----- Ursprüngliche Mail ----- > Von: "Christian Loehle" <CLoehle@xxxxxxxxxxxxxx> >> 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. > > Interesting, without having tried it out I would expect the 4k writebacks to be > merged to a bigger IO, too? Given that they are filled sequentially, which is > the case. > But good that you got it working. > If I find the time I will play with it a bit. I think due to the nature of rcar-gen3-sdhi merging of these BIOs is not possible. There seems to be support for some variants, though: https://elinux.org/R-Car/Merging-MMC-block-requests Not sure whether I find the time to dig down that rabbit whole too. ;-) Thanks, //richard
