5ed51ce15fc4ff8d2f7235704eb6b0c3f762fb88
8 Commits
| Author | SHA1 | Message | Date | |
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snappy.mirrorbot@gmail.com
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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 |
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snappy.mirrorbot@gmail.com
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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 |
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snappy.mirrorbot@gmail.com
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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 |
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snappy.mirrorbot@gmail.com
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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 |
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snappy.mirrorbot@gmail.com
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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 |
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snappy.mirrorbot@gmail.com
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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 |
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snappy.mirrorbot@gmail.com
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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 |
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snappy.mirrorbot@gmail.com
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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 |