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From: Jeff King <peff@peff.net>
To: Duy Nguyen <pclouds@gmail.com>
Cc: David Lang <david@lang.hm>,
	Koosha Khajehmoogahi <koosha.khajeh@gmail.com>,
	git <git@vger.kernel.org>
Subject: Re: Multi-threaded 'git clone'
Date: Mon, 16 Feb 2015 19:56:32 -0500	[thread overview]
Message-ID: <20150217005632.GA13001@peff.net> (raw)
In-Reply-To: <CACsJy8Brnu7rBxtCq_ac58BW7dOK=wtzMxVL-gsOUXJB2Jss9w@mail.gmail.com>

On Tue, Feb 17, 2015 at 06:16:39AM +0700, Duy Nguyen wrote:

> On Mon, Feb 16, 2015 at 10:47 PM, Jeff King <peff@peff.net> wrote:
> > Each clone generates the pack on the fly
> > based on what's on disk and streams it out. It should _usually_ be the
> > same, but there's nothing to guarantee byte-for-byte equality between
> > invocations.
> 
> It's usually _not_ the same. I tried when I wanted to produce stable
> packs. The first condition is single-threaded pack-objects. Otherwise
> thread scheduler could make object order unpredictable.

True. If you keep your server repositories fully packed, that eliminates
the delta search (and/or makes it feasible to turn pack.threads to 1 to
make it deterministic). But any change in the repository (e.g., somebody
else pushing, even to a ref you are not fetching) can cause unexpected
changes in the bytes.

-Peff

  reply	other threads:[~2015-02-17  0:56 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-02-16 13:16 Multi-threaded 'git clone' Koosha Khajehmoogahi
2015-02-16 13:31 ` David Lang
2015-02-16 15:03   ` Jeff King
2015-02-16 15:31     ` David Lang
2015-02-16 15:47       ` Jeff King
2015-02-16 18:43         ` Junio C Hamano
2015-02-17  3:16           ` Shawn Pearce
2015-02-16 23:16         ` Duy Nguyen
2015-02-17  0:56           ` Jeff King [this message]
  -- strict thread matches above, loose matches on Subject: below --
2015-02-17  5:20 Martin Fick
2015-02-17 23:32 ` Junio C Hamano
2015-02-18  3:14   ` Junio C Hamano

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