From: Jeff Epler <jepler@unpythonic.net>
To: verrodj@uymail.com
Cc: linux-rt-users@vger.kernel.org
Subject: Re: system() instruction creates latency peaks
Date: Tue, 23 Oct 2018 16:48:12 -0500 [thread overview]
Message-ID: <20181023214812.3sqxq7w7xtnh6b2h@unpythonic.net> (raw)
In-Reply-To: <trinity-d772b31d-ea20-4c6d-92d9-387f0952bf76-1540308456962@3c-app-mailcom-lxa13>
Hi, I have experienced similar symptoms in realtime programs (LinuxCNC).
We have a control thread which sometimes does operations like system(),
and one or more realtime threads.
There, we changed from using system() to using posix_spawn and it
appears to have resolved the problem.
However, I don't have any explanation as to why this is the case. On
the specific version of glibc I have, posix_spawn uses vfork and system
uses clone; other syscalls like rt_sigaction are taken in the system
case but not the posix_spawn case.
Jeff
next parent reply other threads:[~2018-10-24 6:40 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <trinity-d772b31d-ea20-4c6d-92d9-387f0952bf76-1540308456962@3c-app-mailcom-lxa13>
2018-10-23 21:48 ` Jeff Epler [this message]
2018-11-08 9:53 ` system() instruction creates latency peaks Sebastian Andrzej Siewior
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