From: Jeff King <peff@peff.net>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Junio C Hamano <gitster@pobox.com>,
Marc Stevens <marc.stevens@cwi.nl>,
Dan Shumow <danshu@microsoft.com>,
Git Mailing List <git@vger.kernel.org>
Subject: Re: [PATCH] Put sha1dc on a diet
Date: Wed, 1 Mar 2017 14:53:02 -0500 [thread overview]
Message-ID: <20170301195302.3pybakmjqztosohj@sigill.intra.peff.net> (raw)
In-Reply-To: <CA+55aFx1wAS-nHS2awuW2waX=cvig4UoZqmN5H3v93yDE7ukyQ@mail.gmail.com>
On Wed, Mar 01, 2017 at 10:49:55AM -0800, Linus Torvalds wrote:
> That said, I think that it would be lovely to just default to
> USE_SHA1DC and just put the whole attack behind us. Yes, it's slower.
> No, it doesn't really seem to matter that much in practice.
My biggest concern is the index-pack operation. Try this:
time git clone --no-local --bare linux tmp.git
with and without USE_SHA1DC. I get:
[w/ openssl]
real 1m52.307s
user 2m47.928s
sys 0m14.992s
[w/ sha1dc]
real 3m4.043s
user 6m16.412s
sys 0m13.772s
That's real latency the user will see. It's hard to break it down,
though. The actual "receiving" phase is generally going to be network
bound. The delta-resolution that happens afterwards is totally local and
CPU-bound (but does run in parallel).
And of course this repository tends to the larger side (though certainly
there are bigger ones), and you only feel the pain on clone or when
doing an initial push, not day-to-day.
So maybe we just suck it up and accept that it's a bit slower.
-Peff
next prev parent reply other threads:[~2017-03-01 20:02 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-01 0:30 [PATCH] Put sha1dc on a diet Linus Torvalds
2017-03-01 18:42 ` Junio C Hamano
2017-03-01 18:49 ` Linus Torvalds
2017-03-01 19:41 ` Junio C Hamano
2017-03-01 21:56 ` Johannes Schindelin
2017-03-01 22:05 ` Junio C Hamano
2017-03-01 22:16 ` Linus Torvalds
2017-03-01 22:51 ` Johannes Schindelin
2017-03-01 23:05 ` Linus Torvalds
2017-03-01 23:19 ` Jeff King
2017-03-02 6:10 ` Duy Nguyen
2017-03-02 14:45 ` Johannes Schindelin
2017-03-02 16:35 ` Linus Torvalds
2017-03-02 18:37 ` Jeff Hostetler
2017-03-02 19:04 ` Linus Torvalds
2017-03-02 14:39 ` Johannes Schindelin
2017-03-02 14:37 ` Johannes Schindelin
2017-03-01 19:53 ` Jeff King [this message]
[not found] ` <CA+55aFwf3sxKW+dGTMjNAeHMOf=rvctEQohm+rbhEb=e3KLpHw@mail.gmail.com>
2017-03-01 20:34 ` Jeff King
[not found] ` <CA+55aFwr1jncrk-cekn0Y8rs_S+zs7RrgQ-Jb-ZbgCvmVrHT_A@mail.gmail.com>
2017-03-01 23:13 ` Jeff King
2017-03-01 23:38 ` Linus Torvalds
2017-03-02 1:31 ` Dan Shumow
2017-03-02 4:38 ` Junio C Hamano
2017-03-04 1:07 ` Dan Shumow
2017-03-13 15:13 ` Jeff King
[not found] ` <CY1PR0301MB2107B3C5131D5DC7F91A0147C4250@CY1PR0301MB2107.namprd03.prod.outlook.com>
[not found] ` <CY1PR0301MB2107876B6E47FBCF03AB1EA1C4250@CY1PR0301MB2107.namprd03.prod.outlook.com>
2017-03-13 19:48 ` Jeff King
2017-03-13 20:12 ` Marc Stevens
2017-03-13 20:20 ` Linus Torvalds
2017-03-13 20:47 ` Marc Stevens
2017-03-13 21:00 ` Jeff King
2017-03-13 21:15 ` Marc Stevens
2017-03-16 18:22 ` Marc Stevens
2017-03-16 22:06 ` Jeff King
2017-03-16 22:07 ` Dan Shumow
2017-03-01 19:07 ` Jeff King
2017-03-01 19:10 ` Linus Torvalds
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=20170301195302.3pybakmjqztosohj@sigill.intra.peff.net \
--to=peff@peff.net \
--cc=danshu@microsoft.com \
--cc=git@vger.kernel.org \
--cc=gitster@pobox.com \
--cc=marc.stevens@cwi.nl \
--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).