mirror of https://github.com/google/snappy.git
21 Commits
| Author | SHA1 | Message | Date |
|---|---|---|---|
Steinar H. Gunderson
|
11ccdfb868 |
Sync with various Google-internal changes.
Should not mean much for the open-source version. |
|
|
snappy.mirrorbot@gmail.com
|
7c3c01df77 |
When we compare the number of bytes produced with the offset for a
backreference, make the signedness of the bytes produced clear, by sticking it into a size_t. This avoids a signed/unsigned compare warning from MSVC (public issue 71), and also is slightly clearer. Since the line is now so long the explanatory comment about the -1u trick has to go somewhere else anyway, I used the opportunity to explain it in slightly more detail. This is a purely stylistic change; the emitted assembler from GCC is identical. R=jeff git-svn-id: https://snappy.googlecode.com/svn/trunk@79 03e5f5b5-db94-4691-08a0-1a8bf15f6143 |
|
|
snappy.mirrorbot@gmail.com
|
2f0aaf8631 |
In the fast path for decompressing literals, instead of checking
whether there's 16 bytes free and then checking right afterwards (when having subtracted the literal size) that there are now 5 bytes free, just check once for 21 bytes. This skips a compare and a branch; although it is easily predictable, it is still a few cycles on a fast path that we would like to get rid of. Benchmarking this yields very confusing results. On open-source GCC 4.8.1 on Haswell, we get exactly the expected results; the benchmarks where we hit the fast path for literals (in particular the two HTML benchmarks and the protobuf benchmark) give very nice speedups, and the others are not really affected. However, benchmarks with Google's GCC branch on other hardware is much less clear. It seems that we have a weak loss in some cases (and the win for the “typical” win cases are not nearly as clear), but that it depends on microarchitecture and plain luck in how we run the benchmark. Looking at the generated assembler, it seems that the removal of the if causes other large-scale changes in how the function is laid out, which makes it likely that this is just bad luck. Thus, we should keep this change, even though its exact current impact is unclear; it's a sensible change per se, and dropping it on the basis of microoptimization for a given compiler (or even branch of a compiler) would seem like a bad strategy in the long run. Microbenchmark results (all in 64-bit, opt mode): Nehalem, Google GCC: Benchmark Base (ns) New (ns) Improvement ------------------------------------------------------------------------------ BM_UFlat/0 76747 75591 1.3GB/s html +1.5% BM_UFlat/1 765756 757040 886.3MB/s urls +1.2% BM_UFlat/2 10867 10893 10.9GB/s jpg -0.2% BM_UFlat/3 124 131 1.4GB/s jpg_200 -5.3% BM_UFlat/4 31663 31596 2.8GB/s pdf +0.2% BM_UFlat/5 314162 308176 1.2GB/s html4 +1.9% BM_UFlat/6 29668 29746 790.6MB/s cp -0.3% BM_UFlat/7 12958 13386 796.4MB/s c -3.2% BM_UFlat/8 3596 3682 966.0MB/s lsp -2.3% BM_UFlat/9 1019193 1033493 953.3MB/s xls -1.4% BM_UFlat/10 239 247 775.3MB/s xls_200 -3.2% BM_UFlat/11 236411 240271 606.9MB/s txt1 -1.6% BM_UFlat/12 206639 209768 571.2MB/s txt2 -1.5% BM_UFlat/13 627803 635722 641.4MB/s txt3 -1.2% BM_UFlat/14 845932 857816 538.2MB/s txt4 -1.4% BM_UFlat/15 402107 391670 1.2GB/s bin +2.7% BM_UFlat/16 283 279 683.6MB/s bin_200 +1.4% BM_UFlat/17 46070 46815 781.5MB/s sum -1.6% BM_UFlat/18 5053 5163 782.0MB/s man -2.1% BM_UFlat/19 79721 76581 1.4GB/s pb +4.1% BM_UFlat/20 251158 252330 697.5MB/s gaviota -0.5% Sum of all benchmarks 4966150 4980396 -0.3% Sandy Bridge, Google GCC: Benchmark Base (ns) New (ns) Improvement ------------------------------------------------------------------------------ BM_UFlat/0 42850 42182 2.3GB/s html +1.6% BM_UFlat/1 525660 515816 1.3GB/s urls +1.9% BM_UFlat/2 7173 7283 16.3GB/s jpg -1.5% BM_UFlat/3 92 91 2.1GB/s jpg_200 +1.1% BM_UFlat/4 15147 14872 5.9GB/s pdf +1.8% BM_UFlat/5 199936 192116 2.0GB/s html4 +4.1% BM_UFlat/6 12796 12443 1.8GB/s cp +2.8% BM_UFlat/7 6588 6400 1.6GB/s c +2.9% BM_UFlat/8 2010 1951 1.8GB/s lsp +3.0% BM_UFlat/9 761124 763049 1.3GB/s xls -0.3% BM_UFlat/10 186 189 1016.1MB/s xls_200 -1.6% BM_UFlat/11 159354 158460 918.6MB/s txt1 +0.6% BM_UFlat/12 139732 139950 856.1MB/s txt2 -0.2% BM_UFlat/13 429917 425027 961.7MB/s txt3 +1.2% BM_UFlat/14 585255 587324 785.8MB/s txt4 -0.4% BM_UFlat/15 276186 266173 1.8GB/s bin +3.8% BM_UFlat/16 205 207 925.5MB/s bin_200 -1.0% BM_UFlat/17 24925 24935 1.4GB/s sum -0.0% BM_UFlat/18 2632 2576 1.5GB/s man +2.2% BM_UFlat/19 40546 39108 2.8GB/s pb +3.7% BM_UFlat/20 175803 168209 1048.9MB/s gaviota +4.5% Sum of all benchmarks 3408117 3368361 +1.2% Haswell, upstream GCC 4.8.1: Benchmark Base (ns) New (ns) Improvement ------------------------------------------------------------------------------ BM_UFlat/0 46308 40641 2.3GB/s html +13.9% BM_UFlat/1 513385 514706 1.3GB/s urls -0.3% BM_UFlat/2 6197 6151 19.2GB/s jpg +0.7% BM_UFlat/3 61 61 3.0GB/s jpg_200 +0.0% BM_UFlat/4 13551 13429 6.5GB/s pdf +0.9% BM_UFlat/5 198317 190243 2.0GB/s html4 +4.2% BM_UFlat/6 14768 12560 1.8GB/s cp +17.6% BM_UFlat/7 6453 6447 1.6GB/s c +0.1% BM_UFlat/8 1991 1980 1.8GB/s lsp +0.6% BM_UFlat/9 766947 770424 1.2GB/s xls -0.5% BM_UFlat/10 170 169 1.1GB/s xls_200 +0.6% BM_UFlat/11 164350 163554 888.7MB/s txt1 +0.5% BM_UFlat/12 145444 143830 832.1MB/s txt2 +1.1% BM_UFlat/13 437849 438413 929.2MB/s txt3 -0.1% BM_UFlat/14 603587 605309 759.8MB/s txt4 -0.3% BM_UFlat/15 249799 248067 1.9GB/s bin +0.7% BM_UFlat/16 191 188 1011.4MB/s bin_200 +1.6% BM_UFlat/17 26064 24778 1.4GB/s sum +5.2% BM_UFlat/18 2620 2601 1.5GB/s man +0.7% BM_UFlat/19 44551 37373 3.0GB/s pb +19.2% BM_UFlat/20 165408 164584 1.0GB/s gaviota +0.5% Sum of all benchmarks 3408011 3385508 +0.7% git-svn-id: https://snappy.googlecode.com/svn/trunk@78 03e5f5b5-db94-4691-08a0-1a8bf15f6143 |
|
|
snappy.mirrorbot@gmail.com
|
062bf544a6 |
Make the two IncrementalCopy* functions take in an ssize_t instead of a len,
in order to avoid having to do 32-to-64-bit signed conversions on a hot path during decompression. (Also fixes some MSVC warnings, mentioned in public issue 75, but more of those remain.) They cannot be size_t because we expect them to go negative and test for that. This saves a few movzwl instructions, yielding ~2% speedup in decompression. Sandy Bridge: Benchmark Base (ns) New (ns) Improvement ------------------------------------------------------------------------------------------------- BM_UFlat/0 48009 41283 2.3GB/s html +16.3% BM_UFlat/1 531274 513419 1.3GB/s urls +3.5% BM_UFlat/2 7378 7062 16.8GB/s jpg +4.5% BM_UFlat/3 92 92 2.0GB/s jpg_200 +0.0% BM_UFlat/4 15057 14974 5.9GB/s pdf +0.6% BM_UFlat/5 204323 193140 2.0GB/s html4 +5.8% BM_UFlat/6 13282 12611 1.8GB/s cp +5.3% BM_UFlat/7 6511 6504 1.6GB/s c +0.1% BM_UFlat/8 2014 2030 1.7GB/s lsp -0.8% BM_UFlat/9 775909 768336 1.3GB/s xls +1.0% BM_UFlat/10 182 184 1043.2MB/s xls_200 -1.1% BM_UFlat/11 167352 161630 901.2MB/s txt1 +3.5% BM_UFlat/12 147393 142246 842.8MB/s txt2 +3.6% BM_UFlat/13 449960 432853 944.4MB/s txt3 +4.0% BM_UFlat/14 620497 594845 775.9MB/s txt4 +4.3% BM_UFlat/15 265610 267356 1.8GB/s bin -0.7% BM_UFlat/16 206 205 932.7MB/s bin_200 +0.5% BM_UFlat/17 25561 24730 1.4GB/s sum +3.4% BM_UFlat/18 2620 2644 1.5GB/s man -0.9% BM_UFlat/19 45766 38589 2.9GB/s pb +18.6% BM_UFlat/20 171107 169832 1039.5MB/s gaviota +0.8% Sum of all benchmarks 3500103 3394565 +3.1% Westmere: Benchmark Base (ns) New (ns) Improvement ------------------------------------------------------------------------------------------------- BM_UFlat/0 72624 71526 1.3GB/s html +1.5% BM_UFlat/1 735821 722917 930.8MB/s urls +1.8% BM_UFlat/2 10450 10172 11.7GB/s jpg +2.7% BM_UFlat/3 117 117 1.6GB/s jpg_200 +0.0% BM_UFlat/4 29817 29648 3.0GB/s pdf +0.6% BM_UFlat/5 297126 293073 1.3GB/s html4 +1.4% BM_UFlat/6 28252 27994 842.0MB/s cp +0.9% BM_UFlat/7 12672 12391 862.1MB/s c +2.3% BM_UFlat/8 3507 3425 1040.9MB/s lsp +2.4% BM_UFlat/9 1004268 969395 1018.0MB/s xls +3.6% BM_UFlat/10 233 227 844.8MB/s xls_200 +2.6% BM_UFlat/11 230054 224981 647.8MB/s txt1 +2.3% BM_UFlat/12 201229 196447 610.5MB/s txt2 +2.4% BM_UFlat/13 609547 596761 685.3MB/s txt3 +2.1% BM_UFlat/14 824362 804821 573.8MB/s txt4 +2.4% BM_UFlat/15 371095 374899 1.3GB/s bin -1.0% BM_UFlat/16 267 267 717.8MB/s bin_200 +0.0% BM_UFlat/17 44623 43828 835.9MB/s sum +1.8% BM_UFlat/18 5077 4815 841.0MB/s man +5.4% BM_UFlat/19 74964 73210 1.5GB/s pb +2.4% BM_UFlat/20 237987 236745 746.0MB/s gaviota +0.5% Sum of all benchmarks 4794092 4697659 +2.1% Istanbul: Benchmark Base (ns) New (ns) Improvement ------------------------------------------------------------------------------------------------- BM_UFlat/0 98614 96376 1020.4MB/s html +2.3% BM_UFlat/1 963740 953241 707.2MB/s urls +1.1% BM_UFlat/2 25042 24769 4.8GB/s jpg +1.1% BM_UFlat/3 180 180 1065.6MB/s jpg_200 +0.0% BM_UFlat/4 45942 45403 1.9GB/s pdf +1.2% BM_UFlat/5 400135 390226 1008.2MB/s html4 +2.5% BM_UFlat/6 37768 37392 631.9MB/s cp +1.0% BM_UFlat/7 18585 18200 588.2MB/s c +2.1% BM_UFlat/8 5751 5690 627.7MB/s lsp +1.1% BM_UFlat/9 1543154 1542209 641.4MB/s xls +0.1% BM_UFlat/10 381 388 494.6MB/s xls_200 -1.8% BM_UFlat/11 339715 331973 440.1MB/s txt1 +2.3% BM_UFlat/12 294807 289418 415.4MB/s txt2 +1.9% BM_UFlat/13 906160 884094 463.3MB/s txt3 +2.5% BM_UFlat/14 1224221 1198435 386.1MB/s txt4 +2.2% BM_UFlat/15 516277 502923 979.5MB/s bin +2.7% BM_UFlat/16 405 402 477.2MB/s bin_200 +0.7% BM_UFlat/17 61640 60621 605.6MB/s sum +1.7% BM_UFlat/18 7326 7383 549.5MB/s man -0.8% BM_UFlat/19 94720 92653 1.2GB/s pb +2.2% BM_UFlat/20 360435 346687 510.6MB/s gaviota +4.0% Sum of all benchmarks 6944998 6828663 +1.7% git-svn-id: https://snappy.googlecode.com/svn/trunk@77 03e5f5b5-db94-4691-08a0-1a8bf15f6143 |
|
|
snappy.mirrorbot@gmail.com
|
328aafa198 |
Add support for uncompressing to iovecs (scatter I/O).
Windows does not have struct iovec defined anywhere, so we define our own version that's equal to what UNIX typically has. The bulk of this patch was contributed by Mohit Aron. R=jeff git-svn-id: https://snappy.googlecode.com/svn/trunk@76 03e5f5b5-db94-4691-08a0-1a8bf15f6143 |
|
|
snappy.mirrorbot@gmail.com
|
cd92eb0852 |
Some code reorganization needed for an internal change.
R=fikes git-svn-id: https://snappy.googlecode.com/svn/trunk@75 03e5f5b5-db94-4691-08a0-1a8bf15f6143 |
|
|
snappy.mirrorbot@gmail.com
|
698af469b4 |
Change a few ORs to additions where they don't matter. This helps the compiler
use the LEA instruction more efficiently, since e.g. a + (b << 2) can be encoded as one instruction. Even more importantly, it can constant-fold the COPY_* enums together with the shifted negative constants, which also saves some instructions. (We don't need it for LITERAL, since it happens to be 0.) I am unsure why the compiler couldn't do this itself, but the theory is that it cannot prove that len-1 and len-4 cannot underflow/wrap, and thus can't do the optimization safely. The gains are small but measurable; 0.5-1.0% over the BM_Z* benchmarks (measured on Westmere, Sandy Bridge and Istanbul). R=sanjay git-svn-id: https://snappy.googlecode.com/svn/trunk@69 03e5f5b5-db94-4691-08a0-1a8bf15f6143 |
|
|
snappy.mirrorbot@gmail.com
|
8b95464146 |
Snappy library no longer depends on iostream.
Achieved by moving logging macro definitions to a test-only header file, and by changing non-test code to use assert, fprintf, and abort instead of LOG/CHECK macros. R=sesse git-svn-id: https://snappy.googlecode.com/svn/trunk@62 03e5f5b5-db94-4691-08a0-1a8bf15f6143 |
|
|
snappy.mirrorbot@gmail.com
|
dc63e0ad96 |
For 32-bit platforms, do not try to accelerate multiple neighboring
32-bit loads with a 64-bit load during compression (it's not a win). The main target for this optimization is ARM, but 32-bit x86 gets a small gain, too, although there is noise in the microbenchmarks. It's a no-op for 64-bit x86. It does not affect decompression. Microbenchmark results on a Cortex-A9 1GHz, using g++ 4.6.2 (from Ubuntu/Linaro), -O2 -DNDEBUG -Wa,-march=armv7a -mtune=cortex-a9 -mthumb-interwork, minimum 1000 iterations: Benchmark Time(ns) CPU(ns) Iterations --------------------------------------------------- BM_ZFlat/0 1158277 1160000 1000 84.2MB/s html (23.57 %) [ +4.3%] BM_ZFlat/1 14861782 14860000 1000 45.1MB/s urls (50.89 %) [ +1.1%] BM_ZFlat/2 393595 390000 1000 310.5MB/s jpg (99.88 %) [ +0.0%] BM_ZFlat/3 650583 650000 1000 138.4MB/s pdf (82.13 %) [ +3.1%] BM_ZFlat/4 4661480 4660000 1000 83.8MB/s html4 (23.55 %) [ +4.3%] BM_ZFlat/5 491973 490000 1000 47.9MB/s cp (48.12 %) [ +2.0%] BM_ZFlat/6 193575 192678 1038 55.2MB/s c (42.40 %) [ +9.0%] BM_ZFlat/7 62343 62754 3187 56.5MB/s lsp (48.37 %) [ +2.6%] BM_ZFlat/8 17708468 17710000 1000 55.5MB/s xls (41.34 %) [ -0.3%] BM_ZFlat/9 3755345 3760000 1000 38.6MB/s txt1 (59.81 %) [ +8.2%] BM_ZFlat/10 3324217 3320000 1000 36.0MB/s txt2 (64.07 %) [ +4.2%] BM_ZFlat/11 10139932 10140000 1000 40.1MB/s txt3 (57.11 %) [ +6.4%] BM_ZFlat/12 13532109 13530000 1000 34.0MB/s txt4 (68.35 %) [ +5.0%] BM_ZFlat/13 4690847 4690000 1000 104.4MB/s bin (18.21 %) [ +4.1%] BM_ZFlat/14 830682 830000 1000 43.9MB/s sum (51.88 %) [ +1.2%] BM_ZFlat/15 84784 85011 2235 47.4MB/s man (59.36 %) [ +1.1%] BM_ZFlat/16 1293254 1290000 1000 87.7MB/s pb (23.15 %) [ +2.3%] BM_ZFlat/17 2775155 2780000 1000 63.2MB/s gaviota (38.27 %) [+12.2%] Core i7 in 32-bit mode (only one run and 100 iterations, though, so noisy): Benchmark Time(ns) CPU(ns) Iterations --------------------------------------------------- BM_ZFlat/0 227582 223464 3043 437.0MB/s html (23.57 %) [ +7.4%] BM_ZFlat/1 2982430 2918455 233 229.4MB/s urls (50.89 %) [ +2.9%] BM_ZFlat/2 46967 46658 15217 2.5GB/s jpg (99.88 %) [ +0.0%] BM_ZFlat/3 115298 114864 5833 783.2MB/s pdf (82.13 %) [ +1.5%] BM_ZFlat/4 913440 899743 778 434.2MB/s html4 (23.55 %) [ +0.3%] BM_ZFlat/5 110302 108571 7000 216.1MB/s cp (48.12 %) [ +0.0%] BM_ZFlat/6 44409 43372 15909 245.2MB/s c (42.40 %) [ +0.8%] BM_ZFlat/7 15713 15643 46667 226.9MB/s lsp (48.37 %) [ +2.7%] BM_ZFlat/8 2625539 2602230 269 377.4MB/s xls (41.34 %) [ +1.4%] BM_ZFlat/9 808884 811429 875 178.8MB/s txt1 (59.81 %) [ -3.9%] BM_ZFlat/10 709532 700000 1000 170.5MB/s txt2 (64.07 %) [ +0.0%] BM_ZFlat/11 2177682 2162162 333 188.2MB/s txt3 (57.11 %) [ -1.4%] BM_ZFlat/12 2849640 2840000 250 161.8MB/s txt4 (68.35 %) [ -1.4%] BM_ZFlat/13 849760 835476 778 585.8MB/s bin (18.21 %) [ +1.2%] BM_ZFlat/14 165940 164571 4375 221.6MB/s sum (51.88 %) [ +1.4%] BM_ZFlat/15 20939 20571 35000 196.0MB/s man (59.36 %) [ +2.1%] BM_ZFlat/16 239209 236544 2917 478.1MB/s pb (23.15 %) [ +4.2%] BM_ZFlat/17 616206 610000 1000 288.2MB/s gaviota (38.27 %) [ -1.6%] R=sanjay git-svn-id: https://snappy.googlecode.com/svn/trunk@60 03e5f5b5-db94-4691-08a0-1a8bf15f6143 |
|
|
snappy.mirrorbot@gmail.com
|
f8829ea39d |
Enable the use of unaligned loads and stores for ARM-based architectures
where they are available (ARMv7 and higher). This gives a significant speed boost on ARM, both for compression and decompression. It should not affect x86 at all. There are more changes possible to speed up ARM, but it might not be that easy to do without hurting x86 or making the code uglier. Also, we de not try to use NEON yet. Microbenchmark results on a Cortex-A9 1GHz, using g++ 4.6.2 (from Ubuntu/Linaro), -O2 -DNDEBUG -Wa,-march=armv7a -mtune=cortex-a9 -mthumb-interwork: Benchmark Time(ns) CPU(ns) Iterations --------------------------------------------------- BM_UFlat/0 524806 529100 378 184.6MB/s html [+33.6%] BM_UFlat/1 5139790 5200000 100 128.8MB/s urls [+28.8%] BM_UFlat/2 86540 84166 1901 1.4GB/s jpg [ +0.6%] BM_UFlat/3 215351 210176 904 428.0MB/s pdf [+29.8%] BM_UFlat/4 2144490 2100000 100 186.0MB/s html4 [+33.3%] BM_UFlat/5 194482 190000 1000 123.5MB/s cp [+36.2%] BM_UFlat/6 91843 90175 2107 117.9MB/s c [+38.6%] BM_UFlat/7 28535 28426 6684 124.8MB/s lsp [+34.7%] BM_UFlat/8 9206600 9200000 100 106.7MB/s xls [+42.4%] BM_UFlat/9 1865273 1886792 106 76.9MB/s txt1 [+32.5%] BM_UFlat/10 1576809 1587301 126 75.2MB/s txt2 [+32.3%] BM_UFlat/11 4968450 4900000 100 83.1MB/s txt3 [+32.7%] BM_UFlat/12 6673970 6700000 100 68.6MB/s txt4 [+32.8%] BM_UFlat/13 2391470 2400000 100 203.9MB/s bin [+29.2%] BM_UFlat/14 334601 344827 522 105.8MB/s sum [+30.6%] BM_UFlat/15 37404 38080 5252 105.9MB/s man [+33.8%] BM_UFlat/16 535470 540540 370 209.2MB/s pb [+31.2%] BM_UFlat/17 1875245 1886792 106 93.2MB/s gaviota [+37.8%] BM_UValidate/0 178425 179533 1114 543.9MB/s html [ +2.7%] BM_UValidate/1 2100450 2000000 100 334.8MB/s urls [ +5.0%] BM_UValidate/2 1039 1044 172413 113.3GB/s jpg [ +3.4%] BM_UValidate/3 59423 59470 3363 1.5GB/s pdf [ +7.8%] BM_UValidate/4 760716 766283 261 509.8MB/s html4 [ +6.5%] BM_ZFlat/0 1204632 1204819 166 81.1MB/s html (23.57 %) [+32.8%] BM_ZFlat/1 15656190 15600000 100 42.9MB/s urls (50.89 %) [+27.6%] BM_ZFlat/2 403336 410677 487 294.8MB/s jpg (99.88 %) [+16.5%] BM_ZFlat/3 664073 671140 298 134.0MB/s pdf (82.13 %) [+28.4%] BM_ZFlat/4 4961940 4900000 100 79.7MB/s html4 (23.55 %) [+30.6%] BM_ZFlat/5 500664 501253 399 46.8MB/s cp (48.12 %) [+33.4%] BM_ZFlat/6 217276 215982 926 49.2MB/s c (42.40 %) [+25.0%] BM_ZFlat/7 64122 65487 3054 54.2MB/s lsp (48.37 %) [+36.1%] BM_ZFlat/8 18045730 18000000 100 54.6MB/s xls (41.34 %) [+34.4%] BM_ZFlat/9 4051530 4000000 100 36.3MB/s txt1 (59.81 %) [+25.0%] BM_ZFlat/10 3451800 3500000 100 34.1MB/s txt2 (64.07 %) [+25.7%] BM_ZFlat/11 11052340 11100000 100 36.7MB/s txt3 (57.11 %) [+24.3%] BM_ZFlat/12 14538690 14600000 100 31.5MB/s txt4 (68.35 %) [+24.7%] BM_ZFlat/13 5041850 5000000 100 97.9MB/s bin (18.21 %) [+32.0%] BM_ZFlat/14 908840 909090 220 40.1MB/s sum (51.88 %) [+22.2%] BM_ZFlat/15 86921 86206 1972 46.8MB/s man (59.36 %) [+42.2%] BM_ZFlat/16 1312315 1315789 152 86.0MB/s pb (23.15 %) [+34.5%] BM_ZFlat/17 3173120 3200000 100 54.9MB/s gaviota (38.27%) [+28.1%] The move from 64-bit to 32-bit operations for the copies also affected 32-bit x86; positive on the decompression side, and slightly negative on the compression side (unless that is noise; I only ran once): Benchmark Time(ns) CPU(ns) Iterations ----------------------------------------------------- BM_UFlat/0 86279 86140 7778 1.1GB/s html [ +7.5%] BM_UFlat/1 839265 822622 778 813.9MB/s urls [ +9.4%] BM_UFlat/2 9180 9143 87500 12.9GB/s jpg [ +1.2%] BM_UFlat/3 35080 35000 20000 2.5GB/s pdf [+10.1%] BM_UFlat/4 350318 345000 2000 1.1GB/s html4 [ +7.0%] BM_UFlat/5 33808 33472 21212 701.0MB/s cp [ +9.0%] BM_UFlat/6 15201 15214 46667 698.9MB/s c [+14.9%] BM_UFlat/7 4652 4651 159091 762.9MB/s lsp [ +7.5%] BM_UFlat/8 1285551 1282528 538 765.7MB/s xls [+10.7%] BM_UFlat/9 282510 281690 2414 514.9MB/s txt1 [+13.6%] BM_UFlat/10 243494 239286 2800 498.9MB/s txt2 [+14.4%] BM_UFlat/11 743625 740000 1000 550.0MB/s txt3 [+14.3%] BM_UFlat/12 999441 989717 778 464.3MB/s txt4 [+16.1%] BM_UFlat/13 412402 410076 1707 1.2GB/s bin [ +7.3%] BM_UFlat/14 54876 54000 10000 675.3MB/s sum [+13.0%] BM_UFlat/15 6146 6100 100000 660.8MB/s man [+14.8%] BM_UFlat/16 90496 90286 8750 1.2GB/s pb [ +4.0%] BM_UFlat/17 292650 292000 2500 602.0MB/s gaviota [+18.1%] BM_UValidate/0 49620 49699 14286 1.9GB/s html [ +0.0%] BM_UValidate/1 501371 500000 1000 1.3GB/s urls [ +0.0%] BM_UValidate/2 232 227 3043478 521.5GB/s jpg [ +1.3%] BM_UValidate/3 17250 17143 43750 5.1GB/s pdf [ -1.3%] BM_UValidate/4 198643 200000 3500 1.9GB/s html4 [ -0.9%] BM_ZFlat/0 227128 229415 3182 425.7MB/s html (23.57 %) [ -1.4%] BM_ZFlat/1 2970089 2960000 250 226.2MB/s urls (50.89 %) [ -1.9%] BM_ZFlat/2 45683 44999 15556 2.6GB/s jpg (99.88 %) [ +2.2%] BM_ZFlat/3 114661 113136 6364 795.1MB/s pdf (82.13 %) [ -1.5%] BM_ZFlat/4 919702 914286 875 427.2MB/s html4 (23.55%) [ -1.3%] BM_ZFlat/5 108189 108422 6364 216.4MB/s cp (48.12 %) [ -1.2%] BM_ZFlat/6 44525 44000 15909 241.7MB/s c (42.40 %) [ -2.9%] BM_ZFlat/7 15973 15857 46667 223.8MB/s lsp (48.37 %) [ +0.0%] BM_ZFlat/8 2677888 2639405 269 372.1MB/s xls (41.34 %) [ -1.4%] BM_ZFlat/9 800715 780000 1000 186.0MB/s txt1 (59.81 %) [ -0.4%] BM_ZFlat/10 700089 700000 1000 170.5MB/s txt2 (64.07 %) [ -2.9%] BM_ZFlat/11 2159356 2138365 318 190.3MB/s txt3 (57.11 %) [ -0.3%] BM_ZFlat/12 2796143 2779923 259 165.3MB/s txt4 (68.35 %) [ -1.4%] BM_ZFlat/13 856458 835476 778 585.8MB/s bin (18.21 %) [ -0.1%] BM_ZFlat/14 166908 166857 4375 218.6MB/s sum (51.88 %) [ -1.4%] BM_ZFlat/15 21181 20857 35000 193.3MB/s man (59.36 %) [ -0.8%] BM_ZFlat/16 244009 239973 2917 471.3MB/s pb (23.15 %) [ -1.4%] BM_ZFlat/17 596362 590000 1000 297.9MB/s gaviota (38.27%) [ +0.0%] R=sanjay git-svn-id: https://snappy.googlecode.com/svn/trunk@59 03e5f5b5-db94-4691-08a0-1a8bf15f6143 |
|
|
snappy.mirrorbot@gmail.com
|
e750dc0f05 |
Minor refactoring to accomodate changes in Google's internal code tree.
git-svn-id: https://snappy.googlecode.com/svn/trunk@57 03e5f5b5-db94-4691-08a0-1a8bf15f6143 |
|
|
snappy.mirrorbot@gmail.com
|
d9068ee301 |
Fix public issue r57: Fix most warnings with -Wall, mostly signed/unsigned
warnings. There are still some in the unit test, but the main .cc file should be clean. We haven't enabled -Wall for the default build, since the unit test is still not clean. This also fixes a real bug in the open-source implementation of ReadFileToStringOrDie(); it would not detect errors correctly. I had to go through some pains to avoid performance loss as the types were changed; I think there might still be some with 32-bit if and only if LFS is enabled (ie., size_t is 64-bit), but for regular 32-bit and 64-bit I can't see any losses, and I've diffed the generated GCC assembler between the old and new code without seeing any significant choices. If anything, it's ever so slightly faster. This may or may not enable compression of very large blocks (>2^32 bytes) when size_t is 64-bit, but I haven't checked, and it is still not a supported case. git-svn-id: https://snappy.googlecode.com/svn/trunk@56 03e5f5b5-db94-4691-08a0-1a8bf15f6143 |
|
|
snappy.mirrorbot@gmail.com
|
d7eb2dc413 |
Speed up decompression by moving the refill check to the end of the loop.
This seems to work because in most of the branches, the compiler can evaluate “ip_limit_ - ip” in a more efficient way than reloading ip_limit_ from memory (either by already having the entire expression in a register, or reconstructing it from “avail”, or something else). Memory loads, even from L1, are seemingly costly in the big picture at the current decompression speeds. Microbenchmarks (64-bit, opt mode): Westmere (Intel Core i7): Benchmark Time(ns) CPU(ns) Iterations -------------------------------------------- BM_UFlat/0 74492 74491 187894 1.3GB/s html [ +5.9%] BM_UFlat/1 712268 712263 19644 940.0MB/s urls [ +3.8%] BM_UFlat/2 10591 10590 1000000 11.2GB/s jpg [ -6.8%] BM_UFlat/3 29643 29643 469915 3.0GB/s pdf [ +7.9%] BM_UFlat/4 304669 304667 45930 1.3GB/s html4 [ +4.8%] BM_UFlat/5 28508 28507 490077 823.1MB/s cp [ +4.0%] BM_UFlat/6 12415 12415 1000000 856.5MB/s c [ +8.6%] BM_UFlat/7 3415 3415 4084723 1039.0MB/s lsp [+18.0%] BM_UFlat/8 979569 979563 14261 1002.5MB/s xls [ +5.8%] BM_UFlat/9 230150 230148 60934 630.2MB/s txt1 [ +5.2%] BM_UFlat/10 197167 197166 71135 605.5MB/s txt2 [ +4.7%] BM_UFlat/11 607394 607390 23041 670.1MB/s txt3 [ +5.6%] BM_UFlat/12 808502 808496 17316 568.4MB/s txt4 [ +5.0%] BM_UFlat/13 372791 372788 37564 1.3GB/s bin [ +3.3%] BM_UFlat/14 44541 44541 313969 818.8MB/s sum [ +5.7%] BM_UFlat/15 4833 4833 2898697 834.1MB/s man [ +4.8%] BM_UFlat/16 79855 79855 175356 1.4GB/s pb [ +4.8%] BM_UFlat/17 245845 245843 56838 715.0MB/s gaviota [ +5.8%] Clovertown (Intel Core 2): Benchmark Time(ns) CPU(ns) Iterations -------------------------------------------- BM_UFlat/0 107911 107890 100000 905.1MB/s html [ +2.2%] BM_UFlat/1 1011237 1011041 10000 662.3MB/s urls [ +2.5%] BM_UFlat/2 26775 26770 523089 4.4GB/s jpg [ +0.0%] BM_UFlat/3 48103 48095 290618 1.8GB/s pdf [ +3.4%] BM_UFlat/4 437724 437644 31937 892.6MB/s html4 [ +2.1%] BM_UFlat/5 39607 39600 358284 592.5MB/s cp [ +2.4%] BM_UFlat/6 18227 18224 768191 583.5MB/s c [ +2.7%] BM_UFlat/7 5171 5170 2709437 686.4MB/s lsp [ +3.9%] BM_UFlat/8 1560291 1559989 8970 629.5MB/s xls [ +3.6%] BM_UFlat/9 335401 335343 41731 432.5MB/s txt1 [ +3.0%] BM_UFlat/10 287014 286963 48758 416.0MB/s txt2 [ +2.8%] BM_UFlat/11 888522 888356 15752 458.1MB/s txt3 [ +2.9%] BM_UFlat/12 1186600 1186378 10000 387.3MB/s txt4 [ +3.1%] BM_UFlat/13 572295 572188 24468 855.4MB/s bin [ +2.1%] BM_UFlat/14 64060 64049 218401 569.4MB/s sum [ +4.1%] BM_UFlat/15 7264 7263 1916168 555.0MB/s man [ +1.4%] BM_UFlat/16 108853 108836 100000 1039.1MB/s pb [ +1.7%] BM_UFlat/17 364289 364223 38419 482.6MB/s gaviota [ +4.9%] Barcelona (AMD Opteron): Benchmark Time(ns) CPU(ns) Iterations -------------------------------------------- BM_UFlat/0 103900 103871 100000 940.2MB/s html [ +8.3%] BM_UFlat/1 1000435 1000107 10000 669.5MB/s urls [ +6.6%] BM_UFlat/2 24659 24652 567362 4.8GB/s jpg [ +0.1%] BM_UFlat/3 48206 48193 291121 1.8GB/s pdf [ +5.0%] BM_UFlat/4 421980 421850 33174 926.0MB/s html4 [ +7.3%] BM_UFlat/5 40368 40357 346994 581.4MB/s cp [ +8.7%] BM_UFlat/6 19836 19830 708695 536.2MB/s c [ +8.0%] BM_UFlat/7 6100 6098 2292774 581.9MB/s lsp [ +9.0%] BM_UFlat/8 1693093 1692514 8261 580.2MB/s xls [ +8.0%] BM_UFlat/9 365991 365886 38225 396.4MB/s txt1 [ +7.1%] BM_UFlat/10 311330 311238 44950 383.6MB/s txt2 [ +7.6%] BM_UFlat/11 975037 974737 14376 417.5MB/s txt3 [ +6.9%] BM_UFlat/12 1303558 1303175 10000 352.6MB/s txt4 [ +7.3%] BM_UFlat/13 517448 517290 27144 946.2MB/s bin [ +5.5%] BM_UFlat/14 66537 66518 210352 548.3MB/s sum [ +7.5%] BM_UFlat/15 7976 7974 1760383 505.6MB/s man [ +5.6%] BM_UFlat/16 103121 103092 100000 1097.0MB/s pb [ +8.7%] BM_UFlat/17 391431 391314 35733 449.2MB/s gaviota [ +6.5%] R=sanjay git-svn-id: https://snappy.googlecode.com/svn/trunk@54 03e5f5b5-db94-4691-08a0-1a8bf15f6143 |
|
|
snappy.mirrorbot@gmail.com
|
5ed51ce15f |
Speed up decompression by making the fast path for literals faster.
We do the fast-path step as soon as possible; in fact, as soon as we know the literal length. Since we usually hit the fast path, we can then skip the checks for long literals and available input space (beyond what the fast path check already does). Note that this changes the decompression Writer API; however, it does not change the ABI, since writers are always templatized and as such never cross compilation units. The new API is slightly more general, in that it doesn't hard-code the value 16. Note that we also take care to check for len <= 16 first, since the other two checks almost always succeed (so we don't want to waste time checking for them until we have to). The improvements are most marked on Nehalem, but are generally positive on other platforms as well. All microbenchmarks are 64-bit, opt. Clovertown (Core 2): Benchmark Time(ns) CPU(ns) Iterations -------------------------------------------- BM_UFlat/0 110226 110224 100000 886.0MB/s html [ +1.5%] BM_UFlat/1 1036523 1036508 10000 646.0MB/s urls [ -0.8%] BM_UFlat/2 26775 26775 522570 4.4GB/s jpg [ +0.0%] BM_UFlat/3 49738 49737 280974 1.8GB/s pdf [ +0.3%] BM_UFlat/4 446790 446792 31334 874.3MB/s html4 [ +0.8%] BM_UFlat/5 40561 40562 350424 578.5MB/s cp [ +1.3%] BM_UFlat/6 18722 18722 746903 568.0MB/s c [ +1.4%] BM_UFlat/7 5373 5373 2608632 660.5MB/s lsp [ +8.3%] BM_UFlat/8 1615716 1615718 8670 607.8MB/s xls [ +2.0%] BM_UFlat/9 345278 345281 40481 420.1MB/s txt1 [ +1.4%] BM_UFlat/10 294855 294855 47452 404.9MB/s txt2 [ +1.6%] BM_UFlat/11 914263 914263 15316 445.2MB/s txt3 [ +1.1%] BM_UFlat/12 1222694 1222691 10000 375.8MB/s txt4 [ +1.4%] BM_UFlat/13 584495 584489 23954 837.4MB/s bin [ -0.6%] BM_UFlat/14 66662 66662 210123 547.1MB/s sum [ +1.2%] BM_UFlat/15 7368 7368 1881856 547.1MB/s man [ +4.0%] BM_UFlat/16 110727 110726 100000 1021.4MB/s pb [ +2.3%] BM_UFlat/17 382138 382141 36616 460.0MB/s gaviota [ -0.7%] Westmere (Core i7): Benchmark Time(ns) CPU(ns) Iterations -------------------------------------------- BM_UFlat/0 78861 78853 177703 1.2GB/s html [ +2.1%] BM_UFlat/1 739560 739491 18912 905.4MB/s urls [ +3.4%] BM_UFlat/2 9867 9866 1419014 12.0GB/s jpg [ +3.4%] BM_UFlat/3 31989 31986 438385 2.7GB/s pdf [ +0.2%] BM_UFlat/4 319406 319380 43771 1.2GB/s html4 [ +1.9%] BM_UFlat/5 29639 29636 472862 791.7MB/s cp [ +5.2%] BM_UFlat/6 13478 13477 1000000 789.0MB/s c [ +2.3%] BM_UFlat/7 4030 4029 3475364 880.7MB/s lsp [ +8.7%] BM_UFlat/8 1036585 1036492 10000 947.5MB/s xls [ +6.9%] BM_UFlat/9 242127 242105 57838 599.1MB/s txt1 [ +3.0%] BM_UFlat/10 206499 206480 67595 578.2MB/s txt2 [ +3.4%] BM_UFlat/11 641635 641570 21811 634.4MB/s txt3 [ +2.4%] BM_UFlat/12 848847 848769 16443 541.4MB/s txt4 [ +3.1%] BM_UFlat/13 384968 384938 36366 1.2GB/s bin [ +0.3%] BM_UFlat/14 47106 47101 297770 774.3MB/s sum [ +4.4%] BM_UFlat/15 5063 5063 2772202 796.2MB/s man [ +7.7%] BM_UFlat/16 83663 83656 167697 1.3GB/s pb [ +1.8%] BM_UFlat/17 260224 260198 53823 675.6MB/s gaviota [ -0.5%] Barcelona (Opteron): Benchmark Time(ns) CPU(ns) Iterations -------------------------------------------- BM_UFlat/0 112490 112457 100000 868.4MB/s html [ -0.4%] BM_UFlat/1 1066719 1066339 10000 627.9MB/s urls [ +1.0%] BM_UFlat/2 24679 24672 563802 4.8GB/s jpg [ +0.7%] BM_UFlat/3 50603 50589 277285 1.7GB/s pdf [ +2.6%] BM_UFlat/4 452982 452849 30900 862.6MB/s html4 [ -0.2%] BM_UFlat/5 43860 43848 319554 535.1MB/s cp [ +1.2%] BM_UFlat/6 21419 21413 653573 496.6MB/s c [ +1.0%] BM_UFlat/7 6646 6645 2105405 534.1MB/s lsp [ +0.3%] BM_UFlat/8 1828487 1827886 7658 537.3MB/s xls [ +2.6%] BM_UFlat/9 391824 391714 35708 370.3MB/s txt1 [ +2.2%] BM_UFlat/10 334913 334816 41885 356.6MB/s txt2 [ +1.7%] BM_UFlat/11 1042062 1041674 10000 390.7MB/s txt3 [ +1.1%] BM_UFlat/12 1398902 1398456 10000 328.6MB/s txt4 [ +1.7%] BM_UFlat/13 545706 545530 25669 897.2MB/s bin [ -0.4%] BM_UFlat/14 71512 71505 196035 510.0MB/s sum [ +1.4%] BM_UFlat/15 8422 8421 1665036 478.7MB/s man [ +2.6%] BM_UFlat/16 112053 112048 100000 1009.3MB/s pb [ -0.4%] BM_UFlat/17 416723 416713 33612 421.8MB/s gaviota [ -2.0%] R=sanjay git-svn-id: https://snappy.googlecode.com/svn/trunk@53 03e5f5b5-db94-4691-08a0-1a8bf15f6143 |
|
|
snappy.mirrorbot@gmail.com
|
57e7cd7255 |
Fix public issue #44: Make the definition and declaration of CompressFragment
identical, even regarding cv-qualifiers. This is required to work around a bug in the Solaris Studio C++ compiler (it does not properly disregard cv-qualifiers when doing name mangling). R=sanjay git-svn-id: https://snappy.googlecode.com/svn/trunk@44 03e5f5b5-db94-4691-08a0-1a8bf15f6143 |
|
|
snappy.mirrorbot@gmail.com
|
f540673740 |
Speed up decompression by removing a fast-path attempt.
Whenever we try to enter a copy fast-path, there is a certain cost in checking that all the preconditions are in place, but it's normally offset by the fact that we can usually take the cheaper path. However, in a certain path we've already established that "avail < literal_length", which usually means that either the available space is small, or the literal is big. Both will disqualify us from taking the fast path, and thus we take the hit from the precondition checking without gaining much from having a fast path. Thus, simply don't try the fast path in this situation -- we're already on a slow path anyway (one where we need to refill more data from the reader). I'm a bit surprised at how much this gained; it could be that this path is more common than I thought, or that the simpler structure somehow makes the compiler happier. I haven't looked at the assembler, but it's a win across the board on both Core 2, Core i7 and Opteron, at least for the cases we typically care about. The gains seem to be the largest on Core i7, though. Results from my Core i7 workstation: Benchmark Time(ns) CPU(ns) Iterations --------------------------------------------------- BM_UFlat/0 73337 73091 190996 1.3GB/s html [ +1.7%] BM_UFlat/1 696379 693501 20173 965.5MB/s urls [ +2.7%] BM_UFlat/2 9765 9734 1472135 12.1GB/s jpg [ +0.7%] BM_UFlat/3 29720 29621 472973 3.0GB/s pdf [ +1.8%] BM_UFlat/4 294636 293834 47782 1.3GB/s html4 [ +2.3%] BM_UFlat/5 28399 28320 494700 828.5MB/s cp [ +3.5%] BM_UFlat/6 12795 12760 1000000 833.3MB/s c [ +1.2%] BM_UFlat/7 3984 3973 3526448 893.2MB/s lsp [ +5.7%] BM_UFlat/8 991996 989322 14141 992.6MB/s xls [ +3.3%] BM_UFlat/9 228620 227835 61404 636.6MB/s txt1 [ +4.0%] BM_UFlat/10 197114 196494 72165 607.5MB/s txt2 [ +3.5%] BM_UFlat/11 605240 603437 23217 674.4MB/s txt3 [ +3.7%] BM_UFlat/12 804157 802016 17456 573.0MB/s txt4 [ +3.9%] BM_UFlat/13 347860 346998 40346 1.4GB/s bin [ +1.2%] BM_UFlat/14 44684 44559 315315 818.4MB/s sum [ +2.3%] BM_UFlat/15 5120 5106 2739726 789.4MB/s man [ +3.3%] BM_UFlat/16 76591 76355 183486 1.4GB/s pb [ +2.8%] BM_UFlat/17 238564 237828 58824 739.1MB/s gaviota [ +1.6%] BM_UValidate/0 42194 42060 333333 2.3GB/s html [ -0.1%] BM_UValidate/1 433182 432005 32407 1.5GB/s urls [ -0.1%] BM_UValidate/2 197 196 71428571 603.3GB/s jpg [ +0.5%] BM_UValidate/3 14494 14462 972222 6.1GB/s pdf [ +0.5%] BM_UValidate/4 168444 167836 83832 2.3GB/s html4 [ +0.1%] R=jeff Revision created by MOE tool push_codebase. git-svn-id: https://snappy.googlecode.com/svn/trunk@42 03e5f5b5-db94-4691-08a0-1a8bf15f6143 |
|
|
snappy.mirrorbot@gmail.com
|
197f3ee9f9 |
Speed up decompression by not needing a lookup table for literal items.
Looking up into and decoding the values from char_table has long shown up as a hotspot in the decompressor. While it turns out that it's hard to make a more efficient decoder for the copy ops, the literals are simple enough that we can decode them without needing a table lookup. (This means that 1/4 of the table is now unused, although that in itself doesn't buy us anything.) The gains are small, but definitely present; some tests win as much as 10%, but 1-4% is more typical. These results are from Core i7, in 64-bit mode; Core 2 and Opteron show similar results. (I've run with more iterations than unusual to make sure the smaller gains don't drown entirely in noise.) Benchmark Time(ns) CPU(ns) Iterations --------------------------------------------------- BM_UFlat/0 74665 74428 182055 1.3GB/s html [ +3.1%] BM_UFlat/1 714106 711997 19663 940.4MB/s urls [ +4.4%] BM_UFlat/2 9820 9789 1427115 12.1GB/s jpg [ -1.2%] BM_UFlat/3 30461 30380 465116 2.9GB/s pdf [ +0.8%] BM_UFlat/4 301445 300568 46512 1.3GB/s html4 [ +2.2%] BM_UFlat/5 29338 29263 479452 801.8MB/s cp [ +1.6%] BM_UFlat/6 13004 12970 1000000 819.9MB/s c [ +2.1%] BM_UFlat/7 4180 4168 3349282 851.4MB/s lsp [ +1.3%] BM_UFlat/8 1026149 1024000 10000 959.0MB/s xls [+10.7%] BM_UFlat/9 237441 236830 59072 612.4MB/s txt1 [ +0.3%] BM_UFlat/10 203966 203298 69307 587.2MB/s txt2 [ +0.8%] BM_UFlat/11 627230 625000 22400 651.2MB/s txt3 [ +0.7%] BM_UFlat/12 836188 833979 16787 551.0MB/s txt4 [ +1.3%] BM_UFlat/13 351904 350750 39886 1.4GB/s bin [ +3.8%] BM_UFlat/14 45685 45562 308370 800.4MB/s sum [ +5.9%] BM_UFlat/15 5286 5270 2656546 764.9MB/s man [ +1.5%] BM_UFlat/16 78774 78544 178117 1.4GB/s pb [ +4.3%] BM_UFlat/17 242270 241345 58091 728.3MB/s gaviota [ +1.2%] BM_UValidate/0 42149 42000 333333 2.3GB/s html [ -3.0%] BM_UValidate/1 432741 431303 32483 1.5GB/s urls [ +7.8%] BM_UValidate/2 198 197 71428571 600.7GB/s jpg [+16.8%] BM_UValidate/3 14560 14521 965517 6.1GB/s pdf [ -4.1%] BM_UValidate/4 169065 168671 83832 2.3GB/s html4 [ -2.9%] R=jeff Revision created by MOE tool push_codebase. git-svn-id: https://snappy.googlecode.com/svn/trunk@41 03e5f5b5-db94-4691-08a0-1a8bf15f6143 |
|
|
snappy.mirrorbot@gmail.com
|
2e12124bd8 |
Remove an unneeded goto in the decompressor; it turns out that the
state of ip_ after decompression (or attempted decompresion) is completely irrelevant, so we don't need the trailer. Performance is, as expected, mostly flat -- there's a curious ~3-5% loss in the "lsp" test, but that test case is so short it is hard to say anything definitive about why (most likely, it's some sort of unrelated effect). R=jeff git-svn-id: https://snappy.googlecode.com/svn/trunk@39 03e5f5b5-db94-4691-08a0-1a8bf15f6143 |
|
|
snappy.mirrorbot@gmail.com
|
c266bbf321 |
Speed up decompression by caching ip_.
It is seemingly hard for the compiler to understand that ip_, the current input pointer into the compressed data stream, can not alias on anything else, and thus using it directly will incur memory traffic as it cannot be kept in a register. The code already knew about this and cached it into a local variable, but since Step() only decoded one tag, it had to move ip_ back into place between every tag. This seems to have cost us a significant amount of performance, so changing Step() into a function that decodes as much as it can before it saves ip_ back and returns. (Note that Step() was already inlined, so it is not the manual inlining that buys the performance here.) The wins are about 3-6% for Core 2, 6-13% on Core i7 and 5-12% on Opteron (for plain array-to-array decompression, in 64-bit opt mode). There is a tiny difference in the behavior here; if an invalid literal is encountered (ie., the writer refuses the Append() operation), ip_ will now point to the byte past the tag byte, instead of where the literal was originally thought to end. However, we don't use ip_ for anything after DecompressAllTags() has returned, so this should not change external behavior in any way. Microbenchmark results for Core i7, 64-bit (Opteron results are similar): Benchmark Time(ns) CPU(ns) Iterations --------------------------------------------------- BM_UFlat/0 79134 79110 8835 1.2GB/s html [ +6.2%] BM_UFlat/1 786126 786096 891 851.8MB/s urls [+10.0%] BM_UFlat/2 9948 9948 69125 11.9GB/s jpg [ -1.3%] BM_UFlat/3 31999 31998 21898 2.7GB/s pdf [ +6.5%] BM_UFlat/4 318909 318829 2204 1.2GB/s html4 [ +6.5%] BM_UFlat/5 31384 31390 22363 747.5MB/s cp [ +9.2%] BM_UFlat/6 14037 14034 49858 757.7MB/s c [+10.6%] BM_UFlat/7 4612 4612 151395 769.5MB/s lsp [ +9.5%] BM_UFlat/8 1203174 1203007 582 816.3MB/s xls [+19.3%] BM_UFlat/9 253869 253955 2757 571.1MB/s txt1 [+11.4%] BM_UFlat/10 219292 219290 3194 544.4MB/s txt2 [+12.1%] BM_UFlat/11 672135 672131 1000 605.5MB/s txt3 [+11.2%] BM_UFlat/12 902512 902492 776 509.2MB/s txt4 [+12.5%] BM_UFlat/13 372110 371998 1881 1.3GB/s bin [ +5.8%] BM_UFlat/14 50407 50407 10000 723.5MB/s sum [+13.5%] BM_UFlat/15 5699 5701 100000 707.2MB/s man [+12.4%] BM_UFlat/16 83448 83424 8383 1.3GB/s pb [ +5.7%] BM_UFlat/17 256958 256963 2723 684.1MB/s gaviota [ +7.9%] BM_UValidate/0 42795 42796 16351 2.2GB/s html [+25.8%] BM_UValidate/1 490672 490622 1427 1.3GB/s urls [+22.7%] BM_UValidate/2 237 237 2950297 499.0GB/s jpg [+24.9%] BM_UValidate/3 14610 14611 47901 6.0GB/s pdf [+26.8%] BM_UValidate/4 171973 171990 4071 2.2GB/s html4 [+25.7%] git-svn-id: https://snappy.googlecode.com/svn/trunk@38 03e5f5b5-db94-4691-08a0-1a8bf15f6143 |
|
|
snappy.mirrorbot@gmail.com
|
7e8ca8f831 |
Change on 2011-03-25 19:18:00-07:00 by sesse
Replace the Apache 2.0 license header by the BSD-type license header; somehow a lot of the files were missed in the last round. R=dannyb,csilvers DELTA=147 (74 added, 2 deleted, 71 changed) Change on 2011-03-25 19:25:07-07:00 by sesse Unbreak the build; the relicensing removed a bit too much (only comments were intended, but I also accidentially removed some of the top lines of the actual source). Revision created by MOE tool push_codebase. MOE_MIGRATION=1072 git-svn-id: https://snappy.googlecode.com/svn/trunk@21 03e5f5b5-db94-4691-08a0-1a8bf15f6143 |
|
|
snappy.mirrorbot@gmail.com
|
28a6440239 |
Revision created by MOE tool push_codebase.
MOE_MIGRATION= git-svn-id: https://snappy.googlecode.com/svn/trunk@2 03e5f5b5-db94-4691-08a0-1a8bf15f6143 |