Re: [PATCH 5/5] (BROKEN) get_merge_bases_many(): walk from many tips in parallel
- From
Junio C Hamano <gitster@pobox.com>
- Date
- Aug 28, 2012, 23:39 UTC
- Message-ID
- <7vvcg2y4bk.fsf@alter.siamese.dyndns.org>
- In-Reply-To
- <7v8vcyzomw.fsf@alter.siamese.dyndns.org>
Junio C Hamano <gitster@pobox.com> writes:
Show 41 quoted lines
> Junio C Hamano <gitster@pobox.com> writes:
>
>> Junio C Hamano <gitster@pobox.com> writes:
>>
>>> for (i = 0; i < cnt; i++) {
>>> - if (rslt[i])
>>> + /*
>>> + * Is rslt[i] an ancestor of any of the others?
>>> + * then it is not interesting to us.
>>> + */
>>> + for (j = 0; j < i; j++)
>>> + others[j] = rslt[j];
>>> + for (j = 1 + 1; j < cnt; j++)
>>
>> s/1 + 1/i + 1/;
>>
>> With that, all tests seem to pass ;-)
>
> "git merge-base" itself seems to have more room for improvement.
> Trying to recompute bases for recent 200 merges in the kernel
> history with the attached script does not show any improvement with
> or without the series on top of recent "master". Correctnesswise it
> seems to be OK, though---I get byte-for-byte identical output.
>
> -- >8 --
> #!/bin/sh
>
> git rev-list --committer=torvalds@linux-foundation.org \
> --max-parents=2 --min-parents=2 --parents v3.5..v3.6-rc2 >RL
>
> cmd='
> while read result parent1 parent2
> do
> $GIT merge-base $parent1 $parent2
> done <RL
> '
>
> GIT="rungit master" time sh -c "$cmd" >:stock
> GIT=../git.git/git time sh -c "$cmd" >:optim
> cmp :stock :optim
> -- 8< --I have this suspicion that it is spending most of its time in insert-by-date. Luckily, merge_bases_many() is totally outside of the usual revision traversal and its use of the commit list is pretty well isolated.
Peff, can I interest you into resurrecting your $gmane/174007 and $gmane/174008 (we do not need pop_commit_from_queue() in the latter; everything can stay as static to commit.c for now) to see how well priority queue based approach would perform?