GNU bug report logs - #66288
29.1; Performance regression using pipe for subprocess

Previous Next

Full log

Message #98 received at 66288 <at> debbugs.gnu.org (full text, mbox):

From: Paul Eggert <eggert <at> cs.ucla.edu>
To: Eli Zaretskii <eliz <at> gnu.org>, Chris Hanson <cph <at> chris-hanson.org>
Cc: gerd.moellmann <at> gmail.com, dmitry <at> gutov.dev, gregory <at> heytings.org,
 66288 <at> debbugs.gnu.org
Subject: Re: bug#66288: 29.1; Performance regression using pipe for subprocess
Date: Wed, 4 Oct 2023 15:49:00 -0700

On 10/3/23 23:52, Eli Zaretskii wrote:


> +#if defined(GNU_LINUX) && defined(F_SETPIPE_SZ) && defined(F_GETPIPE_SZ)

A small point: no need to check whether GNU_LINUX is defined; any system 
having these two Linux macros should be Linux-compatible.

> +      /* If they requested larger reads than the default system pipe
> +         capacity, enlarge the capacity to match the request.  */
> +      if (read_process_output_max > fcntl (inchannel, F_GETPIPE_SZ))
> +	{
> +	  int readmax = clip_to_bounds (1, read_process_output_max. INT_MAX);

"." -> "," of course.

> +	  fcntl (inchannel, F_SETPIPE_SZ, readmax);

This call can fail if you aren't root and you exceed the system limit in 
/proc/sys/fs/pipe-max-size. So I suggest that if this fnctl fails with 
EPERM, trying it again after clipping to that limit.

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.