Date: Mon, 28 Apr 1997 10:44:21 -0700 (MST) From: Terry Lambert <terry@lambert.org> To: chuckr@mat.net (Chuck Robey) Cc: black@zen.cypher.net, FreeBSD-SMP@FreeBSD.org Subject: Re: SMP Message-ID: <199704281744.KAA02167@phaeton.artisoft.com> In-Reply-To: <Pine.BSF.3.91.970427235620.22821K-100000@Journey2.mat.net> from "Chuck Robey" at Apr 27, 97 11:58:37 pm
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> I'm confused, then. If there's only one kernel, then only one cpu can > run it, so only one cpu can field the system calls. If both cpu's can > field system calls, then unless they contact the other one to get the > work done, then there must be two copies of the kernel ruinning, right? > > I'm probably misunderstanding something. Maybe you meant only one piece > of software called "kernel" but two cpus running it? The lock is acquired at system call time. Only one CPU can acquire the lock at a time, so the kernel is not reentered. But any CPU may acquire the lock. Effectively, there is a single kernel which can be run by only one CPU at a time. Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers.
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