RE: [PATCH 00/16] multiqueue for MMC/SD third try

Avri Altman
2017-02-11T13:03:03Z

>
> The iozone results seem a bit consistent and all values seem to be noisy and
> not say much. I don't know why really, maybe the test is simply not relevant,
> the tests don't seem to be significantly affected by any of the patches, so
> let's focus on the dd and find tests.

Maybe use a more selective testing mode instead of -az.
Also maybe you want to clear the cache between the sequential and random tests:
#sync
#echo 3 > /proc/sys/vm/drop_caches
#sync
It helps to obtain a more robust results.

> What immediately jumps out at you is that linear read/writes perform just as
> nicely or actually better with MQ than with the old block layer.

How come 22.7MB/s before vs. 22.1MB/s after is better? or did I misunderstand the output?
Also as dd is probably using the buffer cache, unlike the iozone test in which you properly used -I
for direct mode to isolate the blk-mq effect - does it really say much?