Date: Mon, 21 Feb 2011 12:07:54 -0800 From: Garrett Cooper <gcooper@FreeBSD.org> To: Andriy Gapon <avg@freebsd.org> Cc: freebsd-hackers@freebsd.org, Steven Hartland <killing@multiplay.co.uk>, freebsd-stable@freebsd.org Subject: Re: machdep.hlt_cpus not safe with ULE? Message-ID: <AANLkTinmSpwW4-TcJDZAB8p1_%2BPOUhA06PjJeYUN-w=V@mail.gmail.com> In-Reply-To: <4D6292DD.8010704@freebsd.org> References: <8332E9240ECA403480B48D21FA3A8694@multiplay.co.uk> <4D6292DD.8010704@freebsd.org>
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On Mon, Feb 21, 2011 at 8:29 AM, Andriy Gapon <avg@freebsd.org> wrote: > on 19/02/2011 14:36 Steven Hartland said the following: >> I'm trying to debug a possibly failing CPU, so I thought it would >> be easy just disable the cores using machdep.hlt_cpus and see if >> we see the panic's we've been seeing. >> >> The problem is it seems ULE doesnt properly support machdep.hlt_cpus >> and still schedules processes onto the halted cpus which obviously >> causes problems. >> >> Can anyone confirm this behaviour? > > Yes, your observations are correct. > Please also see: http://www.freebsd.org/cgi/query-pr.cgi?pr=145385 > >> Should machdep.hlt_cpus and I assume >> the logical counterpart never be used with ULE? As a followup to this and based on discussions with other folks, the fact that it's using hlt to halt CPUs without rescheduling tasks / masking interrupts, etc is not good. So none of the *hlt* sysctls are really doing the right thing on x86. Thanks, -Garrett
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