On Wed, Oct 03, 2018 at 03:18:05PM -0400, Jeff King wrote: > I'm still excited about the prospect of a bloom filter for paths which > each commit touches. I think that's the next big frontier in getting > things like "git log -- path" to a reasonable run-time.
There is certainly potential there. With a (very) rough PoC experiment, a 8MB bloom filter, and a carefully choosen path I can achieve a nice, almost 25x speedup: $ time git rev-list --count HEAD -- t/valgrind/valgrind.sh 6 real 0m1.563s user 0m1.519s sys 0m0.045s $ time GIT_USE_POC_BLOOM_FILTER=y ~/src/git/git rev-list --count HEAD -- t/valgrind/valgrind.sh 6 real 0m0.063s user 0m0.043s sys 0m0.020s bloom filter total queries: 16269 definitely not: 16195 maybe: 74 false positives: 64 fp ratio: 0.003934 But I'm afraid it will take a while until I get around to turn it into something presentable...
