From owner-freebsd-current@FreeBSD.ORG Fri May 9 21:05:28 2014 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id C5616DAD; Fri, 9 May 2014 21:05:28 +0000 (UTC) Received: from bigwig.baldwin.cx (bigwig.baldwin.cx [IPv6:2001:470:1f11:75::1]) (using TLSv1 with cipher DHE-RSA-CAMELLIA256-SHA (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 9BB24399; Fri, 9 May 2014 21:05:28 +0000 (UTC) Received: from jhbbsd.localnet (unknown [209.249.190.124]) by bigwig.baldwin.cx (Postfix) with ESMTPSA id 905AFB976; Fri, 9 May 2014 17:05:26 -0400 (EDT) From: John Baldwin To: Peter Grehan Subject: Re: [rfc] bind per-cpu timeout threads to each CPU Date: Fri, 9 May 2014 16:51:49 -0400 User-Agent: KMail/1.13.5 (FreeBSD/8.4-CBSD-20140415; KDE/4.5.5; amd64; ; ) References: <530508B7.7060102@FreeBSD.org> <536D3184.9070302@freebsd.org> In-Reply-To: <536D3184.9070302@freebsd.org> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <201405091651.49818.jhb@freebsd.org> X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.2.7 (bigwig.baldwin.cx); Fri, 09 May 2014 17:05:26 -0400 (EDT) Cc: Adrian Chadd , freebsd-current , Alexander Motin , "freebsd-arch@freebsd.org" X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 09 May 2014 21:05:28 -0000 On Friday, May 09, 2014 3:50:28 pm Peter Grehan wrote: > > How about i instead do the comprimise: > > > > * i'll pin all other swi's > > * default swi isn't pinned by default, but one can flip on a sysctl at > > boot time to pin it > > > > How's that sound? > > And also please a sysctl that disables any swi pinning. > > It is sometimes useful to change the default cpuset, for instance to > allocate a subset of CPUs to some particular applications and not > FreeBSD. Having kernel threads pinned prevents this from happening since > they are in the default set. > > (Note that some network drivers are also culprits here, though > disabling MSI-x in them is a workaround). I'd actually like a way to exempt certain kernel threads that are inherently per-CPU (such as queues for NIC drivers or per-CPU swi threads) from the default cpuset so that they don't break 'cpuset -l 0 -s 1'. Providing some sort of way to disable the pinning for now should be good, but I think I'd eventually prefer the former suggestion. -- John Baldwin