From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:56757) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XvkUC-0005ig-Ky for qemu-devel@nongnu.org; Tue, 02 Dec 2014 05:15:17 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XvkU7-0007kP-Qp for qemu-devel@nongnu.org; Tue, 02 Dec 2014 05:15:12 -0500 Received: from mx1.redhat.com ([209.132.183.28]:32920) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XvkU7-0007jA-Ir for qemu-devel@nongnu.org; Tue, 02 Dec 2014 05:15:07 -0500 Date: Tue, 2 Dec 2014 10:14:38 +0000 From: "Dr. David Alan Gilbert" Message-ID: <20141202101437.GC2907@work-vm> References: <8E7B9828-1AB9-45A2-BDB5-40518B768BC1@greensocs.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <8E7B9828-1AB9-45A2-BDB5-40518B768BC1@greensocs.com> Subject: Re: [Qemu-devel] Update on TCG Multithreading List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Mark Burton Cc: Peter Maydell , Bastian Koppelmann , qemu-devel , Alexander Graf , pavel Dovgaluk , Paolo Bonzini , Alex Benn?e , Llu?s Vilanova , KONRAD Fr?d?ric * Mark Burton (mark.burton@greensocs.com) wrote: > > All - first a huge thanks for those who have contributed, and those who have expressed an interest in helping out. > > One issue I???d like to see more opinions on is the question of a cache per core, or a shared cache. > I have heard anecdotal evidence that a shared cache gives a major performance benefit???. > Does anybody have anything more concrete? > (of course we will get numbers in the end if we implement the hybrid scheme as suggested in the wiki - but I???d still appreciate any feedback). > > Our next plan is to start putting an implementation plan together. Probably quite sketchy at this point, and we hope to start coding shortly. I'd expect a shared one to be able to take advantage of code that's translated by one core and then used on another. On the other hand with one per core you can perform updates on the caches with a lot less locking; however you've still got to be able to do invalidates across all the caches if any core does the write, and that could also get tricky. Dave > > > Cheers > > Mark. > > > > > > +44 (0)20 7100 3485 x 210 > +33 (0)5 33 52 01 77x 210 > > +33 (0)603762104 > mark.burton > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK