On Fri, May 20, 2011 at 1:49 AM, Andrei Warkentin <andreiw@xxxxxxxxxxxx> wrote: > On Thu, May 19, 2011 at 11:38 PM, Jaehoon Chung <jh80.chung@xxxxxxxxxxx> wrote: >> Hi Andrei, >> >> Andrei Warkentin wrote: >>> On Wed, May 18, 2011 at 9:37 PM, Jaehoon Chung <jh80.chung@xxxxxxxxxxx> wrote: >>>> Hi Andrei >>>> >>>> Andrei Warkentin wrote: >>>>> CMD23-prefixed instead of open-ended multiblock transfers >>>>> have a performance advantage on some MMC cards. >>>>> >>>> you mentioned about "some MMC cards". >>>> Conversely, that means the some card didn't have a performance advantage? >>>> >>>> Did you find the performance advantage? >>>> if you found the advantage and you can tell me, >>>> i want to know what do you have the some MMC cards.. >>>> >>> >>> I've tested this on a Sandisk eMMC where I saw as good as >>> a 50% improvement on writes (30% real-life use cases). This was a >>> SEM32G 4.3+ part. >> >> Can you tell me your environment? buswidth, AP information, benchmark etc.. >> And if you have the performance result's data, can you share them? >> > > This was on an SDHCI controller (hence the patch...) on a Tegra > 2-based system. I was measuring > throughput on reads and writes (obviously without block cache, > filesystem, etc) to an eMMC card, 8 bits. > > Tested both with my tool (https://github.com/andreiw/superalign) and > an sqllite-based test. > > I'm attaching the data I have. > > A > Additionally, CMD23 use is a requirement for SDXC cards (Arindam can comment on that), as well as for MMC reliable writes and eMMC 4.5-spec features (Yunpeng Gao can comment on that). These patches allow CMD23 use. They do involve a some changes to host controller because of interaction with CMD12, as well as Auto-CMD12 and Auto-CMD23 features. I can definitely consult you if you need help implementing CMD23 support for whatever controller you develop for. A -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
