On Thu, Aug 19, 2010 at 11:38 PM, Johan Corveleyn <jcor...@gmail.com> wrote: > Feh, I just redid my apr_time_now+printf profiling with a release > build (of trunk), instead of a debug build, and that makes a *big* > difference. Total time of the svn_diff_diff call is now down to ~300 > ms. Still a lot slower than GNU diff (78 ms), but a lot better than > with the debug build. That will teach me not to do performance tests > with a debug build. > > Still, the challenge holds: why is svn diff ~4 times slower than GNU diff? > > Also, still puzzling to me: why does datasource_open take so long in > the "modified" case? Now it takes twice as long as the while loop ...
@#...@#!!! /me bangs head against wall The slowness of datasource_open was because of my antivirus (AVG free edition). After disabling it, it's completely gone. Running a release build, with antivirus disabled, and minimal instrumentation brings svn diff performance (after a couple of runs) more or less on par with GNU diff: $ time svn diff bigfile.xml Starting diff ... (entered svn_diff_diff in diff.c) Diff finished in 78125 usec (78 millis) [snip] real 0m0.359s user 0m0.015s sys 0m0.031s I guess this closes this thread ... on to more useful stuff. There is no point in trying to optimize svn diff, so I guess blame can only be sped up by more fundamental changes (i.e. avoiding diffs, which still amount to ~90% of blame time on the client side). Sorry for any wasted time. (on the bright side, I learned quite a lot about accurately measuring performance) Cheers, -- Johan
