From: Yann Collet Date: Wed, 28 Jun 2017 22:34:56 +0000 (-0700) Subject: added function to control monotonic memory budget increase of ZSTD_defaultCParameters[0] X-Git-Tag: v1.3.0~1^2~12^2~1 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=813535105b4883183fb7ebffea454944d0dd7552;p=thirdparty%2Fzstd.git added function to control monotonic memory budget increase of ZSTD_defaultCParameters[0] It's a runtime test, based on assert(), played once, on first ZSTD_getCParams() usage, when ZSTD_DEBUG is enabled. --- diff --git a/doc/zstd_manual.html b/doc/zstd_manual.html index 6d524ae32..bb6f0eac9 100644 --- a/doc/zstd_manual.html +++ b/doc/zstd_manual.html @@ -412,9 +412,9 @@ size_t ZSTD_estimateCCtxSize_advanced(ZSTD_compressionParameters cParams); size_t ZSTD_estimateDCtxSize(void);

These functions make it possible to estimate memory usage of a future {D,C}Ctx, before its creation. - The objective is to guide decision before allocation. - ZSTD_estimateCCtxSize() will consider src size to be arbitrarily "large". - If srcSize is known to be small, ZSTD_estimateCCtxSize_advanced() can provide a tighter estimation. + ZSTD_estimateCCtxSize() will provide a budget large for any compression level up to selected one. + It will also consider src size to be arbitrarily "large", which is worst case. + If srcSize is known to always be small, ZSTD_estimateCCtxSize_advanced() can provide a tighter estimation. ZSTD_estimateCCtxSize_advanced() can be used in tandem with ZSTD_getCParams() to create cParams from compressionLevel. Note : CCtx estimation is only correct for single-threaded compression


@@ -423,8 +423,9 @@ size_t ZSTD_estimateDCtxSize(void); size_t ZSTD_estimateCStreamSize_advanced(ZSTD_compressionParameters cParams); size_t ZSTD_estimateDStreamSize(size_t windowSize); size_t ZSTD_estimateDStreamSize_fromFrame(const void* src, size_t srcSize); -

ZSTD_estimateCStreamSize() will consider src size to be arbitrarily "large". - If srcSize is known to be small, ZSTD_estimateCStreamSize_advanced() can provide a tighter estimation. +

ZSTD_estimateCStreamSize() will provide a budget large for any compression level up to selected one. + It will also consider src size to be arbitrarily "large", which is worst case. + If srcSize is known to always be small, ZSTD_estimateCStreamSize_advanced() can provide a tighter estimation. ZSTD_estimateCStreamSize_advanced() can be used in tandem with ZSTD_getCParams() to create cParams from compressionLevel. Note : CStream estimation is only correct for single-threaded compression. ZSTD_DStream memory budget depends on window Size. diff --git a/lib/compress/zstd_compress.c b/lib/compress/zstd_compress.c index c781232c6..c2adc56ab 100644 --- a/lib/compress/zstd_compress.c +++ b/lib/compress/zstd_compress.c @@ -4098,6 +4098,43 @@ static const ZSTD_compressionParameters ZSTD_defaultCParameters[4][ZSTD_MAX_CLEV }, }; +/* This function just controls + * the monotonic memory budget increase of ZSTD_defaultCParameters[0]. + * Run only once, on first ZSTD_getCParams() usage, when ZSTD_DEBUG is enabled + */ +MEM_STATIC void ZSTD_check_compressionLevel_monotonicIncrease_memoryBudget(void) +{ +# define ZSTD_TABLECOST(h,c) ((1<<(h)) + (1<<(c))) +# define ZDCP_FIELD(l,field) (ZSTD_defaultCParameters[0][l].field) +# define ZSTD_CHECK_MONOTONIC_INCREASE_LEVEL(l) { \ + assert(ZDCP_FIELD(l,windowLog) <= ZDCP_FIELD(l+1,windowLog) ); \ + assert(ZSTD_TABLECOST(ZDCP_FIELD(l,hashLog), ZDCP_FIELD(l,chainLog)) <= ZSTD_TABLECOST(ZDCP_FIELD(l+1,hashLog), ZDCP_FIELD(l+1,chainLog)) ); \ + } + + ZSTD_CHECK_MONOTONIC_INCREASE_LEVEL(1); + ZSTD_CHECK_MONOTONIC_INCREASE_LEVEL(2); + ZSTD_CHECK_MONOTONIC_INCREASE_LEVEL(3); + ZSTD_CHECK_MONOTONIC_INCREASE_LEVEL(4); + ZSTD_CHECK_MONOTONIC_INCREASE_LEVEL(5); + ZSTD_CHECK_MONOTONIC_INCREASE_LEVEL(6); + ZSTD_CHECK_MONOTONIC_INCREASE_LEVEL(7); + ZSTD_CHECK_MONOTONIC_INCREASE_LEVEL(8); + ZSTD_CHECK_MONOTONIC_INCREASE_LEVEL(9); + ZSTD_CHECK_MONOTONIC_INCREASE_LEVEL(10); + ZSTD_CHECK_MONOTONIC_INCREASE_LEVEL(11); + ZSTD_CHECK_MONOTONIC_INCREASE_LEVEL(12); + ZSTD_CHECK_MONOTONIC_INCREASE_LEVEL(13); + ZSTD_CHECK_MONOTONIC_INCREASE_LEVEL(14); + ZSTD_CHECK_MONOTONIC_INCREASE_LEVEL(15); + ZSTD_CHECK_MONOTONIC_INCREASE_LEVEL(16); + ZSTD_CHECK_MONOTONIC_INCREASE_LEVEL(17); + ZSTD_CHECK_MONOTONIC_INCREASE_LEVEL(18); + ZSTD_CHECK_MONOTONIC_INCREASE_LEVEL(19); + ZSTD_CHECK_MONOTONIC_INCREASE_LEVEL(20); + ZSTD_CHECK_MONOTONIC_INCREASE_LEVEL(21); + assert(ZSTD_maxCLevel()==22); +} + /*! ZSTD_getCParams() : * @return ZSTD_compressionParameters structure for a selected compression level, `srcSize` and `dictSize`. * Size values are optional, provide 0 if not known or unused */ @@ -4108,6 +4145,15 @@ ZSTD_compressionParameters ZSTD_getCParams(int compressionLevel, unsigned long l U32 const tableID = (rSize <= 256 KB) + (rSize <= 128 KB) + (rSize <= 16 KB); /* intentional underflow for srcSizeHint == 0 */ if (compressionLevel <= 0) compressionLevel = ZSTD_CLEVEL_DEFAULT; /* 0 == default; no negative compressionLevel yet */ if (compressionLevel > ZSTD_MAX_CLEVEL) compressionLevel = ZSTD_MAX_CLEVEL; + +#if defined(ZSTD_DEBUG) && (ZSTD_DEBUG>=1) + static int g_monotonicTest = 1; + if (g_monotonicTest) { + ZSTD_check_compressionLevel_monotonicIncrease_memoryBudget(); + g_monotonicTest=0; + } +#endif + { ZSTD_compressionParameters const cp = ZSTD_defaultCParameters[tableID][compressionLevel]; return ZSTD_adjustCParams_internal(cp, srcSizeHint, dictSize); } } diff --git a/lib/zstd.h b/lib/zstd.h index 08358f0df..75bdb4895 100644 --- a/lib/zstd.h +++ b/lib/zstd.h @@ -496,9 +496,9 @@ ZSTDLIB_API size_t ZSTD_sizeof_DDict(const ZSTD_DDict* ddict); /*! ZSTD_estimate*() : * These functions make it possible to estimate memory usage * of a future {D,C}Ctx, before its creation. - * The objective is to guide decision before allocation. - * ZSTD_estimateCCtxSize() will consider src size to be arbitrarily "large". - * If srcSize is known to be small, ZSTD_estimateCCtxSize_advanced() can provide a tighter estimation. + * ZSTD_estimateCCtxSize() will provide a budget large enough for any compression level up to selected one. + * It will also consider src size to be arbitrarily "large", which is worst case. + * If srcSize is known to always be small, ZSTD_estimateCCtxSize_advanced() can provide a tighter estimation. * ZSTD_estimateCCtxSize_advanced() can be used in tandem with ZSTD_getCParams() to create cParams from compressionLevel. * Note : CCtx estimation is only correct for single-threaded compression */ ZSTDLIB_API size_t ZSTD_estimateCCtxSize(int compressionLevel); @@ -506,8 +506,9 @@ ZSTDLIB_API size_t ZSTD_estimateCCtxSize_advanced(ZSTD_compressionParameters cPa ZSTDLIB_API size_t ZSTD_estimateDCtxSize(void); /*! ZSTD_estimate?StreamSize() : - * ZSTD_estimateCStreamSize() will consider src size to be arbitrarily "large". - * If srcSize is known to be small, ZSTD_estimateCStreamSize_advanced() can provide a tighter estimation. + * ZSTD_estimateCStreamSize() will provide a budget large enough for any compression level up to selected one. + * It will also consider src size to be arbitrarily "large", which is worst case. + * If srcSize is known to always be small, ZSTD_estimateCStreamSize_advanced() can provide a tighter estimation. * ZSTD_estimateCStreamSize_advanced() can be used in tandem with ZSTD_getCParams() to create cParams from compressionLevel. * Note : CStream estimation is only correct for single-threaded compression. * ZSTD_DStream memory budget depends on window Size.