> Can it be that rcar-gen3-sdhi changes some timings after switching? > Either in software or on hardware. Neither should be aware of the notion of a boot or user area partition. Anything below mmc/core isn't, if we exclude the boot operation which is read only, so not applicable to your problem. So also a while true; do dd if=/dev/zero of=/dev/mmcblkXboot0 bs=128K status=progress; done gives you like ~50KB/s consistently? -----Original Message----- From: Richard Weinberger <richard@xxxxxx> Sent: Tuesday, April 18, 2023 10:11 AM To: Christian Loehle <CLoehle@xxxxxxxxxxxxxx> Cc: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>; linux-mmc <linux-mmc@xxxxxxxxxxxxxxx>; linux-renesas-soc <linux-renesas-soc@xxxxxxxxxxxxxxx>; wsa+renesas <wsa+renesas@xxxxxxxxxxxxxxxxxxxx>; ulf hansson <ulf.hansson@xxxxxxxxxx> Subject: Re: Poor write performance to boot area using rcar-gen3-sdhi ----- Ursprüngliche Mail ----- > Von: "Christian Loehle" <CLoehle@xxxxxxxxxxxxxx> Your eMMC likely > treats the boot partitions differently than the user area, e.g. > in regards to cache. > Is this reproducible for more 4k writes? What about larger writes? Yes. So far every write size I tried is slow. Sometimes (1 out of 50) small writes are fast, that's most likely a caching effect of eMMC internals. > The eMMC might not even have the mapping available after boot and > first has to internally switch to it, in contrast to at u-boot stage? Wouldn't that explain only the first slow write? I see poor write speed also on repeated runs. > Anyway this is probably more a question to your eMMC manufacturer and > nothing the host is to be blamed, as you mentioned yourself, the time > is spent at CMD25. The eMMC manufacturer says there is nothing special about the boot area and write speed should be equally fast. Can it be that rcar-gen3-sdhi changes some timings after switching? Either in software or on hardware. Thanks, //richard Hyperstone GmbH | Reichenaustr. 39a | 78467 Konstanz Managing Director: Dr. Jan Peter Berns. Commercial register of local courts: Freiburg HRB381782
