Re: [Fwd: Re: execv bug???]
Re: [Fwd: Re: execv bug???]
- Subject: Re: [Fwd: Re: execv bug???]
- From: Andrew Gallatin <email@hidden>
- Date: Mon, 28 Jan 2008 11:39:06 -0500 (EST)
Peter Seebach writes:
> In message <email@hidden>, Jonas Maebe wr
> ites:
> >If it only hurt performance a bit I would never have changed the code
> >from using fork (which is what we used on all other *nix ports) into
> >using vfork in the first place. But a 25% to 40% slowdown caused by
> >173 system calls in the process of compiling about 180 kloc is
> >astronomical in my view.
>
> It does seem unusually large, and I'd be interested in seeing what caused it.
There was an interesting fork/exec performance thread quite
a while back. (http://lists.apple.com/archives/darwin-kernel/2002/Sep/msg00060.html)
I see they've fixed the underlying problem in this particular thread
(which turned out to be that the fork/exec cost scaled poorly with
stack size), but shell scripts (expecially configure) remain painfully
slow compared to Linux or Solaris on the same hardware. Lmbench
still shows fork+exec taking roughly 5x-10x as long on MacOSX as
Linux on the same hardware.
Drew
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