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Merge pull request #2538 from senhuang42/monotonicity_test

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Add memory monotonicity test over srcSize
This commit is contained in:
sen
2021-03-22 16:54:34 -04:00
committed by GitHub
parent ebc2dfa821 dff4a0e867
commit c48889f097
2 changed files with 52 additions and 2 deletions
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lib/compress/zstd_compress.c
+10 -2
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@@ -1390,8 +1390,15 @@ size_t ZSTD_estimateCCtxSize_usingCParams(ZSTD_compressionParameters cParams)
static size_t ZSTD_estimateCCtxSize_internal(int compressionLevel)
{
ZSTD_compressionParameters const cParams = ZSTD_getCParams_internal(compressionLevel, ZSTD_CONTENTSIZE_UNKNOWN, 0, ZSTD_cpm_noAttachDict);
return ZSTD_estimateCCtxSize_usingCParams(cParams);
int tier = 0;
size_t largestSize = 0;
static const unsigned long long srcSizeTiers[4] = {16 KB, 128 KB, 256 KB, ZSTD_CONTENTSIZE_UNKNOWN};
for (; tier < 4; ++tier) {
/* Choose the set of cParams for a given level across all srcSizes that give the largest cctxSize */
ZSTD_compressionParameters const cParams = ZSTD_getCParams_internal(compressionLevel, srcSizeTiers[tier], 0, ZSTD_cpm_noAttachDict);
largestSize = MAX(ZSTD_estimateCCtxSize_usingCParams(cParams), largestSize);
}
return largestSize;
}
size_t ZSTD_estimateCCtxSize(int compressionLevel)
@@ -1399,6 +1406,7 @@ size_t ZSTD_estimateCCtxSize(int compressionLevel)
int level;
size_t memBudget = 0;
for (level=MIN(compressionLevel, 1); level<=compressionLevel; level++) {
/* Ensure monotonically increasing memory usage as compression level increases */
size_t const newMB = ZSTD_estimateCCtxSize_internal(level);
if (newMB > memBudget) memBudget = newMB;
}