From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:33538) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1azlfL-00056z-1E for qemu-devel@nongnu.org; Mon, 09 May 2016 09:56:10 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1azlfE-0001ia-13 for qemu-devel@nongnu.org; Mon, 09 May 2016 09:56:05 -0400 Received: from mx1.redhat.com ([209.132.183.28]:59806) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1azlfD-0001iW-RQ for qemu-devel@nongnu.org; Mon, 09 May 2016 09:55:59 -0400 References: <20160425152528.GA16402@flamenco> <1461627983-32563-1-git-send-email-cota@braap.org> <87shy8ev7c.fsf@linaro.org> <20160430034035.GA31609@flamenco> <573072CE.3070808@redhat.com> <87bn4fzc0g.fsf@linaro.org> From: Paolo Bonzini Message-ID: <573096EA.9070507@redhat.com> Date: Mon, 9 May 2016 15:55:54 +0200 MIME-Version: 1.0 In-Reply-To: <87bn4fzc0g.fsf@linaro.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [RFC v3] translate-all: protect code_gen_buffer with RCU List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: =?UTF-8?Q?Alex_Benn=c3=a9e?= Cc: "Emilio G. Cota" , QEMU Developers , MTTCG Devel , Peter Crosthwaite , Richard Henderson , Sergey Fedorov On 09/05/2016 13:50, Alex Benn=C3=A9e wrote: > > Which locks? tb_lock during tb_find_fast? The problem with that was > > that it slowed down everything a lot, wasn't it? >=20 > Very much so, in the new tree (coming soon) with QHT I was able to > remove the locks from the whole hot-path which means they where only > needed for code generation. Okay, I'm curious now. :) > > To me, the RCU idea is not really about making tb_flush (the rare cas= e) > > faster; it was more about keeping the rest simple and fast. >=20 > I'm not sure it achieved that as there is added complexity from having > the split buffer and then ensuring you don't double-flush. Agreed. Paolo