Konstantin, Thank you for update. We also are reviewing file IO operations scheduler . Looks like for eMMC current scheduler is not good tailored (since eMMC is not hard drive :) ) Sergey On Wed, Jan 9, 2013 at 12:15 AM, Konstantin Dorfman <kdorfman@xxxxxxxxxxxxxx> wrote: > Hello Sergey, > > I'm working on the same flow - to reduce read latency hit (as a result of > big aggregated writes). I plan to send all relevant patches to the mailing > list soon and it will be great if you can test them on your system. > > There are requirements for this flow is: > - eMMC 4.5 supported by card (this means HPI) > - host controller shoud implement stop request api (that is be able > correctly stop DMA & all internal state and be ready for next read > transaction. > > Right now, please look at this patches as reference: > > 1. [RFC/PATCH 0/2] Handling urgent and new request notifications. > 2. [RFC/PATCH 1/2] mmc: Urgent data request flow. > > This is old changes, just for the solution overview. > > Thanks, > >> Hi Venkat, >> >> I was looking for some explanations of eMMC behavior in products we are >> developing now and found your comments around eMMC here. Our observation >> shows >> that that eMMC performance vary significantly and depends on volume of >> data to >> write during time slot and temperature. After a heavy write test was run >> for >> some time for a good performance eMMC (showing 10-12MB/s of the write >> performance on big blocks) its write performance degraded to the 4-5MB/s. >> We even observed performance lowest level as 65KB/s! >> There are a lot of Write type of operations necessary into dedicated eMMC >> partition by requirements. >> The side effect is that long write operations block Application UI to >> redraw >> the views because it requires Read operations. >> Visually we see “Blank Dark Screen†for few seconds and even ANRs. So >> HMI may >> help us. >> >> Question: Did you finish research with HPI to try ? Which type of eMMC >> did >> you use? >> >> P.S. We use TI BSP for OMAP3630 for Android >> >> >> -- >> 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 >> > -- 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
