From: bdowning@lavos.net (Brian Downing)
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Steffen Prohaska <prohaska@zib.de>,
Johannes Schindelin <Johannes.Schindelin@gmx.de>,
Junio C Hamano <gitster@pobox.com>,
Git Mailing List <git@vger.kernel.org>,
msysgit@googlegroups.com
Subject: Re: [PATCH] Avoid running lstat(2) on the same cache entry.
Date: Sun, 20 Jan 2008 14:03:10 -0600 [thread overview]
Message-ID: <20080120200310.GK22503@lavos.net> (raw)
In-Reply-To: <alpine.LFD.1.00.0801200942191.2957@woody.linux-foundation.org>
On Sun, Jan 20, 2008 at 10:20:46AM -0800, Linus Torvalds wrote:
> But I guess that was a bit optimistic. On Linux, we still had about 50%
> user time, and I guess the same is _largely_ true on Windows. Cutting the
> system time in half only gives you about a quarter performance
> improvement, and I was just incorrect in expecting system calls to be the
> limiting factor.
>
> [...]
>
> fnmatch? It's certainly visible on Linux, I wonder if the Windows/OSX
> version is more expensive due to trying to be case-insensitive or
> something?
Windows (msys) Git, with the lstat patch and on my 15433-file test case,
is at least 90-95% system time. I don't have any good tools for
measuring this, but just using the silly performance monitor you get
with ctrl-alt-del and enabling the "View -> Show Kernel Times" curve on
the graph shows this fact pretty clearly.
I think this shows that:
1. There's not much overhead in msysGit's stat wrapper at all. It gets
converted quite efficiently to native Windows calls.
2. Windows really sucks at filesystem ops. Film at 11.
One thing I dimly recall is that the nightmare interface of
FindFirstFile/FindNextFile (which I assume is what is actually getting
called for opendir/readdir) actually returns some stat information with
each file. Would it be possible to use that directly in some cases
rather than taking an extra stat call to get it?
-bcd
next prev parent reply other threads:[~2008-01-20 20:03 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-01-19 3:25 Updated in-memory index cleanup Linus Torvalds
2008-01-19 7:42 ` [PATCH] index: be careful when handling long names Junio C Hamano
2008-01-19 7:45 ` [PATCH] Avoid running lstat(2) on the same cache entry Junio C Hamano
2008-01-19 19:47 ` Linus Torvalds
2008-01-19 19:58 ` Linus Torvalds
2008-01-20 1:22 ` Linus Torvalds
2008-01-20 1:34 ` Linus Torvalds
2008-01-20 1:48 ` Johannes Schindelin
2008-01-20 2:02 ` Linus Torvalds
2008-01-20 10:33 ` Steffen Prohaska
2008-01-20 14:15 ` Johannes Schindelin
2008-01-21 0:18 ` Junio C Hamano
2008-01-20 15:10 ` Steffen Prohaska
2008-01-20 15:18 ` Johannes Schindelin
2008-01-20 15:19 ` [PATCH] Also use unpack_trees() in do_diff_cache() Johannes Schindelin
2008-01-20 20:32 ` Linus Torvalds
2008-01-20 21:53 ` Linus Torvalds
2008-01-20 23:34 ` Johannes Schindelin
2008-01-20 23:58 ` Linus Torvalds
2008-01-21 0:19 ` Johannes Schindelin
2008-01-20 15:21 ` [PATCH] Try to resurrect the handling for 'diff-index -m' Johannes Schindelin
2008-01-20 18:20 ` [PATCH] Avoid running lstat(2) on the same cache entry Linus Torvalds
2008-01-20 20:03 ` Brian Downing [this message]
2008-01-20 21:40 ` Steffen Prohaska
2008-01-20 22:09 ` Linus Torvalds
2008-01-20 2:42 ` Johannes Schindelin
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=20080120200310.GK22503@lavos.net \
--to=bdowning@lavos.net \
--cc=Johannes.Schindelin@gmx.de \
--cc=git@vger.kernel.org \
--cc=gitster@pobox.com \
--cc=msysgit@googlegroups.com \
--cc=prohaska@zib.de \
--cc=torvalds@linux-foundation.org \
/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).