Fix built-in rebase perf regression #72
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Submitted as pull.72.git.gitgitgadget@gmail.com |
The same clean-up code is repeated quite a few times; Let's DRY up the code some. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Currently, we only accept the flag indicating whether the HEAD should be detached not. In the next commit, we want to introduce another flag: to toggle between emulating `reset --hard` vs `checkout -q`. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
When we converted a `git checkout -q $onto^0` call to use `reset_head()`, we inadvertently incurred a change from a twoway_merge to a oneway_merge, as if we wanted a `git reset --hard` instead. This has performance ramifications under certain, though, as the oneway_merge needs to lstat() every single index entry whereas twoway_merge does not. So let's go back to the old behavior. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
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Submitted as pull.72.v2.git.gitgitgadget@gmail.com |
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This patch series was integrated into pu via git@bb6dd0e. |
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This patch series was integrated into next via git@bb6dd0e. |
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This patch series was integrated into master via git@bb6dd0e. |
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This patch series was integrated into maint via git@bb6dd0e. |
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Closed via bb6dd0e. |
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In our tests with large repositories, we noticed a serious regression of the performance of
git rebasewhen using the built-in vs the shell script version. It boils down to an incorrect conversion of agit checkout -q: instead of using atwoway_mergeasgit checkoutdoes, we used aoneway_mergeasgit resetdoes. The latter, however, callslstat()on all files listed in the index, while the former essentially looks only at the files that are different between the given two revisions.Let's reinstate the original behavior by introducing a flag to the
reset_head()function to indicate whether we want to emulatereset --hard(in which case we use theoneway_merge, otherwise we usetwoway_merge).Changes vs v1:
goto leave_reset_head.descarray is not initialized to all-zero, to avoid bogus addresses being passed tofree().detach_headandreset_hardparameters have been consolidated into aflagsparameter.reset_head()function once again only initializeshead_oidwhen needed.