From owner-freebsd-stable Sat Sep 15 15:23:22 2001 Delivered-To: freebsd-stable@freebsd.org Received: from mikea.ath.cx (okc-65-26-223-53.mmcable.com [65.26.223.53]) by hub.freebsd.org (Postfix) with ESMTP id 1A1C437B405 for ; Sat, 15 Sep 2001 15:23:13 -0700 (PDT) Received: (from mikea@localhost) by mikea.ath.cx (8.11.6/8.11.1) id f8FMN8K73181 for stable@FreeBSD.ORG; Sat, 15 Sep 2001 17:23:08 -0500 (CDT) (envelope-from mikea) Date: Sat, 15 Sep 2001 17:23:07 -0500 From: mikea To: stable@FreeBSD.ORG Subject: Re: make -j4 vs -j8... 4 works, but 8 does not Message-ID: <20010915172307.A73155@mikea.ath.cx> References: <5.1.0.14.0.20010915123606.035fcc18@192.168.0.12> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: ; from drosih@rpi.edu on Sat, Sep 15, 2001 at 06:06:10PM -0400 Sender: owner-freebsd-stable@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG 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 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