Re: [PATCH] travis-ci: run previously failed tests first, then slowest to fastest

From: Lars Schneider <larsxschneider@gmail.com>
Date: Jan 20, 2016, 09:22 UTC
Message-ID: <DBA834D2-BFC9-4A2F-94D9-A1D0D60377BD@gmail.com>
In-Reply-To: <xmqqfuxt6n00.fsf@gitster.mtv.corp.google.com>

On 20 Jan 2016, at 02:46, Junio C Hamano <gitster@pobox.com> wrote:

Show 25 quoted lines

> Mike Hommey <mh@glandium.org> writes:
> 
>> On Tue, Jan 19, 2016 at 03:00:52PM -0800, Junio C Hamano wrote:
>> 
>>> I think 3 comes from this:
>>> 
>>>  http://thread.gmane.org/gmane.comp.version-control.git/279348/focus=279674
>> 
>> Having recently looked into this, the relevant travis-ci documentation
>> is:
>> https://docs.travis-ci.com/user/ci-environment/
>> 
>> which says all environments have 2 cores, so you won't get much from
>> anything higher than -j3.
>> 
>> The following document also says something slightly different:
>> https://docs.travis-ci.com/user/speeding-up-the-build#Parallelizing-your-build-on-one-VM
>> 
>> "Travis CI VMs run on 1.5 virtual cores."
> 
> Yup, that 1.5 was already mentioned in the earlier thread, but many
> tests are mostly I/O bound, so 1.5 (or 2 for that matter) does not
> mean we should not go higher than -j2 or -j3.  What I meant was that
> the 3 comes from the old discussion "let's be nice to those who
> offer this to us for free".

I tested different settings and found that running prove with "-j5" seems to be the fastest option for the Travis CI machines. However, I also noticed that I got more test failures with higher parallelism (Dscho reported similar observations [1]).

Especially t0025-crlf-auto.sh failed multiple times ([2], [3]) on the OS X builds when I increase the parallelism:

not ok 4 - text=true causes a CRLF file to be normalized not ok 9 - text=auto, autocrlf=true _does_ normalize CRLF files

Anyone an idea why that might be the case?

Thanks, Lars

[1] http://article.gmane.org/gmane.comp.version-control.git/279660 [2] https://travis-ci.org/larsxschneider/git/jobs/103461538 [3] https://travis-ci.org/larsxschneider/git/jobs/103461458