Subject: Re: Emacs repository benchmark: bzr and git (rerun)
Newsgroups: gmane.comp.version-control.bazaar-ng.general, gmane.emacs.devel
Date: 2008-03-19 11:37:42 GMT (37 weeks, 15 hours and 54 minutes ago)
Teemu Likonen kirjoitti: > I did some benchmarking in git and bzr repositories of Emacs. Some > numbers: 89711 revisions (by "git log --pretty=oneline | wc -l"), > 2825 files. Both repositories seem to have just linear history > converted from CVS repo. Both have the same head revision which is > 481c2a1e31f32c8aa0fb6d504575b75a18537788 (git) and > revid:cvs-1:tsdh-20080318180244-lxbzttdnh6ecqbka (bzr). > > Repositories/branches are pulled from here: > git: git://git.sv.gnu.org/emacs.git > bzr: http://bzr.notengoamigos.org/emacs/trunk/ > > My system is AMD Sempron 3000+ with 2 GB memory and it's running > Debian GNU/Linux 4.0. I'm using the latest development versions of > both git (1.5.5.rc0.6.gdeda) and bzr (1.4dev). I just measured with > 'time' command how long it takes to run certain commands. Hey! I realised that the emacs bzr repository was not fully optimized with "bzr pack" command. By running this command it really improves the performance of bzr; now I'm getting similar numbers as some of you. I really apologise for the misleading information I have spread. I want to correct my mistakes by running my tests again (see below). This raises questions though. I had downloaded the premade emacs bzr repo from <http://bzr.notengoamigos.org/> and it seems to have its repo pretty much optimized since it performs much better than my previous benchmark. I had done almost nothing with the repository after that, just some bzr-pulls and performance tests. How come the emacs bzr repository slows down so much and so quickly? My experience is that you definitely want to run "bzr pack" quite often. Anyway, here are the same tests with bzr-packed and git-gc'd repositories. This test shows that both have improved their performance, especially bzr. I did run all the tests three times to see if caches have effect. They didn't: all the three runs gave very much the same numbers. I picked up the best one anyway. Again, I'm really sorry about my previous tests. > Viewing history > --------------- I want to point out that in git you can always see the log _immediately_, no matter how long it takes to display the whole thing. In bzr these numbers reflect pretty much the time to get anything visible at all after entering the command. > The complete history: > > $ time git log >/dev/null > real 0m5.741s > > $ time bzr log >/dev/null > real 3m15.708s git: 0m3.348s bzr: 1m15.143s > Last 100 revisions: > > $ time git log -100 >/dev/null > real 0m0.011s > > $ time bzr log -l100 >/dev/null > real 2m10.270s git: 0m0.009s bzr: 0m26.562s > Last 10 revisions: > > $ time git log -10 >/dev/null > real 0m0.007s > > $ time bzr log -l10 >/dev/null > real 2m9.163s git: 0m0.005s bzr: 0m25.519s > The complete history of a single file: > > $ time git log src/keymap.c >/dev/null > real 0m9.240s > (The same as above but with detecting and following possible > renames:) $ time git log --follow src/keymap.c >/dev/null > real 0m17.891s > > $ time bzr log src/keymap.c >/dev/null > real 3m35.431s git: 0m5.127s git: 0m8.953s (with --follow) bzr: 0m55.461s > Differences between revisions > ----------------------------- > View changes introduced in given revision: > > (This shows also the commit message, author and date.) > $ time git show 2635714f3dac5f24eb1997cbf97285810f6799c0 >/dev/null > real 0m0.012s > > $ time bzr diff -c revid:cvs-1:wohler-20080318101724-c3ofm3vslli3wfwl > >/dev/null real 2m40.467s git: 0m0.010s bzr: 0m23.315s > Show differences between two revisions: > > $ time git diff HEAD~10..HEAD~4 >/dev/null > real 0m0.076s > > $ time bzr diff -r -11..-5 >/dev/null > real 2m44.214s git: 0m0.068s bzr: 0m24.140s > $ time git diff HEAD~4.. >/dev/null > real 0m0.072s > > $ time bzr diff -r -5.. >/dev/null > real 1m21.836s git: 0m0.060s bzr: 0m12.889s > Creating a branch > ----------------- > > With git I chose "git checkout -b" instead of "git branch" because > the former also checks out the files as does "bzr branch". The bzr > branch is created inside the same shared repository so that the > common objects are shared. > > > Create new topic branch based on the head revision of the main > development branch: > > $ time git checkout -b topic master >/dev/null > real 0m0.062s > > $ time bzr branch trunk topic >/dev/null > real 0m7.249s git: 0m0.043s bzr: 0m4.504s > Create new topic branch based on earlier revision of main development > branch: > > $ time git checkout -b topic master~4 >/dev/null > real 0m0.085s > > $ time bzr branch -r -5 trunk topic >/dev/null > real 2m51.551s git: 0m0.062s bzr: 0m30.120s > Compare branches' commit histories > ---------------------------------- > > In above benchmark I created branch 'topic' which is based on earlier > revision of main development branch. In this test I compared commands > which display commits that are missing from 'topic' branch compared > to the main development branch (four commits in total). > > > $ time git log topic..master >/dev/null > real 0m0.006s > > $ time bzr missing --theirs-only ../trunk >/dev/null > real 18m25.173s git: 0m0.004s bzr: 13m48.239s > Annotate/blame a file (src/keymap.c) > ------------------------------------ > > $ time git blame src/keymap.c >/dev/null > real 0m8.753s > > $ time bzr blame src/keymap.c >/dev/null > real 0m58.296s git: 0m7.954s bzr: 0m17.114s