Date: Tue, 22 Jan 2002 14:20:22 -0600 From: mikea <mikea@mikea.ath.cx> To: Stephen Montgomery-Smith <stephen@math.missouri.edu> Cc: freebsd-stable@FreeBSD.ORG Subject: Re: Error in make buildworld Message-ID: <20020122142022.B6717@mikea.ath.cx> In-Reply-To: <3C4DC7B6.B6C55696@math.missouri.edu>; from stephen@math.missouri.edu on Tue, Jan 22, 2002 at 02:12:38PM -0600 References: <3C4D86A0.1BDE2840@math.missouri.edu> <20020122094857.A5407@mikea.ath.cx> <3C4DC7B6.B6C55696@math.missouri.edu>
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On Tue, Jan 22, 2002 at 02:12:38PM -0600, Stephen Montgomery-Smith wrote: > mikea wrote: > > This is a known difficulty with multiple make threads. Note that > > I do _NOT_ call it a problem. It is caused by a thread that > > needs <foo> getting to the part that expects <foo> to have been > > built before the thread that actually builds <foo> gets to the > > build-foo code. I have found that I frequently can reissue the > > same command and <foo> will get built before it is required by > > something in another thread, and the make will run to completion > > the second time. > But shouldn't the make wait until the first thread finishes before > starting the dependent thread? > > (But I guess if the computer is really fast, it doesn't matter if you > don't have -j4. make buildworld takes 45 minutes on the "fast" > machine.) I haven't noticed that thread synchronization (if make does any) is particularly good for -j 4 or bigger. I have seen that -j 4 is safe on my 2xPIII-866 system, and that -j 8 or larger will fail from time to time because of dependencies not being satisfied. I'm running 4.5-RC1, with UDMA-66 disks and 1GB of RAM, and it runs like a scalded ape, but sometimes make just falls over dead because it needs <foo> and <foo>'s not built yet. Maybe someone with more knowledge can discuss thread synch issues in make, or provide some URLs. I'd like to know more. -- Mike Andrews mikea@mikea.ath.cx Tired old sysadmin since 1964 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
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