pCache->nMin==10 ); assert( pCache->nMin==0 || pCache->bPurgeable ); assert( pCache->nHash>0 ); #if PCACHE1_MIGHT_USE_GROUP_MUTEX if( pCache->pGroup->mutex ){ return (sqlite3_pcache_page*)pcache1FetchWithMutex(p, iKey, createFlag); }else #endif { return (sqlite3_pcache_page*)pcache1FetchNoMutex(p, iKey, createFlag); } } /* ** Implementation of the sqlite3_pcache.xUnpin method. |