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From: Jeff King <peff@peff.net>
To: Junio C Hamano <gitster@pobox.com>
Cc: Vicent Marti <tanoku@gmail.com>,
	Jonathan Nieder <jrnieder@gmail.com>,
	git@vger.kernel.org, Petr Onderka <gsvick@gmail.com>
Subject: Re: [RFC/PATCH 2/2] tests: scrub environment of GIT_* variables
Date: Tue, 15 Mar 2011 16:01:03 -0400	[thread overview]
Message-ID: <20110315200103.GA3953@sigill.intra.peff.net> (raw)
In-Reply-To: <7v4o74b8r5.fsf@alter.siamese.dyndns.org>

On Tue, Mar 15, 2011 at 10:20:46AM -0700, Junio C Hamano wrote:

> I am perfectly fine with the use of perl but do we know the "perl" binary
> found on $PATH (as opposed to $PERL_PATH) is good to use for this purpose?
> The features used in the scriptlet seem so bread-and-butter that I don't
> think it would make too much of a difference, but we may want to be
> consistent.

We already make the assumption elsewhere in the tests that perl in $PATH
is some minimal sane version (which probably means some version of perl5
in practice). This little script looks like it should run under any
perl5 to me.

> I personally think USE_LOOKUP outlived its usefulness. It was meant to be
> an easy way to experiment if the sha1_entry_pos() lookup gives better
> performance while looking up a pack entry, to choose one implementation
> and discard the other, but I don't think anybody actually did meaningful
> benchmarks to decide which one to keep.
> 
> Perhaps we should discard the codepath USE_LOOKUP turns on, which I
> suspect hasn't been exercised since v1.5.6 days by anybody. An obvious
> alternative is for somebody to try using USE_LOOKUP and see if it really
> gives a better performance with large packs (and if so, always use it and
> discard the other codepath).

Vicent asked me about it the other day with respect to doing something
similar in libgit2. I tried a few basic things and never ended up
getting any substantially different timing (or even page faults) between
the two strategies. Vicent, did you do any timings where it made a
difference?

-Peff

      reply	other threads:[~2011-03-15 20:01 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-03-15  6:49 [PATCH 0/3] tests: unsetting variables that influence the outcome Jonathan Nieder
2011-03-15  6:56 ` [PATCH 1/3] tests: protect against GIT_ATTR_NOGLOBAL from environment Jonathan Nieder
2011-03-15  6:56 ` [PATCH 2/3] tests: suppress global and system gitattributes Jonathan Nieder
2011-03-15  7:16   ` Jeff King
2011-03-15  9:02     ` [PATCH 1-2/3 v2 0/3] " Jonathan Nieder
2011-03-15  9:04       ` [PATCH 1/3] gitattributes: drop support for GIT_ATTR_NOGLOBAL Jonathan Nieder
2011-03-15  9:04       ` [PATCH 2/3] config: drop support for GIT_CONFIG_NOGLOBAL Jonathan Nieder
2011-03-15  9:05       ` [PATCH 3/3] tests: suppress system gitattributes Jonathan Nieder
2011-03-15  7:04 ` [PATCH 3/3] tests: scrub environment of GIT_* variables Jonathan Nieder
2011-03-15  7:37   ` Jeff King
2011-03-15 10:08     ` [RFC/PATCH 0/2] tests: stop hard-coding the list of GIT_* vars to scrub Jonathan Nieder
2011-03-15 10:09       ` [PATCH 1/2] tests: stop worrying about obsolete environment variables Jonathan Nieder
2011-03-15 10:10       ` [RFC/PATCH 2/2] tests: scrub environment of GIT_* variables Jonathan Nieder
2011-03-15 17:20         ` Junio C Hamano
2011-03-15 20:01           ` Jeff King [this message]

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