From mboxrd@z Thu Jan 1 00:00:00 1970 From: merez@codeaurora.org Subject: RE: [PATCH v7 1/3] mmc: core: Add packed command feature of eMMC4.5 Date: Tue, 12 Jun 2012 12:15:21 -0700 (PDT) Message-ID: <113bb1f38dbc386f1adfc580e10dc2e5.squirrel@www.codeaurora.org> References: <000601cd47ab$8ad77c50$a08674f0$%jun@samsung.com> <000001cd489c$115f03b0$341d0b10$%jun@samsung.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT Return-path: Received: from wolverine01.qualcomm.com ([199.106.114.254]:31827 "EHLO wolverine01.qualcomm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751612Ab2FLTPW (ORCPT ); Tue, 12 Jun 2012 15:15:22 -0400 In-Reply-To: <000001cd489c$115f03b0$341d0b10$%jun@samsung.com> Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: Seungwon Jeon Cc: "'S, Venkatraman'" , linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org, 'Chris Ball' , 'Maya Erez' , 'Subhash Jadavani' > S, Venkatraman wrote: >> On Mon, Jun 11, 2012 at 1:53 PM, Seungwon Jeon >> wrote: >> > This patch adds packed command feature of eMMC4.5. >> > The maximum number for packing read(or write) is offered >> > and exception event relevant to packed command which is >> > used for error handling is enabled. If host wants to use >> > this feature, MMC_CAP2_PACKED_CMD should be set. >> > >> > Signed-off-by: Seungwon Jeon >> >> Can you please post some clear performance benchmarks with your patchset >> ? >> Given that #merez claims to see a significant performance drop for >> reads, it will be >> good to compare notes. >> If it's not too much trouble, both CFQ and deadline scheduler figures >> would be useful, on a >> set of read only, write only and parallel read write usecases. >> >> I can also try to replicate your results if you can publish the exact >> configuration you used >> for testing (example: iozone parameters) > I'm checking the merez's result. > Currently packed command is effective on write. > When running packed write with iozone, there is 25% performance gains. > (ex: iozone -az -i0 -I -s 10m -f /target/test -e) > Our tests shows performance gain of 50-60% in scenarios of only write lmdd operations. As I mentioned in the write packing control thread the degradation of read performance in case of mix read/write operations appears also without write packing. Therefore I don't think it should stop us from approving the write packing patch, that gives a significant improvement to the write performance. The read performance degradation should be resolved regardless of the write packing patch. Thanks, Maya Erez -- Sent by consultant of Qualcomm Innovation Center, Inc. Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum