Date: Thu, 27 Apr 2000 09:26:05 -0600 From: Steve Passe <smp@csn.net> To: djb@ifa.au.dk Cc: Alfred Perlstein <bright@wintelcom.net>, freebsd-smp@FreeBSD.ORG Subject: Re: hlt instructions and temperature issues Message-ID: <200004271526.JAA24484@Ilsa.StevesCafe.com> In-Reply-To: Your message of "Thu, 27 Apr 2000 16:38:51 %2B0200." <20000427163851.A8149@relativity.student.utwente.nl>
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Hi, switch.s: ENTRY(default_halt) sti #ifndef SMP hlt /* XXX: until a wakeup IPI */ #endif ret I think the reason we don't hlt is that it is problematic to get the CPU running again without an INT to wake it up. So the scheduler has a process for it, but its not given a chance to run it as the CPU is hlt'd. As the comment suggests a wakeup IPI (inter-processor INT) could wake it, but the more complicated code is that which hands off the process from the signaling CPU to the recently woken CPU. -- Steve Passe | powered by smp@csn.net | Symmetric MultiProcessor FreeBSD To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-smp" in the body of the message
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