Date: Mon, 19 Oct 2009 16:05:41 +0100 (BST) From: Robert Watson <rwatson@FreeBSD.org> To: Taku YAMAMOTO <taku@tackymt.homeip.net> Cc: freebsd-current@freebsd.org Subject: Re: softclock swis not bound to specific cpu Message-ID: <alpine.BSF.2.00.0910191604250.48055@fledge.watson.org> In-Reply-To: <20091018202407.656c3863.taku@tackymt.homeip.net> References: <20091018202407.656c3863.taku@tackymt.homeip.net>
next in thread | previous in thread | raw e-mail | index | archive | help
On Sun, 18 Oct 2009, Taku YAMAMOTO wrote: > I noticed that the softclock threads didn't seem to be bound to any cpu. > > I'm not sure whether it's the Right Thing (TM) to bind them to the > corresponding cpus though: it might be good to give the scheduler a chance > to rebalance callouts. > > I'm about to test the modification like the attached diff. Comments are > welcome. Yes, I think the intent is that they have a "soft" affinity to the CPU where the lapic timer is firing, but not a hard binding, allowing them to migrate if required. It would be interesting to measure how effective that soft affinity is in practice under various loads -- presumably the goal would be for the softclock thread to migrate if a higher (lower) priority thread is hogging the CPU. Robert N M Watson Computer Laboratory University of Cambridge
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?alpine.BSF.2.00.0910191604250.48055>