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Track Step Rather than Recalculating (+0.5% Speed)

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This commit is contained in:
W. Felix Handte 2021-09-01 17:50:53 -04:00
parent 258c0623e1
commit 1bdf041071
1 changed files with 14 additions and 1 deletions
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15
lib/compress/zstd_double_fast.c
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@ -70,6 +70,9 @@ size_t ZSTD_compressBlock_doubleFast_singleSegment_generic(
const BYTE* const ilimit = iend - HASH_READ_SIZE; const BYTE* const ilimit = iend - HASH_READ_SIZE;
U32 offset_1=rep[0], offset_2=rep[1]; U32 offset_1=rep[0], offset_2=rep[1];
U32 offsetSaved = 0; U32 offsetSaved = 0;
size_t step = 1;
const size_t kStepIncr = 1 << kSearchStrength;
const BYTE* nextStep = ip + kStepIncr;
DEBUGLOG(5, "ZSTD_compressBlock_doubleFast_singleSegment_generic"); DEBUGLOG(5, "ZSTD_compressBlock_doubleFast_singleSegment_generic");
@ -121,7 +124,14 @@ size_t ZSTD_compressBlock_doubleFast_singleSegment_generic(
} }
} }
ip += ((ip-anchor) >> kSearchStrength) + 1; if (ip >= nextStep) {
PREFETCH_L1(ip + 64);
PREFETCH_L1(ip + 128);
step++;
nextStep += kStepIncr;
}
ip += step;
#if defined(__aarch64__) #if defined(__aarch64__)
PREFETCH_L1(ip+256); PREFETCH_L1(ip+256);
#endif #endif
@ -190,6 +200,9 @@ _match_stored:
anchor = ip; anchor = ip;
continue; /* faster when present ... (?) */ continue; /* faster when present ... (?) */
} } } }
step = 1;
nextStep = ip + kStepIncr;
} /* while (ip < ilimit) */ } /* while (ip < ilimit) */
/* save reps for next block */ /* save reps for next block */