From: Mark Grosberg <mark@nolab.conman.org>
To: dean gaudet <dean-list-linux-kernel@arctic.org>
Cc: "Måns Rullgård" <mru@users.sourceforge.net>,
"Larry McVoy" <lm@bitmover.com>,
linux-kernel@vger.kernel.org
Subject: Re: [RFD] Combined fork-exec syscall.
Date: Sun, 27 Apr 2003 21:59:39 -0400 (EDT) [thread overview]
Message-ID: <Pine.BSO.4.44.0304272154080.23296-100000@kwalitee.nolab.conman.org> (raw)
In-Reply-To: <Pine.LNX.4.53.0304271843010.8792@twinlark.arctic.org>
On Sun, 27 Apr 2003, dean gaudet wrote:
> the only time fork-exec is inefficient, given the existence of vfork, is
> when you need to fork a process which has a lot of fd. and by "a lot" i
> mean thousands.
Depends at what level of optimization you are talking about. I consider a
syscall an expensive operation. The transition from user to kernel mode,
the setup and retrieval of parameters all cost (and some architectures are
worse at it than i386).
> but even this has a potential work-around using procfs -- use clone() to
> get the vfork semantics without also copying the fd array. then open
> /proc/$ppid/fd/N for any file descriptors you want opened in the forked
> process.
That is still quite a few syscalls (and some path walking for each file
descriptor)... I was proposing to get around the syscall overhead which
on large multi-user systems (or webservers running lots of CGI) could be
significant.
Honestly, I'm not sure if it is necessary either. But I can think of a few
advantages (and people on the list have thought of more)... How do
MMU-less archs spawn processes? Do they always use vfork()?
L8r,
Mark G.
next prev parent reply other threads:[~2003-04-28 1:47 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-04-28 0:57 [RFD] Combined fork-exec syscall Mark Grosberg
2003-04-28 0:59 ` Larry McVoy
2003-04-28 1:16 ` Mark Grosberg
2003-04-28 1:36 ` Måns Rullgård
2003-04-28 1:45 ` Mark Grosberg
2003-04-28 1:49 ` dean gaudet
2003-04-28 1:59 ` Mark Grosberg [this message]
2003-04-28 2:27 ` Miles Bader
2003-04-28 19:07 ` dean gaudet
2003-05-01 13:14 ` Jakob Oestergaard
2003-04-28 1:17 ` Davide Libenzi
2003-04-28 1:28 ` Mark Grosberg
2003-04-29 2:01 ` Rafael Costa dos Santos
2003-04-28 1:41 ` Ulrich Drepper
2003-04-28 1:49 ` Mark Grosberg
2003-04-28 2:19 ` Ulrich Drepper
2003-04-28 6:59 ` Kai Henningsen
2003-04-28 1:35 ` dean gaudet
2003-04-28 1:43 ` Mark Grosberg
2003-04-28 3:44 ` Mark Mielke
2003-04-28 5:16 ` Jamie Lokier
2003-04-28 2:38 ` Davide Libenzi
2003-04-28 2:09 ` Richard B. Johnson
2003-04-28 2:12 ` Mark Grosberg
2003-04-28 2:42 ` Werner Almesberger
2003-04-28 6:35 ` Mark Grosberg
2003-04-29 2:47 ` Rafael Santos
2003-04-28 3:20 ` Werner Almesberger
2003-04-28 13:00 ` Richard B. Johnson
2003-04-28 13:22 ` Andreas Schwab
2003-04-28 13:57 ` Richard B. Johnson
2003-04-28 13:57 ` Andreas Schwab
2003-04-28 14:16 ` Richard B. Johnson
2003-04-28 14:38 ` Valdis.Kletnieks
2003-04-28 14:56 ` Richard B. Johnson
2003-04-28 14:42 ` Andreas Schwab
2003-04-28 16:36 ` Mark Grosberg
2003-04-28 17:19 ` Davide Libenzi
2003-04-28 18:28 ` Craig Ruff
2003-05-06 2:48 ` Miles Bader
2003-04-29 18:50 ` Timothy Miller
2003-04-28 2:32 ` Werner Almesberger
2003-04-28 7:40 ` Mirar
2003-04-28 12:45 ` Matthias Andree
2003-04-29 1:05 ` Rafael Costa dos Santos
2003-04-28 1:19 ` Mark Grosberg
2003-04-29 1:29 ` Rafael Costa dos Santos
2003-04-28 3:03 Davide Libenzi
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