From: David Kastrup <dak@gnu.org>
To: Stefan Zager <szager@chromium.org>
Cc: Duy Nguyen <pclouds@gmail.com>, Git Mailing List <git@vger.kernel.org>
Subject: Re: Make the git codebase thread-safe
Date: Wed, 12 Feb 2014 19:50:43 +0100 [thread overview]
Message-ID: <87y51g88sc.fsf@fencepost.gnu.org> (raw)
In-Reply-To: <CAHOQ7J8gvwpwJV2mBPDaARu3cQ54-ZDQ6iGOwKuJRr9Z+XBL7g@mail.gmail.com> (Stefan Zager's message of "Wed, 12 Feb 2014 10:12:20 -0800")
Stefan Zager <szager@chromium.org> writes:
> On Tue, Feb 11, 2014 at 6:11 PM, Duy Nguyen <pclouds@gmail.com> wrote:
>>
>> I have no comments about thread safety improvements (well, not yet).
>> If you have investigated about git performance on chromium
>> repositories, could you please sum it up? Threading may be an option
>> to improve performance, but it's probably not the only option.
>
> Well, the painful operations that we use frequently are pack-objects,
> checkout, status, and blame.
Have you checked the patch in
<URL:http://thread.gmane.org/gmane.comp.version-control.git/241448> and
followups,
Message-ID: <1391454849-26558-1-git-send-email-dak@gnu.org>?
While this does not yet support -M and -C options, it's conceivable that
you don't use them in your server/scripts.
> Anything on Windows that touches a lot of files is miserable due to
> the usual file system slowness on Windows, and luafv.sys (the UAC file
> virtualization driver) seems to make it much worse.
There is an obvious solution here... Dedicated hardware is not that
expensive. Virtualization will always have a price.
> Blame is something that chromium and blink developers use heavily, and
> it is not unusual for a blame invocation on the blink repository to
> run for 30 seconds. It seems like it should be possible to
> parallelize blame, but it requires pack file operations to be
> thread-safe.
Really, give the above patch a try. I am taking longer to finish it
than anticipated (with a lot due to procrastination but that is,
unfortunately, a large part of my workflow), and it's cutting into my
"paychecks" (voluntary donations which to a good degree depend on timely
and nontrivial progress reports for my freely available work on GNU
LilyPond).
Note that it looks like the majority of the remaining time on GNU/Linux
tends to be spent in system time: I/O time, memory management. And I
have an SSD drive. When using packed repositories of considerable size,
decompression comes into play as well. I don't think that you can hope
to get noticeably higher I/O throughput by multithreading, so really,
really, really consider dedicated hardware running on a native Linux
file system.
--
David Kastrup
next prev parent reply other threads:[~2014-02-12 18:50 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-02-12 1:54 Make the git codebase thread-safe Stefan Zager
2014-02-12 2:02 ` Robin H. Johnson
2014-02-12 3:43 ` Duy Nguyen
2014-02-12 11:00 ` Karsten Blees
2014-02-12 23:03 ` Mike Hommey
2014-02-13 0:06 ` Karsten Blees
2014-02-12 18:15 ` Stefan Zager
2014-02-12 2:11 ` Duy Nguyen
2014-02-12 18:12 ` Stefan Zager
2014-02-12 18:33 ` Matthieu Moy
2014-02-12 18:39 ` Stefan Zager
2014-02-12 18:50 ` David Kastrup [this message]
2014-02-12 19:02 ` Stefan Zager
2014-02-12 19:15 ` David Kastrup
2014-02-12 23:09 ` Mike Hommey
2014-02-13 6:04 ` David Kastrup
2014-02-13 9:34 ` Mike Hommey
2014-02-13 9:48 ` Mike Hommey
2014-02-13 8:30 ` David Kastrup
2014-02-12 20:06 ` Junio C Hamano
2014-02-12 20:27 ` Stefan Zager
2014-02-12 23:05 ` Junio C Hamano
2014-02-12 11:59 ` Erik Faye-Lund
2014-02-12 18:20 ` Stefan Zager
2014-02-12 18:27 ` Erik Faye-Lund
2014-02-12 18:34 ` Stefan Zager
2014-02-12 18:37 ` Erik Faye-Lund
2014-02-12 19:22 ` Karsten Blees
2014-02-12 19:30 ` Stefan Zager
2014-02-13 8:27 ` Johannes Sixt
2014-02-13 8:38 ` David Kastrup
2014-02-13 18:40 ` Stefan Zager
2014-02-13 18:38 ` Zachary Turner
2014-02-13 22:51 ` Karsten Blees
2014-02-13 22:53 ` Stefan Zager
2014-02-13 23:09 ` Zachary Turner
2014-02-14 19:04 ` Karsten Blees
[not found] ` <CAAErz9g7ND1htfk=yxRJJLbSEgBi4EV_AHC9uDRptugGWFWcXw@mail.gmail.com>
2014-02-14 19:16 ` Zachary Turner
2014-02-14 23:10 ` Karsten Blees
2014-02-15 0:45 ` Duy Nguyen
2014-02-15 0:50 ` Stefan Zager
2014-02-15 0:56 ` Duy Nguyen
2014-02-15 1:15 ` Zachary Turner
2014-02-15 1:39 ` Duy Nguyen
2014-02-18 17:55 ` Junio C Hamano
2014-02-18 18:14 ` Zachary Turner
2014-02-14 19:52 ` Stefan Zager
2014-02-14 21:49 ` Stefan Zager
2014-02-13 1:42 ` brian m. carlson
2019-04-02 0:52 ` Matheus Tavares
2019-04-02 1:07 ` Duy Nguyen
2019-04-02 10:30 ` David Kastrup
2019-04-02 11:35 ` Duy Nguyen
2019-04-02 11:52 ` David Kastrup
2019-04-02 19:06 ` Matheus Tavares Bernardino
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