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

[Wenchao Chen]

On Thu, Aug 24, 2023 at 6:26 PM Ulf Hansson <ulf.hansson@xxxxxxxxxx> wrote:
>
> 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?
>
Hi Uffe
I tried bs=8k and bs=16k, the random read and random write performance
improvement was not noticeable.

1.Fixed hsq_depth
1) Random write(bs=8K):
Speed: 116 114 115
Average speed: 115MB/S

2) Random read(bs=8K):
Speed: 83 83 82.5
Average speed: 82.8MB/S

3) Random write(bs=16K):
Speed: 141 142 141
Average speed: 141.3MB/S

4) Random read(bs=16K):
Speed: 132 132 132
Average speed: 132MB/S

2.Dynamic hsq_depth
1) Random write(bs=8K):
Speed: 115 115 115
Average speed: 115MB/S

2) Random read(bs=8K):
Speed: 82.7 82.9 82.8
Average speed: 82.8MB/S

3) Random write(bs=16K):
Speed: 143 141 141
Average speed: 141.6MB/S

4) Random read(bs=16K):
Speed: 132 132 132
Average speed: 132MB/S

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

Increasing hsq_depth cannot improve 8k and 16k random read/write performance.
To reduce latency, we dynamically increase hsq_depth only for 4k random writes.

> >
> > 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