From: Matthieu Moy <Matthieu.Moy@grenoble-inp.fr>
To: Junio C Hamano <gitster@pobox.com>
Cc: Johannes Schindelin <Johannes.Schindelin@gmx.de>, git@vger.kernel.org
Subject: Re: Drastic jump in the time required for the test suite
Date: Thu, 20 Oct 2016 19:13:47 +0200 [thread overview]
Message-ID: <vpqinsnndtg.fsf@anie.imag.fr> (raw)
In-Reply-To: <xmqqmvhzhu6f.fsf@gitster.mtv.corp.google.com> (Junio C. Hamano's message of "Thu, 20 Oct 2016 09:16:56 -0700")
Junio C Hamano <gitster@pobox.com> writes:
> Are you proposing to replace the tests written as shell scripts with
> scripts in another language or framework that run equivalent
> sequences of git commands that is as portable as, if not more,
> Bourne shell?
The language (/bin/sh) is probably not the biggest issue. The way we use
it may be.
I don't have benchmark to tell what slows down the testsuite, but for
example we often write
cat >expected <<EOF &&
content
EOF
git foo >actual &&
test_cmp expected actual
We create 2 files, fork one 'cat' and one 'diff'. Now, suppose we can
write instead
test_check_output git foo <<EOF
content
EOF
where test_check_output would be a compiled program running "git foo"
with popen(), reading the expected output on stdin, and comparing both
(and possibly creating files and forking 'diff', but only on the error
path). That would reduce the overhead of test a lot: on fork+exec to
create the "test_check_output" process + plain string comparison.
Obviously, I don't expect this change to drastically reduce the time
(Peff's numbers seem to suggest that there's not so much to gain), but
maybe getting a few C helpers and "optimized" idioms in our testsuite
could lead to measurable improvements.
--
Matthieu Moy
http://www-verimag.imag.fr/~moy/
next prev parent reply other threads:[~2016-10-20 17:14 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-19 9:18 Drastic jump in the time required for the test suite Johannes Schindelin
2016-10-19 17:32 ` Junio C Hamano
2016-10-19 20:56 ` Jeff King
2016-10-20 10:50 ` Johannes Schindelin
2016-10-20 11:39 ` Jeff King
2016-10-20 19:54 ` Stefan Beller
2016-10-20 21:38 ` Jeff King
2016-10-20 21:53 ` Stefan Beller
2016-10-20 21:57 ` Jeff King
2016-10-20 21:56 ` Jeff King
2016-10-21 5:27 ` Johannes Sixt
2016-10-21 8:24 ` Jeff King
2016-10-20 10:17 ` Johannes Schindelin
2016-10-20 12:31 ` Jeff King
2016-10-20 16:30 ` Stefan Beller
2016-10-20 21:00 ` Jeff King
2016-10-20 23:20 ` Jeff King
2016-10-20 20:38 ` Johannes Sixt
2016-10-20 21:03 ` Jeff King
2016-10-20 20:40 ` Dennis Kaarsemaker
2016-10-21 11:03 ` Duy Nguyen
2016-10-20 16:16 ` Junio C Hamano
2016-10-20 17:13 ` Matthieu Moy [this message]
2016-10-20 11:02 ` Duy Nguyen
2016-10-20 16:40 ` René Scharfe
2016-10-21 10:59 ` Duy Nguyen
2016-10-21 20:28 ` René Scharfe
2016-10-21 13:10 ` Matthieu Moy
2016-10-21 19:57 ` René Scharfe
2016-10-27 20:41 ` Eric Wong
2016-10-28 6:38 ` Duy Nguyen
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