Date: Tue, 2 May 2000 18:32:18 +0000 (GMT) From: Terry Lambert <tlambert@primenet.com> To: djb@ifa.au.dk Cc: smp@csn.net (Steve Passe), kpielorz@tdx.co.uk (Karl Pielorz), smp@FreeBSD.ORG Subject: Re: hlt instructions and temperature issues Message-ID: <200005021832.LAA21819@usr01.primenet.com> In-Reply-To: <20000501161626.A4317@relativity.student.utwente.nl> from "Dave Boers" at May 01, 2000 04:16:26 PM
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[ ... sysctl ... ] > This looks like an excellent proposal. Does anyone have comments, or could > someone with experience" in this area provide a patch? As an experiment to convince people, this is OK. As a permanent change, it's wrong. Without handling the stalling case, the code is incorrect, and _will_ result in poorer performance on the first idle/resource wait. As an alternative, I suggest someone run multiple programs that can get I/O bound, and then swap the vector out from under the processors, thus enabling the hlt. This should stall all but one processor, as handling the interrupt requires the BGL, and the BGL will be held by a single CPU most of the time as a result of an I/O bound program. Basically, this means that everything but one CPU will hlt, and that it will hlt too, with only one CPU waking up when an interrupt happens on the I/O completion. 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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