On Mon, Sep 27, 2021 at 03:03:28PM -0700, Bart Van Assche wrote: > In addition to reverting commit 7b05bf771084 ("Revert "block/mq-deadline: > Prioritize high-priority requests""), this patch uses 'jiffies' instead > of ktime_get() in the code for aging lower priority requests. Considering that this is basically a revert of a revert, except for the ktime_get() to jiffies change, I think that you should state the reason for this change in the change log. > Ran the following script: > > set -e > scriptdir=$(dirname "$0") > if [ -e /sys/module/scsi_debug ]; then modprobe -r scsi_debug; fi > modprobe scsi_debug ndelay=1000000 max_queue=16 > sd='' > while [ -z "$sd" ]; do > sd=$(basename /sys/bus/pseudo/drivers/scsi_debug/adapter*/host*/target*/*/block/*) > done > echo $((100*1000)) > "/sys/block/$sd/queue/iosched/prio_aging_expire" > if [ -e /sys/fs/cgroup/io.prio.class ]; then > cd /sys/fs/cgroup > echo restrict-to-be >io.prio.class > echo +io > cgroup.subtree_control > else > cd /sys/fs/cgroup/blkio/ > echo restrict-to-be >blkio.prio.class > fi > echo $$ >cgroup.procs > mkdir -p hipri > cd hipri > if [ -e io.prio.class ]; then > echo none-to-rt >io.prio.class > else > echo none-to-rt >blkio.prio.class > fi > { "${scriptdir}/max-iops" -a1 -d32 -j1 -e mq-deadline "/dev/$sd" >& ~/low-pri.txt & } > echo $$ >cgroup.procs > "${scriptdir}/max-iops" -a1 -d32 -j1 -e mq-deadline "/dev/$sd" >& ~/hi-pri.txt > > Result: > * 11000 IOPS for the high-priority job > * 40 IOPS for the low-priority job > > If the prio aging expiry time is changed from 100s into 0, the IOPS results > change into 6712 and 6796 IOPS. > > The max-iops script is a script that runs fio with the following arguments: > --bs=4K --gtod_reduce=1 --ioengine=libaio --ioscheduler=${arg_e} --runtime=60 > --norandommap --rw=read --thread --buffered=0 --numjobs=${arg_j} > --iodepth=${arg_d} --iodepth_batch_submit=${arg_a} > --iodepth_batch_complete=$((arg_d / 2)) --name=${positional_argument_1} > --filename=${positional_argument_1} > > Cc: Damien Le Moal <damien.lemoal@xxxxxxx> > Cc: Niklas Cassel <Niklas.Cassel@xxxxxxx> > Cc: Hannes Reinecke <hare@xxxxxxx> > Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx> > --- With an elaborated change log, this looks good to me: Reviewed-by: Niklas Cassel <niklas.cassel@xxxxxxx>