Date: Mon, 7 Dec 1998 22:19:57 +0000 (GMT) From: Terry Lambert <tlambert@primenet.com> To: marcelk@stack.nl (Marcel van Kervinck) Cc: smp@FreeBSD.ORG Subject: Re: Pthreads and SMP Message-ID: <199812072219.PAA16916@usr06.primenet.com> In-Reply-To: <19981206172549.A11335@unox.student.tue.nl> from "Marcel van Kervinck" at Dec 6, 98 05:25:49 pm
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> Perhaps I've missed something obvious But: it seems to me that a process > that uses multiple threads doesn't spread them over more processors? That is correct. The threads are user space threads, which execute in a single process context. > I tried on a dual PII, running fbsd 3.0, and a program that simply did > a few pthread_create() calls. There are L1 and L2 cache coherency issues that impact bus based arbitration and invalidation bottlenecks, there are scheduler issues (both user and kernel space), there are stack issues, there are address space issues, memory model issues, and a slew more issues. These problems are not as trivially solvable, as the poor Linux and SVR4 kernel threading implementations, or the EGCS thread support assumptions would have you believe. Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-smp" in the body of the message
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