On Sat, Sep 15, 2001 at 06:06:10PM -0400, Garance A Drosihn wrote:
> At 12:38 PM -0400 9/15/01, Mike Tancsa wrote:
> >Should a parallel build always work ? I was just trying to stress
> >a new series of MB we are evaluating and to my suprise, -j4 works,
> >but not -j8
>
> Well, in a philosophical sense, yes it "should" always work. Bugs
> creep into the process from time-to-time. I can not say that I
> know how to pin down such problems when they occur. I do know
> that earlier this year I had some problem I was checking, and as
> a tangent to that problem I did several fresh 'make buildworld's,
> going from -j2 to -j10 on my dual 650-MHz pentium machine. I then
> did md5 comparisons of the resulting obj-tree results, and they all
> came out the same. Of course, I wasn't getting any errors at build
> time, either.
In my experience with a 2-CPU box, the problems with -j 5 or
bigger are exclusively with module (or include file, etc.) A not
being built by the time that process B needs it to complete a
compile or link or whatever. These failures, in general, don't
recur if the make is rerun from the failure point -- even with
-j 8 or more. I frequently run with -j 16 when I'm doing kernel
builds and buildworlds, and I haven't had any of those fail in a
longish time.
--
Mike Andrews
[EMAIL PROTECTED]
Tired old sysadmin since 1964
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