RE: [RFC/PATCH 0/2] ROW scheduling Algorithm

[Seungwon Jeon <tgih.jun@samsung.com>]

On Thursday, August 09, 2012 2:06 PM, Tanya Brokhman <tlinder@codeaurora.org> wrote:
Thank you for interesting patch.
Here is other test result.

* Test environment
kernel version: 3.4
Underline device driver: mmc
Host controller: dw_mmc
Card:standard emmc NAND flash

* lmdd with parallel read and write
/data/lmdd if=internal of=/data/writefile bs=128k count=3000
/data/lmdd if=/data/readfile of=internal bs=128k count=3000
		READ		WRITE
CFQ		37MB		23MB
ROW		41MB		23MB

* iozone with parallel read and write
/data/iozone -i0 -r4096k -s200m -I -e -w -f/data/write
/data/iozone -i1 -r4096k -s200m -I -e -f/data/read
		READ		WRITE
CFQ		23MB		24MB
ROW		40MB		17MB

Results show that read throughput of ROW is better than CFQ.
However, write throughput is degraded in case of IOZONE test.
Depending on user scenario, write can be considered to be important.
It needs to check the starvation of write.

Thanks,
Seungwon Jeon

> Hi Chung
> 
> 
> > The below is my environment:
> > Kernel Version: linux-3.4
> > Card: eMMC4.5 (50MHz DDR mode, 8-bit buswidth) Host controller : dw-
> > mmc (DesignWare MMC controller) Benchmark : IOzone
> >
> > *CFQ Scheduler
> > Read : 35MB
> > Write : 17MB
> >
> > *ROW Scheduler
> > Read : 28MB
> > Write : 17MB
> >
> > How do you think about this result?
> >
> 
> I run your cmd of iozone on my setup and got a bit different results:
> CFQ scheduler:
>           204800   16384   27903   27248    40345    40399
> READ:	40   MB/sec 		WRITE: 27   MB/sec
> 
> ROW scheduler:
> READ:	39.6 MB/sec		WRITE: 27MB/sec
> 
> As you can see the results are the same for both schedulers.
> Anyway, the improvement added by ROW is in scenario of parallel read and write, which iozone doesn't
> do so running iozone for comparing ROW to CFQ is useless.
> If it's not too difficult I would appreciate if you could run the bellow 2 commands simultaneously on
> your setup:
> adb shell /data/lmdd if=internal of=/data/writefile bs=128k count=3000
> adb shell /data/lmdd if=/data/readfile of=internal bs=128k count=3000
> You'll see an improvement in throughput when using ROW over CFQ.
> We have a patch that also measures latency and we saw that read latency was also improved greatly when
> using ROW.
> 
> 
> Thanks,
> Tanya Brokhman
> ---
> Sent by an consultant of the Qualcomm Innovation Center, Inc.
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.
> 
> 
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