ddidderr/zstd-rs
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Changed nbThreads for nbWorkers

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This makes it easier to explain that nbWorkers=0 --> single-threaded mode,
while nbWorkers=1 --> asynchronous mode (one mode thread on top of the "main" caller thread).
No need for an additional asynchronous mode flag.
nbWorkers>=2 works the same as nbThreads>=2 previously.
This commit is contained in:
Yann Collet
2018-02-01 19:29:30 -08:00
parent 4b6a94f0cc
commit 209df52ba2
15 changed files with 165 additions and 183 deletions
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lib/zstd.h
+13 -17
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@@ -506,7 +506,7 @@ ZSTDLIB_API size_t ZSTD_sizeof_DDict(const ZSTD_DDict* ddict);
* It will also consider src size to be arbitrarily "large", which is worst case.
* If srcSize is known to always be small, ZSTD_estimateCCtxSize_usingCParams() can provide a tighter estimation.
* ZSTD_estimateCCtxSize_usingCParams() can be used in tandem with ZSTD_getCParams() to create cParams from compressionLevel.
* ZSTD_estimateCCtxSize_usingCCtxParams() can be used in tandem with ZSTD_CCtxParam_setParameter(). Only single-threaded compression is supported. This function will return an error code if ZSTD_p_nbThreads is > 1.
* ZSTD_estimateCCtxSize_usingCCtxParams() can be used in tandem with ZSTD_CCtxParam_setParameter(). Only single-threaded compression is supported. This function will return an error code if ZSTD_p_nbWorkers is >= 1.
* Note : CCtx size estimation is only correct for single-threaded compression. */
ZSTDLIB_API size_t ZSTD_estimateCCtxSize(int compressionLevel);
ZSTDLIB_API size_t ZSTD_estimateCCtxSize_usingCParams(ZSTD_compressionParameters cParams);
@@ -518,7 +518,7 @@ ZSTDLIB_API size_t ZSTD_estimateDCtxSize(void);
* It will also consider src size to be arbitrarily "large", which is worst case.
* If srcSize is known to always be small, ZSTD_estimateCStreamSize_usingCParams() can provide a tighter estimation.
* ZSTD_estimateCStreamSize_usingCParams() can be used in tandem with ZSTD_getCParams() to create cParams from compressionLevel.
* ZSTD_estimateCStreamSize_usingCCtxParams() can be used in tandem with ZSTD_CCtxParam_setParameter(). Only single-threaded compression is supported. This function will return an error code if ZSTD_p_nbThreads is set to a value > 1.
* ZSTD_estimateCStreamSize_usingCCtxParams() can be used in tandem with ZSTD_CCtxParam_setParameter(). Only single-threaded compression is supported. This function will return an error code if ZSTD_p_nbWorkers is >= 1.
* Note : CStream size estimation is only correct for single-threaded compression.
* ZSTD_DStream memory budget depends on window Size.
* This information can be passed manually, using ZSTD_estimateDStreamSize,
@@ -992,18 +992,13 @@ typedef enum {
/* multi-threading parameters */
/* These parameters are only useful if multi-threading is enabled (ZSTD_MULTITHREAD).
* They return an error otherwise. */
ZSTD_p_nbThreads=400, /* Select how many threads a compression job can spawn (default:1)
* More threads improve speed, but also increase memory usage.
* Can only receive a value > 1 if ZSTD_MULTITHREAD is enabled.
* Special: value 0 means "do not change nbThreads" */
ZSTD_p_nonBlockingMode, /* Single thread mode is by default "blocking" :
* it finishes its job as much as possible, and only then gives back control to caller.
* In contrast, multi-thread is by default "non-blocking" :
* it takes some input, flush some output if available, and immediately gives back control to caller.
* Compression work is performed in parallel, within worker threads.
* (note : a strong exception to this rule is when first job is called with ZSTD_e_end : it becomes blocking)
* Setting this parameter to 1 will enforce non-blocking mode even when only 1 thread is selected.
* It allows the caller to do other tasks while the worker thread compresses in parallel. */
ZSTD_p_nbWorkers=400, /* Select how many threads will be spawned to compress in parallel.
* When nbWorkers >= 1, triggers asynchronous mode :
* ZSTD_compress_generic() consumes some input, flush some output if possible, and immediately gives back control to caller,
* while compression work is performed in parallel, within worker threads.
* (note : a strong exception to this rule is when first invocation sets ZSTD_e_end : it becomes a blocking call).
* More workers improve speed, but also increase memory usage.
* Default value is `0`, aka "single-threaded mode" : no worker is spawned, compression is performed inside Caller's thread, all invocations are blocking */
ZSTD_p_jobSize, /* Size of a compression job. This value is only enforced in streaming (non-blocking) mode.
* Each compression job is completed in parallel, so indirectly controls the nb of active threads.
* 0 means default, which is dynamically determined based on compression parameters.
@@ -1231,9 +1226,10 @@ ZSTDLIB_API size_t ZSTD_CCtxParam_setParameter(ZSTD_CCtx_params* params, ZSTD_cP
/*! ZSTD_CCtx_setParametersUsingCCtxParams() :
* Apply a set of ZSTD_CCtx_params to the compression context.
* This must be done before the dictionary is loaded.
* The pledgedSrcSize is treated as unknown.
* Multithreading parameters are applied only if nbThreads > 1.
* This can be done even after compression is started,
* if nbWorkers==0, this will have no impact until a new compression is started.
* if nbWorkers>=1, new parameters will be picked up at next job,
* with a few restrictions (windowLog, pledgedSrcSize, nbWorkers, jobSize, and overlapLog are not updated).
*/
ZSTDLIB_API size_t ZSTD_CCtx_setParametersUsingCCtxParams(
ZSTD_CCtx* cctx, const ZSTD_CCtx_params* params);