Date: Wed, 25 May 2011 09:30:08 -0700 From: Garrett Cooper <yanegomi@gmail.com> To: Andriy Gapon <avg@freebsd.org> Cc: Attilio Rao <attilio@freebsd.org>, "freebsd-current@freebsd.org" <freebsd-current@freebsd.org>, "freebsd-arch@freebsd.org" <freebsd-arch@freebsd.org> Subject: Re: [rfc] remove hlt_cpus et al sysctls and related code Message-ID: <BANLkTin%2B1WkRWZomE7NJgaHagBBrwvT_Sw@mail.gmail.com> In-Reply-To: <4DDD2B34.5070702@FreeBSD.org> References: <4DD3F662.9040603@FreeBSD.org> <BANLkTikOTe9ut3GFx0bhOernKandRGLhPg@mail.gmail.com> <BANLkTinVGrLoAOS_ZQ1YVB_Fw1cvf5kHyA@mail.gmail.com> <BBCD9D8C-FCAF-4DE3-9F66-4B65AAABE67B@gmail.com> <BANLkTikMZ_xs4WCJVJG4oHe3rOKU8rqfVw@mail.gmail.com> <4DD54C18.8050305@FreeBSD.org> <4DDA8B2A.6010500@FreeBSD.org> <4DDD2B34.5070702@FreeBSD.org>
next in thread | previous in thread | raw e-mail | index | archive | help
On Wed, May 25, 2011 at 9:15 AM, Andriy Gapon <avg@freebsd.org> wrote: > on 23/05/2011 19:28 Andriy Gapon said the following: >> I propose the following path for moving forward. >> - use hint.lapic.X.disabled to disable individual CPUs by their APIC ID >> - use machdep.hyperthreading_allowed tunable to disable second logical C= PU on each >> real core >> >> The above should already work as expected. =A0One thing is that currentl= y we have >> handling of machdep.hyperthreading_allowed tunable under SCHED_ULE. =A0I= plan to >> make it unconditional. >> >> Things to remove: >> - all the related sysctls for dynamic onlining/offlining >> - machdep.hlt_logical_cpus tunable (it duplicates hint.lapic.X.disabled) >> >> It's possible to keep machdep.hlt_logical_cpus and just add some code to= convert >> hlt_logical_cpus mask to a set of individual hint.lapic.X.disabled, but = I don't >> see very much value in that. =A0But if there is a good reason to keep th= at tunable, >> I am prepared to jump through this hoop. >> >> If no one objects to this proposal, I will provide a patch soon. > > The patch is here: > http://people.freebsd.org/~avg/cpu-offline-sysctl.diff > It should implement the strategy described above. > > I have mp_watchdog alone for now. =A0It seems to have the same issues wit= h respect > to dynamic CPU state change. =A0Besides its compilation is disabled when = SCHED_ULE > is enabled. =A0mp_watchdog is a nice idea, but I wonder if anyone actuall= y uses it > (with success). I'll have to test out the patch, but at first glance it seems ok (at least the machdep.hyperthreading_allowed changes which $WORK depends upon). Thanks! -Garrett
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?BANLkTin%2B1WkRWZomE7NJgaHagBBrwvT_Sw>