From mboxrd@z Thu Jan 1 00:00:00 1970 From: Simon Horman Date: Wed, 19 Jan 2011 00:09:09 +0000 Subject: SDHC Read Performance Message-Id: <20110119000909.GA9412@verge.net.au> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-mmc@vger.kernel.org, linux-sh@vger.kernel.org Cc: Arnd Hannemann , Guennadi Liakhovetski Hi, I am currently interested in the read performance of the SDHI driver. I ran the following tests on a Mackerel board using Linus's latest tree (6845a44a), which I believe has all of the outstanding patches from Arnd and Guennadi merged. I have made the following crude performance measurements using several different cards. dd if=/dev/mmcblk1 of=/dev/null bsQ2 count0000 SD1.1: 7.0 MB/s SD2.0: 7.0 MB/s SDHC Class 2: 7.1 MB/s SDHC Class 10: 7.2 MB/s Whereas I would expect something like: SD1.1 card: 12 MB/s SD2.0 card: 24 MB/s SDHC Class 2: 24 MB/s SDHC Class 10: Faster? Possibly relevant portions of my .config are: CONFIG_MFD_SH_MOBILE_SDHI=y CONFIG_TMIO_MMC_DMA=y CONFIG_MMC_TMIO=y Arnd, Guennadi, I believe that you have been working on SDHI recently. If you have any suggestions I would be most grateful. Else I will poke some more and see what I can come up with.