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Re: Inefficient stat-ing of files?

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From:
Craig A. Berry
Date:
June 29, 2016 19:51
Subject:
Re: Inefficient stat-ing of files?
Message ID:
CA+vYcVyKS0TysA0WmZNk-bWCcfgOTpxE=Q7Sd76s9N4+=Cc_Sw@mail.gmail.com
On Wed, Jun 29, 2016 at 2:24 PM, Sawyer X <xsawyerx@gmail.com> wrote:
>
> On 06/24/2016 07:05 PM, Zefram wrote:
>> Craig A. Berry wrote:
>>
>>> It looks like we could cut the number of stat calls when loading
>>> modules in about half by removing the checks for .pmc files.
>> That's a viable suggestion.  It would be a visible behaviour change,
>> not a pure optimisation, but likely to be quite acceptable.
>
> Perhaps we should revisit the idea?

As bulk88 pointed out up-thread, you can already do this by
configuring with -DPERL_DISABLE_PMC, so the question would be whether
that became the default.  As Dave pointed out, there is no measurable
benefit to skipping .pmc lookups, at least on Linux.  On systems with
more expensive stat calls, it's possible it could make a difference,
in which case we'd need to evaluate the risk of changing the default
behavior.  Somebody somewhere has probably used it as a generic
override mechanism rather than for its intended purpose.

> Having .pmc files that work could be a much greater optimization...

My impression is that's just not gonna happen, but I'd be happy to be
proven wrong.

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