Am 26.09.2013 12:16, schrieb Fredrik Gustafsson: > On Tue, Sep 24, 2013 at 11:50:16AM +0200, Karsten Blees wrote: >> Tests can be reproduced with 'time echo "perfhash[map] <method> 1000" | ./test-hashmap', see test-hashmap.c for definition of method flags. > > So I'm still curious about the actual performance improvements for git. > I runned git describe on the linux kernel with both the old hashmap and > this new one: > Performance was never the primary issue, the intention of the performance tests was to ensure that the new implementation doesn't *slow down* git. >From the original PATCH/RFC: - O(1) remove - builtin entry chaining - ready-to-use FNV-1 hash functions - unit test - additions are ~twice as fast - uses less memory So, the new implementation allows us to get rid of workarounds such as the CE_UNHASHED flag, duplicate entry chaining code and hash_name() implementations. It also addresses the memory usage FIXME in hash.h. The simplified API may help prevent bugs such as the broken entry chaining in name-hash.c (see commits 2548183, 395c735, 2092678). Maybe we can also replace some of the custom hash table implementations in attr.c, decorate.c, fast-import.c and object.c (to name just a few...). -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html