Re: [Fwd: Re: execv bug???]
Re: [Fwd: Re: execv bug???]
- Subject: Re: [Fwd: Re: execv bug???]
- From: email@hidden (Peter Seebach)
- Date: Sun, 27 Jan 2008 19:15:44 -0600
In message <email@hidden>, Jonas Maebe wr
ites:
>That's more or less true for Linux, but not for Mac OS X at least up
>till 10.4.x (I haven't benchmarked on 10.5 yet). Compiling our
>compiler with itself, which involves about 173 (v)fork+execs from a
>single compiler run to assemble&link all the files, is 20% to 25%
>slower with fork instead of vfork on a G4, and 35% to 40% on a G5 (32
>bit processes in both cases) on 10.4.x. And for clarity: this is
>relative to the entire time needed for compiling+assembling+linking
>everything (on the G5: 24 vs 15 seconds), not some academic mbench-
>like speed difference between the fork and vforks.
Yes. It does make a difference, but even so, the API is deprecated,
so even if this hurts performance a bit, it's still probably best to
avoid it whenever possible.
>The modern alternative is obviously posix_spawn, but we cannot use
>that since we still support 10.3.x (it even probably even still works
>on 10.1 and 10.2 as well, but I don't test those anymore).
True.
That said, the code in question is a bug according to the documented semantics
of vfork on OS X.
-s
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