From: Matheus Tavares Bernardino <matheus.bernardino@usp.br>
To: Duy Nguyen <pclouds@gmail.com>
Cc: "Jeff King" <peff@peff.net>,
"Christian Couder" <christian.couder@gmail.com>,
"Thomas Gummerer" <t.gummerer@gmail.com>,
git <git@vger.kernel.org>,
"Оля Тележная" <olyatelezhnaya@gmail.com>,
"Elijah Newren" <newren@gmail.com>,
"Tanushree Tumane" <tanushreetumane@gmail.com>
Subject: Re: Questions on GSoC 2019 Ideas
Date: Tue, 5 Mar 2019 20:46:50 -0300 [thread overview]
Message-ID: <CAHd-oW4LsyZOgHYgKaACX8AtzbA8pBpFUPWSF3GF6XxA_HKfjA@mail.gmail.com> (raw)
In-Reply-To: <CACsJy8D-eQUGFsu4_cB9FE6gAo2d68EF_x2ze3YLXKAxYJfhSQ@mail.gmail.com>
This exercise of estimating a good spot to gain performance with
parallelism at git seems more difficult than I thought, firstly. Also,
I'm not that familiar yet with git packing (neither with the sections
of it that could benefit from parallelism). So could anyone point me
some good references on this, where I could study and maybe come back
with more valuable suggestions?
On Tue, Mar 5, 2019 at 9:57 AM Duy Nguyen <pclouds@gmail.com> wrote:
>
> On Tue, Mar 5, 2019 at 11:51 AM Jeff King <peff@peff.net> wrote:
> > > processing power from multiple cores, but about _not_ blocking. I
> > > think one example use case here is parallel checkout. While one thread
> > > is blocked by pack access code for whatever reason, the others can
> > > still continue doing other stuff (e.g. write the checked out file to
> > > disk) or even access the pack again to check more things out.
> >
Hmm, you mean distributing the process of inflating, reconstructing
deltas and checking out files between the threads? (having each one
doing the process for a different file?)
> > I'm not sure if it would help much for packs, because they're organized
> > to have pretty good cold-cache read-ahead behavior. But who knows until
> > we measure it.
> >
> > I do suspect that inflating (and delta reconstruction) done in parallel
> > could be a win for git-grep, especially if you have a really simple
> > regex that is quick to search.
>
> Maybe git-blame too. But this is based purely on me watching CPU
> utilization of one command with hot cache. For git-blame though, diff
> code as to be thread safe too but that's another story.
I don't know if this relates to parallelizing pack access, but I
thought that sharing this with you all could perhaps bring some new
insights (maybe even on parallelizing some other git section): I asked
my friends who contribute to the Linux Kernel what git commands seems
to take longer during their kernel work, and the answers were:
- git log and git status, sometimes
- using pager's search at git log
- checking out to an old commit
- git log --oneline --decorate --graph
next prev parent reply other threads:[~2019-03-05 23:47 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-28 21:46 Questions on GSoC 2019 Ideas Matheus Tavares Bernardino
2019-02-28 22:07 ` Christian Couder
2019-03-01 9:30 ` Duy Nguyen
2019-03-02 15:09 ` Thomas Gummerer
2019-03-03 7:18 ` Christian Couder
2019-03-03 10:12 ` Duy Nguyen
2019-03-03 10:17 ` Duy Nguyen
2019-03-05 4:51 ` Jeff King
2019-03-05 12:57 ` Duy Nguyen
2019-03-05 23:46 ` Matheus Tavares Bernardino [this message]
2019-03-06 10:17 ` Duy Nguyen
2019-03-12 0:18 ` Matheus Tavares Bernardino
2019-03-12 10:02 ` Duy Nguyen
2019-03-12 10:11 ` Duy Nguyen
2019-04-04 1:15 ` Matheus Tavares Bernardino
2019-04-04 7:56 ` Christian Couder
2019-04-04 8:20 ` Mike Hommey
2019-04-05 16:28 ` Matheus Tavares Bernardino
2019-04-07 23:40 ` Christian Couder
2019-03-05 23:03 ` Matheus Tavares Bernardino
2019-03-06 23:17 ` Thomas Gummerer
2019-03-03 10:03 ` Duy Nguyen
2019-03-03 16:12 ` Thomas Gummerer
2019-03-01 15:20 ` 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=CAHd-oW4LsyZOgHYgKaACX8AtzbA8pBpFUPWSF3GF6XxA_HKfjA@mail.gmail.com \
--to=matheus.bernardino@usp.br \
--cc=christian.couder@gmail.com \
--cc=git@vger.kernel.org \
--cc=newren@gmail.com \
--cc=olyatelezhnaya@gmail.com \
--cc=pclouds@gmail.com \
--cc=peff@peff.net \
--cc=t.gummerer@gmail.com \
--cc=tanushreetumane@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).