mirror of https://github.com/golang/go.git
1fb4e4de26
This makes compress/flate's version of Snappy diverge from the upstream golang/snappy version, but the latter has a goal of matching C++ snappy output byte-for-byte. Both C++ and the asm version of golang/snappy can use a smaller N for the O(N) zero-initialization of the hash table when the input is small, even if the pure Go golang/snappy algorithm cannot: "var table [tableSize]uint16" zeroes all tableSize elements. For this package, we don't have the match-C++-snappy goal, so we can use a different (constant) hash table size. This is a small win, in terms of throughput and output size, but it also enables us to re-use the (constant size) hash table between encodeBestSpeed calls, avoiding the cost of zero-initializing the hash table altogether. This will be implemented in follow-up commits. This package's benchmarks: name old speed new speed delta EncodeDigitsSpeed1e4-8 72.8MB/s ± 1% 73.5MB/s ± 1% +0.86% (p=0.000 n=10+10) EncodeDigitsSpeed1e5-8 77.5MB/s ± 1% 78.0MB/s ± 0% +0.69% (p=0.000 n=10+10) EncodeDigitsSpeed1e6-8 82.0MB/s ± 1% 82.7MB/s ± 1% +0.85% (p=0.000 n=10+9) EncodeTwainSpeed1e4-8 65.1MB/s ± 1% 65.6MB/s ± 0% +0.78% (p=0.000 n=10+9) EncodeTwainSpeed1e5-8 80.0MB/s ± 0% 80.6MB/s ± 1% +0.66% (p=0.000 n=9+10) EncodeTwainSpeed1e6-8 81.6MB/s ± 1% 82.1MB/s ± 1% +0.55% (p=0.017 n=10+10) Input size in bytes, output size (and time taken) before and after on some larger files: 1073741824 57269781 ( 3183ms) 57269781 ( 3177ms) adresser.001 1000000000 391052000 ( 11071ms) 391051996 ( 11067ms) enwik9 1911399616 378679516 ( 13450ms) 378679514 ( 13079ms) gob-stream 8558382592 3972329193 ( 99962ms) 3972329193 ( 91290ms) rawstudio-mint14.tar 200000000 200015265 ( 776ms) 200015265 ( 774ms) sharnd.out Thanks to Klaus Post for the original suggestion on cl/21021. Change-Id: Ia4c63a8d1b92c67e1765ec5c3c8c69d289d9a6ce Reviewed-on: https://go-review.googlesource.com/22604 Reviewed-by: Russ Cox <rsc@golang.org> |
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| archive | ||
| bufio | ||
| builtin | ||
| bytes | ||
| cmd | ||
| compress | ||
| container | ||
| context | ||
| crypto | ||
| database/sql | ||
| debug | ||
| encoding | ||
| errors | ||
| expvar | ||
| flag | ||
| fmt | ||
| go | ||
| hash | ||
| html | ||
| image | ||
| index/suffixarray | ||
| internal | ||
| io | ||
| log | ||
| math | ||
| mime | ||
| net | ||
| os | ||
| path | ||
| reflect | ||
| regexp | ||
| runtime | ||
| sort | ||
| strconv | ||
| strings | ||
| sync | ||
| syscall | ||
| testing | ||
| text | ||
| time | ||
| unicode | ||
| unsafe | ||
| vendor/golang.org/x/net/http2/hpack | ||
| Make.dist | ||
| all.bash | ||
| all.bat | ||
| all.rc | ||
| androidtest.bash | ||
| bootstrap.bash | ||
| buildall.bash | ||
| clean.bash | ||
| clean.bat | ||
| clean.rc | ||
| cmp.bash | ||
| iostest.bash | ||
| make.bash | ||
| make.bat | ||
| make.rc | ||
| naclmake.bash | ||
| nacltest.bash | ||
| race.bash | ||
| race.bat | ||
| run.bash | ||
| run.bat | ||
| run.rc | ||