Date: Sun, 28 Nov 1999 16:00:42 -0800 (PST) From: Julian Elischer <julian@whistle.com> To: peter.jeremy@alcatel.com.au Cc: freebsd-arch@freebsd.org Subject: Re: Which is the truth? (sycalls and traps) (fwd) Message-ID: <Pine.BSF.4.10.9911281554080.544-100000@current1.whistle.com> In-Reply-To: <99Nov29.103530est.40344@border.alcanet.com.au>
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On Mon, 29 Nov 1999, Peter Jeremy wrote: > On 1999-Nov-29 09:28:00 +1100, Julian Elischer wrote: > >(If the UTS is running then we just block the entire process) > > This could easily become a bottleneck on a large SMP system. I don't > believe the kernel scheduler should need to obtain an SMP lock for its > entire execution. Requiring this for a UTS sounds like a performance > hit. > If the Scheduler itself had a pagefault, the last thing you want to do is make an upcall to the scheduler! Since the schedular is constantly active this would probably only happen during startup. Though in scheduling a long asleep thread, it's stack may be out on swap. You'd need to work out a way of 'pre-faulting' in the thread's context so that the scheduler didn't block trying to load it. or at least scheduling it in a way that allowed the fault to not be charged against the scheduler, but rather against the thread. The second may actually not be too hard. Julian > Peter > To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message
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