From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:46834) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XuGcl-0007Dc-1u for qemu-devel@nongnu.org; Fri, 28 Nov 2014 03:10:00 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XuGcd-00051W-DT for qemu-devel@nongnu.org; Fri, 28 Nov 2014 03:09:54 -0500 Received: from mx-v6.kamp.de ([2a02:248:0:51::16]:42929 helo=mx01.kamp.de) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XuGcd-00050y-3A for qemu-devel@nongnu.org; Fri, 28 Nov 2014 03:09:47 -0500 Message-ID: <54782DC6.4010704@kamp.de> Date: Fri, 28 Nov 2014 09:09:42 +0100 From: Peter Lieven MIME-Version: 1.0 References: <1417083310-12063-1-git-send-email-pl@kamp.de> <547755FE.10707@redhat.com> In-Reply-To: <547755FE.10707@redhat.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [RFC PATCH] vring: calculate descriptor address directly List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paolo Bonzini , qemu-devel@nongnu.org Cc: kwolf@redhat.com, famz@redhat.com, benoit@irqsave.net, ming.lei@canonical.com, armbru@redhat.com, mreitz@redhat.com, stefanha@redhat.com Am 27.11.2014 um 17:49 schrieb Paolo Bonzini: > > On 27/11/2014 11:15, Peter Lieven wrote: >> vring_map causes a huge overhead by calling memory_region_find everytime. >> the vring_map is executed already on vring_setup and there is also the memory >> region referenced. >> >> Signed-off-by: Peter Lieven > vring_map/unmap is going to disappear and be replaced by > address_space_map/unmap, so for now I'd rather keep it... the issue with vring_map/unmap is that it is called at every vring_pop/push to calculate the descriptor ptr. its ok to call it in vring_setup/destroy and there it doesn't hurt. looking at address_space_map/unmap this would be expensive as well if it is called in every vring_pop/push. Peter