David Roundy wrote:
On Thu, Jan 03, 2008 at 11:11:40AM +0000, Simon Marlow wrote:
Anyhow, could you retry this test with the above change in methodology, and let me know if (a) the pull is still slow the first time and (b) if it's much faster the second time (after the reverse unpull/pull)? I think I've done it in both directions now, and it got faster, but still much slower than darcs1:
$ time darcs2 unpull --from-tag 2007-09-25 -a Finished unpulling. 58.68s real 50.64s user 6.36s system 97% darcs2 unpull --from-tag 2007-09-25 -a $ time darcs2 pull -a ../ghc-darcs2 Pulling from "../ghc-darcs2"... Finished pulling and applying. 53.28s real 44.62s user 7.10s system 97% darcs2 pull -a ../ghc-darcs2
This is still an order of magnitude slower than darcs1 for the same operation. (these times are now on the local filesystem, BTW)
I've recently found the problem leading to this slowdown (I believe) and get about an order-of-magnitude improvement in the speed of a pull of 400 patches in the ghc repository. It turned out to be an issue that scaled with the size (width) of the repository, not with the number of patches (which had been the obvious suspect), which was causing trouble when applying to the pristine cache.
At this point, darcs-2 outperforms darcs-1 on most tests that I've tried, so it'd be a good time to find some more performance problems, if you can... and I don't doubt that there are more out there.
Certainly a lot faster, nice work! Though it's still not as fast as darcs-1 here. New figures: $ time darcs2 unpull --from-tag 2007-09-25 -a Finished unpulling. 18.83s real 15.27s user 1.53s system 89% darcs2 unpull --from-tag 2007-09-25 -a $ time darcs2 pull ../ghc-darcs2-other -a Finished pulling and applying. 10.38s real 7.69s user 1.50s system 88% darcs2 pull ../ghc-darcs2-other - I repeated the darcs-1 timings for comparison: $ time darcs unpull --from-tag 2007-09-25 -a Finished unpulling. 8.04s real 7.14s user 0.90s system 99% darcs unpull --from-tag 2007-09-25 -a $ time darcs pull ~/ghc-HEAD -a Finished pulling and applying. 7.90s real 4.90s user 0.98s system 74% darcs pull ~/ghc-HEAD -a In this case darcs-1 is pulling more patches (530 vs. 400), because I'm using the latest GHC HEAD repo. Also the darcs-1 repository being pulled from is on a different, NFS mounted, filesystem, whereas the darcs-2 timings were made using repos on the same local filesystem. In all cases I tried things a few times to let caches etc. fill up. Can you repeat these? Cheers, Simon