Re: [PATCH V2 0/2] mmc: hsq: Dynamically adjust hsq_depth to improve performance

[Ulf Hansson]

On Wed, 23 Aug 2023 at 08:18, Wenchao Chen <wenchao.chen@xxxxxxxxxx> wrote:
>
> Change in v2:
> - Support for dynamic adjustment of hsq_depth.
>
> Test
> =====
> I tested 3 times for each case and output a average speed.
> Ran 'fio' to evaluate the performance:
> 1.Fixed hsq_depth
> 1) Sequential write:
> Speed: 168 164 165
> Average speed: 165.67MB/S
>
> 2) Sequential read:
> Speed: 326 326 326
> Average speed: 326MB/S
>
> 3) Random write:
> Speed: 82.6 83 83
> Average speed: 82.87MB/S
>
> 4) Random read:
> Speed: 48.2 48.3 47.6
> Average speed: 48.03MB/S
>
> 2.Dynamic hsq_depth
> 1) Sequential write:
> Speed: 167 166 166
> Average speed: 166.33MB/S
>
> 2) Sequential read:
> Speed: 327 326 326
> Average speed: 326.3MB/S
>
> 3) Random write:
> Speed: 86.1 86.2 87.7
> Average speed: 86.67MB/S
>
> 4) Random read:
> Speed: 48.1 48 48
> Average speed: 48.03MB/S
>
> Based on the above data, dynamic hsq_depth can improve the performance of random writes.
> Random write improved by 4.6%.

Thanks for sharing this, interesting!

>
> Test cmd
> =========
> 1)write: fio -filename=/dev/mmcblk0p72 -direct=1 -rw=write -bs=512K -size=512M -group_reporting -name=test -numjobs=8 -thread -iodepth=64
> 2)read: fio -filename=/dev/mmcblk0p72 -direct=1 -rw=read -bs=512K -size=512M -group_reporting -name=test -numjobs=8 -thread -iodepth=64
> 3)randwrite: fio -filename=/dev/mmcblk0p72 -direct=1 -rw=randwrite -bs=4K -size=512M -group_reporting -name=test -numjobs=8 -thread -iodepth=64
> 4)randread: fio -filename=/dev/mmcblk0p72 -direct=1 -rw=randread -bs=4K -size=512M -group_reporting -name=test -numjobs=8 -thread -iodepth=64
>

The buffer you used for randwrite/randread is 4K blocks. Did you try
with something bigger too?

Or maybe we are afraid of introducing a bigger latency if we
dynamically change the hsq_depth to match something bigger than 4K?

>
> Wenchao Chen (2):
>   mmc: queue: replace immediate with hsq->depth
>   mmc: hsq: dynamic adjustment of hsq->depth
>
>  drivers/mmc/core/queue.c   |  6 +-----
>  drivers/mmc/host/mmc_hsq.c | 27 +++++++++++++++++++++++++++
>  drivers/mmc/host/mmc_hsq.h |  8 ++++++++
>  include/linux/mmc/host.h   |  1 +
>  4 files changed, 37 insertions(+), 5 deletions(-)
>

Kind regards
Uffe