Hi Linus, On 2017/2/17 21:22, Linus Walleij wrote: > On Fri, Feb 17, 2017 at 12:53 PM, Ziji Hu <huziji@xxxxxxxxxxx> wrote: > >> I would like to suggest that you should try the multiple thread >> test mode of iozone, since you are testing *Multi* Queue. > > Good point. This target has only 2 CPUs but still, maybe it performs! > In my very own opinion, (although I'm not the expert of marketing), quad-core platforms will be more and more popular. Quad-core might have a different result, especially when we are testing multiple threads. >> Besides, it seems that your eMMC transfer speed is quite low. >> It is normal that read speed can reach more than 100MB/s in HS400. >> Could you try a higher speed mode? The test result might be >> limited by the bus clock frequency. > > The iozone tests are done on an SDcard. And I only did read tests on > the eMMC I have. > > It's because I'm afriad of wearing out my eMMC :( > > But OK I'll just take the risk and run iozone on the eMMC. > Actually, there is a parameter to limit the size of test file in iozone. I'm not sure why you need to scan the whole eMMC. But I personally believe it is unnecessary. Sorry for delay reply. Hope your eMMC is not broken yet. :p eMMC usually contains much more physical pages than the capacity it shows. Thus I guess your eMMC should be fine unless you torture it by entirely writing it again and again. >> Actually I have been following your thread for some time. >> But currently I'm a little confused. >> May I know the purpose of your patch? > > Ulf describes it: we want to switch MMC/SD to MQ. > > To me, there are two reasons for that (no secret agendas...) > > 1. To get away from the legacy codebase in the old block layer. > Christoph and Jens have been very clear stating that the old block > layer is in maintenance mode and should be phased out, and they > asked explicitly for out help to do so. Currently > MMC/SD is a big fat roadblock to these plans so it is win-win for > MMC/SD and the block layer if we can just switch over to MQ. > > 2. My colleague Paolo Valente is working on the next generation > block scheduler BFQ which has very promising potential for > interactive loads. (Like taking a backup of your harddrive while > playing 1080p video let's say.) Since the > old block layer is no longer maintained, this scheduler will only > be merged and made available for systems deploying MQ. He's > already working full steam on that. > > I would like to make 1+2 happen in the next merge window > ultimately, but yeah, maybe I'm overly optimistic. But I will sure > try. I see. Thank you for the details. > > Maybe I should add: > > 3. MQ is a better and future-proof fit for command queueing. I strongly agree with you on it. Thank you. Best regards, Hu Ziji > > Yours, > Linus Walleij >
