From: Junio C Hamano <gitster@pobox.com>
To: Martin von Zweigbergk <martinvonz@gmail.com>
Cc: git@vger.kernel.org
Subject: Re: [PATCH] oneway_merge(): only lstat() when told to update worktree
Date: Thu, 20 Dec 2012 12:02:53 -0800 [thread overview]
Message-ID: <7vk3sc4hle.fsf@alter.siamese.dyndns.org> (raw)
In-Reply-To: <1356025067-5396-1-git-send-email-martinvonz@gmail.com> (Martin von Zweigbergk's message of "Thu, 20 Dec 2012 09:37:47 -0800")
Martin von Zweigbergk <martinvonz@gmail.com> writes:
> Although the subject line of 613f027 (read-tree -u one-way merge fix
> to check out locally modified paths., 2006-05-15) mentions "read-tree
> -u", it did not seem to check whether -u was in effect. Not checking
> whether -u is in effect makes e.g. "read-tree --reset" lstat() the
> worktree, even though the worktree stat should not matter for that
> operation.
>
> This speeds up e.g. "git reset" a little on the linux-2.6 repo (best
> of five, warm cache):
>
> Before After
> real 0m0.288s 0m0.233s
> user 0m0.190s 0m0.150s
> sys 0m0.090s 0m0.080s
> ---
Sign-off?
I briefly discussed this with Martin in person and came to the same
conclusion. To me this looks like an obvious performance fix, but an
independent code audit catches our mistakes is of course welcomed.
Thanks.
> I am very unfamiliar with this part of git, so my attempt at a
> motivation may be totally off.
>
> I have another twenty-or-so patches to reset.c coming up that take the
> timings down to around 90 ms, but this patch was quite unrelated to
> that. Those other patches actually make this patch pointless for "git
> reset" (it takes another path), but I hope this is still a good change
> for other operations that use oneway_merge.
>
> unpack-trees.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/unpack-trees.c b/unpack-trees.c
> index 6d96366..61acc5e 100644
> --- a/unpack-trees.c
> +++ b/unpack-trees.c
> @@ -1834,7 +1834,7 @@ int oneway_merge(struct cache_entry **src, struct unpack_trees_options *o)
>
> if (old && same(old, a)) {
> int update = 0;
> - if (o->reset && !ce_uptodate(old) && !ce_skip_worktree(old)) {
> + if (o->reset && o->update && !ce_uptodate(old) && !ce_skip_worktree(old)) {
> struct stat st;
> if (lstat(old->name, &st) ||
> ie_match_stat(o->src_index, old, &st, CE_MATCH_IGNORE_VALID|CE_MATCH_IGNORE_SKIP_WORKTREE))
next prev parent reply other threads:[~2012-12-20 20:03 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-20 17:37 [PATCH] oneway_merge(): only lstat() when told to update worktree Martin von Zweigbergk
2012-12-20 20:02 ` Junio C Hamano [this message]
2012-12-20 21:03 ` [PATCH v2] " Martin von Zweigbergk
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
List information: http://vger.kernel.org/majordomo-info.html
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=7vk3sc4hle.fsf@alter.siamese.dyndns.org \
--to=gitster@pobox.com \
--cc=git@vger.kernel.org \
--cc=martinvonz@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
Code repositories for project(s) associated with this public inbox
https://80x24.org/mirrors/git.git
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).