Re: gitk: avoid obscene memory consumption

From: Paul Mackerras <paulus@ozlabs.org>
Date: Nov 5, 2016, 11:08 UTC
Message-ID: <20161105110845.GA4039@fergus.ozlabs.ibm.com>
In-Reply-To: <CAGZ79kbavzGJ2sAcz5heg+BO+tZ=TgtrhxMH1-kqeJUpNNavyw@mail.gmail.com>

On Fri, Nov 04, 2016 at 03:45:09PM -0700, Stefan Beller wrote:

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> On Fri, Nov 4, 2016 at 12:49 PM, Markus Hitter <mah@jump-ing.de> wrote:
> >
> > Hello all,
> 
> +cc Paul Mackeras, who maintains gitk.

Thanks.

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> >
> > after Gitk brought my shabby development machine (Core2Duo, 4 GB RAM, Ubuntu 16.10, no swap to save the SSD) to its knees once more than I'm comfortable with, I decided to investigate this issue.
> >
> > Result of this investigation is, my Git repo has a commit with a diff of some 365'000 lines and Gitk tries to display all of them, consuming more than 1.5 GB of memory.
> >
> > The solution is to cut off diffs at 50'000 lines for the display. This consumes about 350 MB RAM, still a lot. These first 50'000 lines are shown, followed by a copyable message on how to view the full diff on the command line. Diffs shorter than this limit are displayed as before.

That sounds reasonable.

> 
> Bikeshedding: I'd argue to even lower the number to 5-10k lines.

I could go with 10k.

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> 
> >
> > To test the waters whether such a change is welcome, here's the patch as I currently use it. If this patch makes sense I'll happily apply change requests and bring it more in line with Git's patch submission expectations.
> 
> I have never contributed to gitk myself,
> which is hosted at git://ozlabs.org/~paulus/gitk
> though I'd expect these guide lines would roughly apply:
> https://github.com/git/git/blob/master/Documentation/SubmittingPatches

Paul.