----- Ursprüngliche Mail ----- > Von: "Christian Loehle" <CLoehle@xxxxxxxxxxxxxx> > There are probably some more differences if you really want to go down that > rabbit hole, > like different bus modes for uboot and linux. > Anyway I don't really know how I could help you out here, if you could provide a > trace showing the busy times, > that would be a smoking gun for the eMMC vendor. So I went down the rabbit hole. After analyzing the operation traces from Linux and u-boot in more detail I had another chat with the vendor. It turned out their boot area *is* different, it operates on a much larger internal block size. While u-boot does basically all IO with one op code, Linux's writeback via page cache writes 4k wise which leads to catastrophic performance. Using O_DIRECT mitigates the issue, though. Thanks everyone for your valuable input! //richard
