Date: Tue, 03 Mar 2015 01:20:06 -0800 From: Julian Elischer <julian@freebsd.org> To: Neel Natu <neelnatu@gmail.com>, Davide Italiano <davide@freebsd.org> Cc: John-Mark Gurney <jmg@freebsd.org>, "svn-src-head@freebsd.org" <svn-src-head@freebsd.org>, "svn-src-all@freebsd.org" <svn-src-all@freebsd.org>, "src-committers@freebsd.org" <src-committers@freebsd.org> Subject: Re: svn commit: r279539 - head/sys/sys Message-ID: <54F57CC6.9050109@freebsd.org> In-Reply-To: <CAFgRE9HR_BwWfyLVoDY0kS8rXK5p=zE0vgeCY5Ffk65ikAr2zg@mail.gmail.com> References: <201503022005.t22K5HTL062907@svn.freebsd.org> <CACYV=-FXuxzTqx12odFSRE98ydMd_AtK2GxKzv7bvLBbkAyr0A@mail.gmail.com> <CAFgRE9HR_BwWfyLVoDY0kS8rXK5p=zE0vgeCY5Ffk65ikAr2zg@mail.gmail.com>
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On 3/2/15 4:55 PM, Neel Natu wrote: > Hi Davide, > > On Mon, Mar 2, 2015 at 12:26 PM, Davide Italiano <davide@freebsd.org> wrote: >> On Mon, Mar 2, 2015 at 12:05 PM, John-Mark Gurney <jmg@freebsd.org> wrote: >>> Author: jmg >>> Date: Mon Mar 2 20:05:16 2015 >>> New Revision: 279539 >>> URL: https://svnweb.freebsd.org/changeset/base/279539 >>> >>> Log: >>> give others fair warning that _SPARE2 isn't just cxgb, but used by large >>> number of other subsystems, so you probably don't want _SPARE2.. >>> >>> ktr needs an overhaul to really only compile in the ones you want, >>> we've long passed the 31 bits it provides.. >>> >> If you really want to do the overhaul (which would be honestly great), >> I might consider revamping my work for per-cpu KTR buffer and include >> that in the change. Originally it was just an exercise, but then it >> evolved and I've been sitting with it in my local tree for a while. I >> never had the chutzpah to upstream it because it involves fundamental >> changes and breaks compatibility with the old ktrdump(1) format. >> A rather outdated (and maybe not completely functional) version of the >> patch can be found here: >> http://people.freebsd.org/~davide/locking/ktr_percpu.4.diff , which >> should give you an high level view of the change. >> I can update it to the last version and bring up for review, if >> somebody think it might be a sane idea avoiding synchronization on a >> single buffer for KTR. I think it would be a problem... one of the truely useful things about ktr is that it does use a single buffer. this means that you get the true interaction between CPUS. Schedgraph relies on this (as one example). > This would be a very welcome improvement. > > best > Neel > >> -- >> Davide >> > >
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