Hi guys, > On Mar 21, 2019, at 09:03, Mike Looijmans <mike.looijm...@topic.nl> wrote: > > The SD and eMMC controller has become terribly slow in 2018.3: > > # echo 3 > /proc/sys/vm/drop_caches > > # dd if=/dev/mmcblk0 of=/dev/null bs=1M count=20 > 20+0 records in > 20+0 records out > 20971520 bytes (20.0MB) copied, 4.972666 seconds, 4.0MB/s > > # dd if=/dev/mmcblk1 of=/dev/null bs=1M count=20 > 20+0 records in > 20+0 records out > 20971520 bytes (20.0MB) copied, 38.899436 seconds, 526.5KB/s > > > This used to be over 160MB/s for the eMMC (mmcblk0) and over 20 MB/s for the > SD card (mmcblk0) with the 2018.1 kernel and bootloader. > > This is only in Linux, the bootloader still reads at about 10MB/s from the SD > card. So apparently the clocks are set up okay. > > According to the kernel, the clocks and interface are running at full speed: > > # cat /sys/kernel/debug/mmc0/ios > clock: 200000000 Hz > actual clock: 200000000 Hz > vdd: 21 (3.3 ~ 3.4 V) > bus mode: 2 (push-pull) > chip select: 0 (don't care) > power mode: 2 (on) > bus width: 3 (8 bits) > timing spec: 9 (mmc HS200) > signal voltage: 1 (1.80 V) > driver type: 0 (driver type B) > > # cat /sys/kernel/debug/mmc1/ios > clock: 50000000 Hz > actual clock: 50000000 Hz > vdd: 21 (3.3 ~ 3.4 V) > bus mode: 2 (push-pull) > chip select: 0 (don't care) > power mode: 2 (on) > bus width: 2 (4 bits) > timing spec: 2 (sd high-speed) > signal voltage: 0 (3.30 V) > driver type: 0 (driver type B) > > > Any insights?
We also had a long standing performance test which only recently (2018.3) started acting up. Our drill down though showed that is seemed to have been related to previous write operations causing the internal eMMC chip's controller to perform outstanding background operations (BKOPS). We sort of worked around the problem by doing a full blkdiscard of the entire device (because we could) prior to the write test. Not sure if it is related to your query but it might help. Cheers! -- _______________________________________________ meta-xilinx mailing list meta-xilinx@yoctoproject.org https://lists.yoctoproject.org/listinfo/meta-xilinx
