Re: Some throughput tests with MQ and BFQ on MMC/SD

[Ziji Hu <huziji@marvell.com>]

Hi Linus,

On 2017/2/17 17:33, Linus Walleij wrote:
> This week I tested the following:
> 
> - Merge the in-flight BFQ work from Paolo with my MMC MQ patch set
> - Enable BFQ
> - Run a few iterations of classic throughput tests
> 
> dd on whole internal eMMC, 7.38 GiB:
> 
> sync
> echo 3 > /proc/sys/vm/drop_caches
> sync
> time dd if=/dev/mmcblk3 of=/dev/null
> time dd if=/dev/mmcblk3 of=/dev/null bs=1M
> 
> iozone on a Noname SD card 2GB
> 
> mount /dev/mmcblk0p1 /mnt
> sync
> echo 3 > /proc/sys/vm/drop_caches
> sync
> iozone -az -i0 -i1 -i2 -s 20m -I -f /mnt/foo.test
> 
> The results:
> 
> Before patches (v4.10-rc8):
> 
> 7918845952 bytes (7.4GB) copied, 194.504059 seconds, 38.8MB/s
> real    3m 14.51s
> user    0m 7.41s
> sys     1m 10.34s
> 
> 7918845952 bytes (7.4GB) copied, 176.519531 seconds, 42.8MB/s
> real    2m 56.53s
> user    0m 0.06s
> sys     0m 36.57s
> 
> Command line used: iozone -az -i0 -i1 -i2 -s 20m -I -f /mnt/foo.test
> Output is in kBytes/sec
> 
>                                                    random    random
>    kB  reclen    write  rewrite    read    reread    read     write
> 20480       4     1960     2105     5991     6023     5202       40
> 20480       8     4636     4901     9087     9103     9066       80
> 20480      16     5522     5663    12237    12242    12206      163
> 20480      32     5976     6031    14915    14917    14901      333
> 20480      64     6286     6387    16737    16763    16738      678
> 20480     128     6720     6757    17876    17857    17865     1403
> 20480     256     6846     6909    18230    17568    16719     3039
> 20480     512     7204     7229    18471    18751    18834     7209
> 20480    1024     7257     7315    18684    18044    18095     7337
> 20480    2048     7322     7388    18605    18802    19437     7401
> 20480    4096     7553     7652    21510    21108    21503     7688
> 20480    8192     7534     7745    22164    22300    22490     7758
> 20480   16384     7357     7818    23053    23048    23056     7834
> 
> 
> After MMC MQ patches:
> 
> 7918845952 bytes (7.4GB) copied, 196.907776 seconds, 38.4MB/s
> real    3m 16.91s
> user    0m 7.17s
> sys     1m 8.03s
> 
> 7918845952 bytes (7.4GB) copied, 192.595734 seconds, 39.2MB/s
> real    3m 12.60s
> user    0m 0.12s
> sys     0m 33.11s
> 
> Command line used: iozone -az -i0 -i1 -i2 -s 20m -I -f /mnt/foo.test
>                                                    random    random
>    kB  reclen    write  rewrite    read    reread    read     write
> 20480       4     2049     2154     5991     5998     5934       40
> 20480       8     4654     4921     9081     9075     9028       81
> 20480      16     5572     5747    12250    12252    12177      164
> 20480      32     6040     6084    14858    14895    14833      335
> 20480      64     6370     6449    16759    16770    16715      682
> 20480     128     6834     6814    17882    17843    17878     1411
> 20480     256     6892     6900    18526    18105    18430     3066
> 20480     512     7239     7254    18839    18864    18837     7258
> 20480    1024     7342     6453    18787    18161    17522     7343
> 20480    2048     7408     7439    17891    18211    19029     7472
> 20480    4096     7641     7703    20950    21044    20900     7705
> 20480    8192     7584     7811    22261    22170    22385     7809
> 20480   16384     7407     7873    23033    23050    23048     7905
> 
> 
> After MMC MQ+BFQ patches:
> 
> 7918845952 bytes (7.4GB) copied, 197.097717 seconds, 38.3MB/s
> real    3m 17.10s
> user    0m 7.67s
> sys     1m 7.33s
> 
> 7552+0 records in
> 7552+0 records out
> 7918845952 bytes (7.4GB) copied, 187.119538 seconds, 40.4MB/s
> real    3m 7.12s
> user    0m 0.11s
> sys     0m 34.61s
> 
> Command line used: iozone -az -i0 -i1 -i2 -s 20m -I -f /mnt/foo.test
> Output is in kBytes/sec
>                                                    random    random
>    kB  reclen    write  rewrite    read    reread    read     write
> 20480       4     1734     1786     5923     5166     5894       40
> 20480       8     4614     4853     8950     8949     8909       80
> 20480      16     5525     5705    12086    12098    12040      164
> 20480      32     6027     6040    14765    14793    14755      334
> 20480      64     6341     6404    16696    16697    16670      680
> 20480     128     6799     6842    17830    17833    17814     1407
> 20480     256     6848     6849    17394    18251    17537     3054
> 20480     512     7191     7229    18545    18628    18801     7224
> 20480    1024     7241     7331    17845    17909    18206     7302
> 20480    2048     7375     7433    18794    19288    19675     7426
> 20480    4096     7583     7696    21024    21194    21082     7659
> 20480    8192     7555     7767    22068    22170    22168     7808
> 20480   16384     7350     7831    23021    23032    23050     7870
> 

	I would like to suggest that you should try the multiple thread
	test mode of iozone, since you are testing *Multi* Queue.

	Besides, it seems that your eMMC transfer speed is quite low.
	It is normal that read speed can reach more than 100MB/s in HS400.
	Could you try a higher speed mode? The test result might be
	limited by the bus clock frequency.	

> 
> As you can see there are no huge performance regressions with these
> kinds of "raw" throughput tests.
> 
> These iozone figures are unintuitive unless your head can
> plot logarithmic, look at the charts here for a more visual presentation
> of the iozone results:
> https://docs.google.com/spreadsheets/d/1rm72TiGlTnzDeGLR__aqvjcJ2UkA-Ro3-XyKA8r1M-c
> 
> Compare this to the performance change we got when first introducing
> the asynchronous requests:
> https://wiki.linaro.org/WorkingGroups/KernelArchived/Specs/StoragePerfMMC-async-req
> 
> The patches need some issues fixed from the build server
> complaints and some robustness hammering, but after that I
> think they will be ripe for merging for v4.12.
> 

	Actually I have been following your thread for some time.
	But currently I'm a little confused.
	May I know the purpose of your patch?

	Thank you.

Best regards,
Hu Ziji

> Yours,
> Linus Walleij
> --
> To unsubscribe from this list: send the line "unsubscribe linux-mmc" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>