From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:36924) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SwGnF-0006Ea-L5 for qemu-devel@nongnu.org; Tue, 31 Jul 2012 14:03:46 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1SwGnE-00060e-Jd for qemu-devel@nongnu.org; Tue, 31 Jul 2012 14:03:41 -0400 Received: from mailout1.w1.samsung.com ([210.118.77.11]:15373) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SwGnE-000606-E9 for qemu-devel@nongnu.org; Tue, 31 Jul 2012 14:03:40 -0400 Received: from eusync4.samsung.com (mailout1.w1.samsung.com [210.118.77.11]) by mailout1.w1.samsung.com (Oracle Communications Messaging Server 7u4-24.01(7.0.4.24.0) 64bit (built Nov 17 2011)) with ESMTP id <0M8100E8IE6TC5B0@mailout1.w1.samsung.com> for qemu-devel@nongnu.org; Tue, 31 Jul 2012 19:04:05 +0100 (BST) Received: from [106.109.9.180] by eusync4.samsung.com (Oracle Communications Messaging Server 7u4-24.01(7.0.4.24.0) 64bit (built Nov 17 2011)) with ESMTPA id <0M81006CGE5TNF30@eusync4.samsung.com> for qemu-devel@nongnu.org; Tue, 31 Jul 2012 19:03:37 +0100 (BST) Message-id: <50181DF1.2050308@samsung.com> Date: Tue, 31 Jul 2012 22:03:29 +0400 From: Igor Mitsyanko MIME-version: 1.0 References: <1343417387-13953-1-git-send-email-i.mitsyanko@samsung.com> <1343417387-13953-11-git-send-email-i.mitsyanko@samsung.com> <501816D0.9040207@samsung.com> In-reply-to: Content-type: text/plain; charset=UTF-8; format=flowed Content-transfer-encoding: 7bit Subject: Re: [Qemu-devel] [PATCH V4 10/12] SD card users: optimize access to SDClass methods List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Peter Maydell Cc: kwolf@redhat.com, Anthony Liguori , benoit.canet@gmail.com, wdongxu@linux.vnet.ibm.com, stefanha@linux.vnet.ibm.com, e.voevodin@samsung.com, qemu-devel@nongnu.org, armbru@redhat.com, andrew.zaborowski@intel.com, kyungmin.park@samsung.com, pbonzini@redhat.com On 07/31/2012 09:47 PM, Peter Maydell wrote: > On 31 July 2012 18:33, Igor Mitsyanko wrote: >> On 07/31/2012 07:43 PM, Peter Maydell wrote: >>> Anthony claims that SD_GET_CLASS should be cheap enough that we don't >>> need to hoist it out of loops like this. Do you have profiling data >>> or similar that caused you to write this patch? >> Well, I've tested it by measuring an execution time of a 4Kb write to SD >> card, results showed that arithmetic mean of time for one 4k write was less >> by ~300us in sequence with SD_GET_CLASS extracted from the loop. > How much is that as a % of the total time for the write ? > > -- PMM > total write time was ~3.5-4.0 ms I think, so its ~0.08%