Hi all, perhaps this will turn out to be a bit academic, anyway... I'm almost ready to release qgit-2.1, a lot of improvements went in but still I cannot beat the speed of stable qgit-1.5 series. I really profiled this puppy and I think qgit-2.1 is _internally_ much faster then qgit-1.5, but at the end of the day qgit-1.5 is about 13% faster then the new 2.1 at loading repositories. The loading speed is the sum of two factors: - speed of underlying git-rev-list / git-log command - qgit overhead in parsing and storing the git plumbing outpt I think qgit-2.0 code is much more efficient then the old one because the overhead went down from 17% of qgit-1.5 to current 6% of qgit-2.1, it means that opening and loading a repository with qgit-2.1 is only 6% slower then running the underlying git command from the command line. So the problem seems to be in the underlying command that for qgit-1.5 is git-rev-list while for new qgit-2.1 is git-log To have some numbers I have tested on the Linux repository with the actual git commands used by the two versions of qgit: [marco@localhost linux-2.6]$ git --version git version 1.5.4-rc1.GIT [marco@localhost linux-2.6]$ time git log --topo-order --no-color --parents --boundary -z --log-size --pretty=format:"%m%HX%PX%n%an<%ae>%n%at%n%s%n%b" HEAD > /dev/null 3.60user 0.09system 0:03.70elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k 0inputs+0outputs (0major+27156minor)pagefaults 0swaps [marco@localhost linux-2.6]$ time git rev-list --topo-order --no-color --parents --boundary -z --header HEAD > /dev/null 2.89user 0.08system 0:02.98elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k 0inputs+0outputs (0major+27156minor)pagefaults 0swaps [ BTW, yes I have a new laptop! ;-) ] Note that the output is smaller for git-log because --pretty=format asks for less info then the --header option used by git-rev-list. To be precise, output is 57.113.153 bytes for git-rev-list against 41.755.328 bytes for git-log. So the bottom line is that git-log is 24% slower then git-rev-list although size of its output is 36% smaller! Could someone be so kind to explain me why these differences? I'm not so confident with git-log /git-rev-list internals. Thanks Marco - 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
