GNU bug report logs - #23848
sed not using unlocked_stdio

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Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Tristan Verniquet <tverniquet <at> gmail.com>
To: bug-sed <at> gnu.org
Subject: sed not using unlocked_stdio
Date: Sat, 25 Jun 2016 22:10:13 +1000

[Message part 1 (text/plain, inline)]

sed 4.2.2

Most reading and writing is done in utils.c, but this does not include
sed.h or the "unlocked-io.h" header.

ltrace sed '' < <(seq 1 100)

Shows lots of calls to the locked system calls.

Adding include "sed.h" in utils.c and recompling and re-running ltrace
shows the _unlocked() variants being used.

This improves the performance when reading the output of seq 1 1e8 from 9.5
seconds to 6.4 seconds. ie:

time sed '' < seq.1e8 >/dev/null

(on ubuntu 16.04 with skylake processor)

[Message part 2 (text/html, inline)]

Message #8 received at 23848 <at> debbugs.gnu.org (full text, mbox):

From: Assaf Gordon <assafgordon <at> gmail.com>
To: Tristan Verniquet <tverniquet <at> gmail.com>
Cc: 23848 <at> debbugs.gnu.org
Subject: Re: bug#23848: sed not using unlocked_stdio
Date: Sat, 25 Jun 2016 22:14:30 -0400

[Message part 1 (text/plain, inline)]

Hello Tristan,

> On Jun 25, 2016, at 08:10, Tristan Verniquet <tverniquet <at> gmail.com> wrote:
> Most reading and writing is done in utils.c, but this does not include
> sed.h or the "unlocked-io.h" header.

Thank you for the report.

The attached patch addresses the issue.
I see similar speed-ups on my system.

As sed is in the midst of several code changes, this patch is not yet pushed in to the git repository,
but I'm confident it will included in the upcoming sed-4.3 release.
I'll leave this bug 'open' until the patch is pushed.

regards,
 - assaf

[0001-sed-use-unlocked-io.patch (application/octet-stream, attachment)]

Message #11 received at 23848 <at> debbugs.gnu.org (full text, mbox):

From: Jim Meyering <jim <at> meyering.net>
To: Tristan Verniquet <tverniquet <at> gmail.com>
Cc: 23848 <at> debbugs.gnu.org
Subject: Re: bug#23848: sed not using unlocked_stdio
Date: Sat, 25 Jun 2016 22:29:31 -0600

On Sat, Jun 25, 2016 at 6:10 AM, Tristan Verniquet <tverniquet <at> gmail.com> wrote:
> sed 4.2.2
>
> Most reading and writing is done in utils.c, but this does not include
> sed.h or the "unlocked-io.h" header.
>
> ltrace sed '' < <(seq 1 100)
>
> Shows lots of calls to the locked system calls.
>
> Adding include "sed.h" in utils.c and recompling and re-running ltrace
> shows the _unlocked() variants being used.
>
> This improves the performance when reading the output of seq 1 1e8 from 9.5
> seconds to 6.4 seconds. ie:
>
> time sed '' < seq.1e8 >/dev/null

Thanks for the report and the suggested fix. That sounds right, indeed.

Message #14 received at 23848 <at> debbugs.gnu.org (full text, mbox):

From: Assaf Gordon <assafgordon <at> gmail.com>
To: Tristan Verniquet <tverniquet <at> gmail.com>
Cc: 23848 <at> debbugs.gnu.org
Subject: Re: bug#23848: sed not using unlocked_stdio
Date: Wed, 29 Jun 2016 00:56:40 -0400

close 23848
thanks

Hello Tristan,

The unlocked-io change has been pushed in your name, here:
  http://git.savannah.gnu.org/cgit/sed.git/commit/?id=6ad4acfbd5f1f56e6a93db476f29d299a698150e


I'm thus marking this item as 'closed'.

regards,
 - assaf

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