RE: [RFC PATCH] mmc: core: Disable REQ_FUA if the eMMC supports an internal cache

[Avri Altman]

Hi,
> I have benchmarked the FUA/Cache behavior a bit.
> I don't have an actual filesystem benchmark that does what I wanted and is
> easy to port to the target so I used:
I guess I'm a bit late here - sorry about that.
If you happened to have traces of the below runs - I'll be happy to provide further analysis.

You might also want to look into fio which allows you do write to a raw block device,
And has various sync options - so you are much more in control of the payload size
And how many reliable-writes / sync-caches were issued - if any.
  
Thanks,
Avri

> # call with
> # for loop in {1..3}; do sudo dd if=/dev/urandom bs=1M of=/dev/mmcblk2;
> done; for loop in {1..5}; do time ./filesystembenchmark.sh; umount /mnt;
> done
> mkfs.ext4 -F /dev/mmcblk2
> mount /dev/mmcblk2 /mnt
> for i in {1..3}
> do
> cp -r linux-6.2.2 /mnt/$i
> done
> for i in {1..3}
> do
> rm -r /mnt/$i
> done
> for i in {1..3}
> do
> cp -r linux-6.2.2 /mnt/$i
> done
> 
> 
> I found a couple of DUTs that I can link, I also tested one industrial card.
> 
> DUT1: blue PCB Foresee eMMC
> https://pine64.com/product/32gb-emmc-module/
> DUT2: green PCB SiliconGo eMMC
> Couldn't find that one online anymore unfortunately
> DUT3: orange hardkernel PCB 8GB
> https://www.hardkernel.com/shop/8gb-emmc-module-c2-android/
> DUT4: orange hardkernel PCB white dot
> https://rlx.sk/en/odroid/3198-16gb-emmc-50-module-xu3-android-for-
> odroid-xu3.html
> DUT5: Industrial card
> 
> 
> The test issued 461 DO_REL_WR during one of the iterations for DUT5
> 
> DUT1:
> Cache, no FUA:
> 13:04.49
> 13:13.82
> 13:30.59
> 13:28:13
> 13:20:64
> FUA:
> 13:30.32
> 13:36.26
> 13:10.86
> 13:32.52
> 13:48.59
> 
> DUT2:
> FUA:
> 8:11.24
> 7:47.73
> 7:48.00
> 7:48.18
> 7:47.38
> Cache, no FUA:
> 8:10.30
> 7:48.97
> 7:48.47
> 7:47.93
> 7:44.18
> 
> DUT3:
> Cache, no FUA:
> 7:02.82
> 6:58.94
> 7:03.20
> 7:00.27
> 7:00.88
> FUA:
> 7:05.43
> 7:03.44
> 7:04.82
> 7:03.26
> 7:04.74
> 
> DUT4:
> FUA:
> 7:23.92
> 7:20.15
> 7:20.52
> 7:19.10
> 7:20.71
> Cache, no FUA:
> 7:20.23
> 7:20.48
> 7:19.94
> 7:18.90
> 7:19.88
> 
> Cache, no FUA:
> 7:19.36
> 7:02.11
> 7:01.53
> 7:01.35
> 7:00.37
> Cache, no FUA CQE:
> 7:17.55
> 7:00.73
> 6:59.25
> 6:58.44
> 6:58.60
> FUA:
> 7:15.10
> 6:58.99
> 6:58.94
> 6:59.17
> 6:60.00
> FUA CQE:
> 7:11.03
> 6:58.04
> 6:56.89
> 6:56.43
> 6:56:28
> 
> If anyone has any comments or disagrees with the benchmark, or has a
> specific eMMC to test, let me know.
> 
> Regards,
> Christian
> 
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