1e00b50953
When searching for a small array in a large array, scanning ahead is productive. The switch from counting indexes to reslicing the slice appears to improve performance in this case. The fairly arbitrary value `na << 2` is like `nb / 4 > na` except that it computes faster, and lets us avoid the expensive overhead unless we have reason to expect that there's significantly more items in b than in a. Improvements: Not huge in some cases, but sometimes quite noticeable, especially as the frequency of overlap increases, which is also the expensive case in other ways. name old time/op new time/op delta ImportMutexSampleData/64K/2Kr/40/none/write-0-8 501ms ± 4% 486ms ± 2% ~ (p=0.052 n=6+5) ImportMutexSampleData/64K/2Kr/40/none/write-1-8 756ms ± 5% 698ms ± 5% -7.62% (p=0.002 n=6+6) ImportMutexSampleData/64K/2Kr/80/none/write-0-8 292ms ± 3% 276ms ± 4% -5.46% (p=0.002 n=6+6) ImportMutexSampleData/64K/2Kr/80/none/write-1-8 511ms ± 6% 482ms ± 4% -5.72% (p=0.015 n=6+6) ImportMutexSampleData/64K/2Kr/240/none/write-0-8 153ms ± 3% 132ms ± 5% -13.91% (p=0.008 n=5+5) ImportMutexSampleData/64K/2Kr/240/none/write-1-8 354ms ± 2% 215ms ± 6% -39.41% (p=0.004 n=5+6) ImportMutexSampleData/1K/2Kr/40/none/write-0-8 565ms ± 3% 543ms ± 3% -3.89% (p=0.015 n=6+6) ImportMutexSampleData/1K/2Kr/40/none/write-1-8 807ms ± 6% 778ms ± 3% ~ (p=0.180 n=6+6) ImportMutexSampleData/1K/2Kr/80/none/write-0-8 317ms ± 3% 300ms ± 1% -5.40% (p=0.002 n=6+6) ImportMutexSampleData/1K/2Kr/80/none/write-1-8 462ms ± 3% 437ms ± 4% -5.31% (p=0.009 n=6+6) ImportMutexSampleData/1K/2Kr/240/none/write-0-8 141ms ± 1% 119ms ± 2% -15.85% (p=0.004 n=5+6) ImportMutexSampleData/1K/2Kr/240/none/write-1-8 213ms ± 3% 171ms ± 3% -19.70% (p=0.002 n=6+6) |
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|---|---|---|
| .. | ||
| benchpretty | ||
| testdata | ||
| add.go | ||
| add_test.go | ||
| btree.go | ||
| btree_test.go | ||
| container_archetypes.go | ||
| container_stash.go | ||
| containers_btree.go | ||
| containers_slice.go | ||
| containers_test.go | ||
| filter.go | ||
| filter_internal_test.go | ||
| fuzz_test.go | ||
| fuzzer.go | ||
| generation_debug.go | ||
| generation_nodebug.go | ||
| inst.go | ||
| naive.go | ||
| naive_test.go | ||
| nop_inst.go | ||
| printutil.go | ||
| printutil_test.go | ||
| README.md | ||
| roaring.go | ||
| roaring_container_test.go | ||
| roaring_helpers_test.go | ||
| roaring_internal_test.go | ||
| roaring_nop_paranoia.go | ||
| roaring_nop_sentinel.go | ||
| roaring_nop_stats.go | ||
| roaring_paranoia.go | ||
| roaring_sentinel.go | ||
| roaring_stats.go | ||
| roaring_test.go | ||
| source.go | ||
| unmarshal_binary.go | ||
The Fuzzer
For complete documentation on go-fuzz, please see: https://github.com/dvyukov/go-fuzz
The fuzzer in relation to the roaring package checks the Bitmap.UnmarshalBinary function found in roaring.go. In order to use the fuzzer, you can follow these steps:
cd $GOPATH/src/github.com/pilosa/pilosa/roaring
go-fuzz-build ./
You must now make the workdir/corpus directory. This is achieved by:
mkdir workdir/corpus
The fuzzer needs some input to start the fuzzing with. Copy some sample Pilosa fragments into the workdir/corpus folder. For example:
cp ~/.pilosa/my-index/my-field/views/standard/fragments/0 workdir/corpus
Once you have copied your sample inputs, you are ready to run the fuzzer:
go-fuzz -bin=roaring-fuzz.zip -workdir=workdir -func=FuzzBitmapUnmarshalBinary
Understanding the Fuzzer Output
The fuzzer will output something similar to the follwoing:
2015/04/25 12:39:53 workers: 8, corpus: 124 (12s ago), crashers: 37, restarts: 1/15, execs: 35342 (2941/sec), cover: 403, uptime: 12s
The most important part of the output is the crashers and cover. The crashers records how many combinations were discovered that fail and the cover tells you how much code is being accessed.
For a complete explanation of the output, please see: https://github.com/dvyukov/go-fuzz.
The fuzzer will document the crashers in a folder labeled "crashers." It will record the fragment and the error that was produced in two separate files within this folder. This is the final product.
Happy Fuzzing!