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Re: [Fwd: Re: execv bug???]
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Re: [Fwd: Re: execv bug???]


  • Subject: Re: [Fwd: Re: execv bug???]
  • From: Jonas Maebe <email@hidden>
  • Date: Mon, 28 Jan 2008 13:28:30 +0100


On 28 Jan 2008, at 02:15, Peter Seebach wrote:

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.

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.



Jonas _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (email@hidden) Help/Unsubscribe/Update your Subscription: This email sent to email@hidden
  • Follow-Ups:
    • Re: [Fwd: Re: execv bug???]
      • From: email@hidden (Peter Seebach)
    • Re: [Fwd: Re: execv bug???]
      • From: Dave Zarzycki <email@hidden>
References: 
 >Re: [Fwd: Re: execv bug???] (From: email@hidden (Peter Seebach))

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