On 13/10/20 3:32 pm, Ulf Hansson wrote: > + Adrian > > On Tue, 13 Oct 2020 at 13:09, Jisheng Zhang <Jisheng.Zhang@xxxxxxxxxxxxx> wrote: >> >> Hi, >> >> I found an emmc performance regression with below simple benchmark cmd: >> >> dd if=/dev/mmcblk0 of=/dev/null bs=8192 count=100000 >> >> This regression has been bisected to commit >> 427b6514d0953bf (“mmc: sdhci: Add Auto CMD Auto Select support”) >> >> If I revert this commit, the performance is good now. >> >> I’m not sure whether this is common issue or not. > > Can you provide some data, like how much is the regression and how > many tests did you run? > > Did you try different block sizes of the dd command? Also what is the SDHCI version? The patch in question is for version >= 4.1 What driver? Can you tell if the patch changed which auto command is used?
