From owner-freebsd-hackers Sun Dec 5 3:34:15 1999 Delivered-To: freebsd-hackers@freebsd.org Received: from ns.skylink.it (ns.skylink.it [194.177.113.1]) by hub.freebsd.org (Postfix) with ESMTP id 1910915063 for ; Sun, 5 Dec 1999 03:33:59 -0800 (PST) (envelope-from hibma@skylink.it) Received: from skylink.it (va-160.skylink.it [194.185.55.160]) by ns.skylink.it (8.9.1/8.8.8) with ESMTP id MAA04590; Sun, 5 Dec 1999 12:33:07 +0100 Received: from localhost (localhost [127.0.0.1]) by skylink.it (8.9.3/8.9.3) with ESMTP id KAA01879; Sun, 5 Dec 1999 10:55:32 +0100 (CET) (envelope-from hibma@skylink.it) Date: Sun, 5 Dec 1999 10:55:32 +0100 (CET) From: Nick Hibma X-Sender: n_hibma@henny.jrc.it Reply-To: Nick Hibma To: Doug Barton Cc: freebsd-hackers@FreeBSD.org Subject: Re: Basic question about threads and SMP In-Reply-To: Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG Being multi-threaded has almost nothing to do with being multi-processor. Multi-threading means that your application has multiple threads of execution that are able to run simultaneously. The multi-processing capability of your box means that 2 threads of execution, be it a process or a thread within a process, are executed _literally_ at the same time, and not in simulated concurrency like it happens on a UP box. Whether or not any application should be compiled with libc_r depends solely on the application itself. And, as you suggest, that is decided at build time. If applications support multi-threading they normally come with a Makefile using libc_r. Now, whether you want to multi-thread Apache is totally different issue ... Nick On Wed, 1 Dec 1999, Doug Barton wrote: > You know, a stray thought just occured to me, which hopefully > won't sound to silly to people who know about this stuff. :) If I have an > SMP box (using -Current specifically) do I want to be compiling things > with -lc_r? I'm thinking specifically of mission critical things like > apache, but in general will other ports and such take advantage of > libc_r if they are compiled with it, or would a program that _can_ take > advantage of it already have that built in, say into autoconf or some > such? What about other parts of the base system? I'm assuming that the > kernel is covered by virtue of the fact that I've enabled the SMP options, > yes? > > I'm trying to learn more about SMP, threads, and such like in > general. The recent conversations about those topics on the lists have > been very educational. I'm still wading through them, but I appreciate > being able to sit on the sidelines and glean bits here and there. > > Thanks, > > Doug > -- > "Welcome to the desert of the real." > > - Laurence Fishburne as Morpheus, "The Matrix" > > > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-hackers" in the body of the message > -- hibma@skylink.it n_hibma@freebsd.org USB project http://www.etla.net/~n_hibma/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message