Hi Dscho, On Thu, Jan 31, 2019 at 10:04 PM Johannes Schindelin <Johannes.Schindelin@xxxxxx> wrote: > > Hi Elijah, > > as discussed at the Contributors' Summit, I ran p3400 as-is (i.e. with the > --am backend) and then with --keep-empty to force the interactive backend > to be used. Here are the best of 10, on my relatively powerful Windows 10 > laptop, with current `master`. > > With regular rebase --am: > > 3400.2: rebase on top of a lot of unrelated changes 5.32(0.06+0.15) > 3400.4: rebase a lot of unrelated changes without split-index 33.08(0.04+0.18) > 3400.6: rebase a lot of unrelated changes with split-index 30.29(0.03+0.18) > > with --keep-empty to force the interactive backend: > > 3400.2: rebase on top of a lot of unrelated changes 3.92(0.03+0.18) > 3400.4: rebase a lot of unrelated changes without split-index 33.92(0.03+0.22) > 3400.6: rebase a lot of unrelated changes with split-index 38.82(0.03+0.16) Awesome, thanks for checking that out. I ran on both linux and mac and saw similar relative performances. Comparing am-based rebase to an implied-interactive rebase on both linux and mac (with a version of git including en/rebase-merge-on-sequencer so that -m gives the same performance that you'd see with --keep-empty), I saw: On Linux: am-based rebase (without -m): 3400.2: rebase on top of a lot of unrelated changes 1.87(1.64+0.21) 3400.4: rebase a lot of unrelated changes without split-index 7.87(6.24+1.00) 3400.6: rebase a lot of unrelated changes with split-index 5.99(5.05+0.67) interactive-machinery rebase (with -m): 3400.2: rebase on top of a lot of unrelated changes 1.80(1.60+0.19) 3400.4: rebase a lot of unrelated changes without split-index 6.78(5.70+0.91) 3400.6: rebase a lot of unrelated changes with split-index 6.92(5.70+0.89) On Mac: am-based rebase (without -m): Test this tree ------------------------------------------------------------------------------- 3400.2: rebase on top of a lot of unrelated changes 2.68(1.68+0.68) 3400.4: rebase a lot of unrelated changes without split-index 8.89(5.86+2.94) 3400.6: rebase a lot of unrelated changes with split-index 7.87(5.35+2.51) interactive-machinery rebase (with -m): Test this tree ------------------------------------------------------------------------------- 3400.2: rebase on top of a lot of unrelated changes 1.99(1.61+0.77) 3400.4: rebase a lot of unrelated changes without split-index 8.63(5.38+3.38) 3400.6: rebase a lot of unrelated changes with split-index 9.36(5.53+3.95) > I then changed it to -m to test the current scripted version, trying to > let it run overnight, but my laptop eventually went to sleep and the tests > were not even done. I'll let them continue and report back. > > My conclusion after seeing these numbers is: the interactive rebase is > really close to the performance of the --am backend. So to me, it makes a > total lot of sense to switch --merge over to it, and to make --merge the > default. We still should investigate why the split-index performance is so > significantly worse, though. Cool, I'll update my patches to make --merge the default (building on top of en/rebase-merge-on-sequencer) and post it as an RFC. But yeah, we should also check into why the split-index performance becomes a bit worse with such a change. Thanks, Elijah
