Re: [PATCH v5 2/2] mmc: core: Support packed command for eMMC4.5 device

[Saugata Das]

Hi Merez

On 2 March 2012 19:56,  <merez@xxxxxxxxxxxxxx> wrote:
> Hi,
>
> Our tests showed that the write packing improved the performance of the
> write sequential operations:
>
> Long write operation:
> ----------------------
> no-packing: 15.8 MB/s
> packed commands patch (both READ and WRITE packing are enabled): 23.3 MB/s
>
> Several parallel write operations (sum of all the write throughputs):
> ---------------------------
> no-packing: 17.1 MB/s
> packed commands patch(both READ and WRITE packing are enabled): 25 MB/s
>
> Parallel long read and long write operations (write throughput):
> -----------------------------------------------------------------
> no-packing: 12.2 MB/s
> packed commands patch (both READ and WRITE packing are enabled): 16.3 MB/s
>
> Parallel short read and long write operations (write throughput):
> -----------------------------------------------------------------
> no-packing: 15.4 MB/s
> packed commands patch (both READ and WRITE packing are enabled): 16.4 MB/s
>
> Several Parallel short read and short write operations (sum of all the
> write throughputs):
> --------------------------------------------------------------------------
> no-packing: 12.5 MB/s
> packed commands patch (both READ and WRITE packing are enabled): 15.5 MB/s
>

How did you perform the above tests ?

>
> Random read and random write:
> ------------------------------
> I checked the random read and random write IOPs by using the IOZONE
> application. There was a slight degradation in the read results due to the
> packing and no improvements in the write results.
>
> The results are:
>
> IOZONE file size of 100M:
> no-packing: random read: 4675, random write: 729
> packed commands patch (both READ and WRITE packing are enabled): random
> read: 4557 random write: 723
>
> IOZONE file size of 256M:
> no-packing: random read: 4632, random write: 744
> packed commands patch (both READ and WRITE packing are enabled): random
> read: 4498, random write: 742
>
> Thanks,
> Maya Erez
> Consultant for Qualcomm Innovation Center, Inc.
> Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum
>
>> Hi. merez.
>>
>> Would you share random read speed with us ?
>>
>> And Write speed also..
>>
>> Thanks.
>>
>> 2012/3/1  <merez@xxxxxxxxxxxxxx>:
>>>> This patch supports packed command of eMMC4.5 device.
>>>> Several reads(or writes) can be grouped in packed command
>>>> and all data of the individual commands can be sent in a
>>>> single transfer on the bus.
>>>>
>>>> Signed-off-by: Seungwon Jeon <tgih.jun@xxxxxxxxxxx>
>>>> ---
>>>>  drivers/mmc/card/block.c   |  496
>>>> +++++++++++++++++++++++++++++++++++++++++--
>>>>  drivers/mmc/card/queue.c   |   48 ++++-
>>>>  drivers/mmc/card/queue.h   |   13 ++
>>>>  drivers/mmc/core/mmc_ops.c |    1 +
>>>>  include/linux/mmc/core.h   |    4 +
>>>>  5 files changed, 535 insertions(+), 27 deletions(-)
>>>>
>>> Hi,
>>>
>>> We ran performance tests on the packed commands patch. We found out that
>>> enabling the read packing didn't improve the performance in any of the
>>> scenarios we ran (see the detailed results below).
>>> Therefore, we suggest to move the read packing code to a different patch
>>> and approve only the write packing code for now. The read packing adds
>>> complexity to the code and we don't see a point in adding it while the
>>> intention is to disable it.
>>>
>>> Test results:
>>>
>>> Long read operation:
>>> ----------------------
>>> no-packing: 39.5 MB/s
>>> packed commands patch (both READ and WRITE packing are enabled): 39.5
>>> MB/s
>>> packed commands patch + enabling only READ packing: 39.5 MB/s
>>>
>>> Several parallel read operations (sum of all the read throughputs):
>>> ---------------------------
>>> no-packing: 42.6 MB/s
>>> packed commands patch(both READ and WRITE packing are enabled): 38 MB/s
>>> packed commands patch + enabling only READ packing: 38.2 MB/s
>>>
>>> Parallel long read and long write operations (read throughput):
>>> -----------------------------------------------------------------
>>> no-packing: 23.8 MB/s
>>> packed commands patch (both READ and WRITE packing are enabled): 12.6
>>> MB/s
>>> packed commands patch + enabling only READ packing: 12.5 MB/s
>>>
>>> Parallel short read and long write operations (read throughput):
>>> -----------------------------------------------------------------
>>> no-packing: 22.9 MB/s
>>> packed commands patch (both READ and WRITE packing are enabled): 8.4
>>> MB/s
>>> packed commands patch + enabling only READ packing: 8.6 MB/s
>>>
>>> Several Parallel short read and short write operations (sum of all the
>>> read throughputs):
>>> --------------------------------------------------------------------------
>>> no-packing: 41.6 MB/s
>>> packed commands patch (both READ and WRITE packing are enabled): 35 MB/s
>>> packed commands patch + enabling only READ packing: 36 MB/s
>>>
>>> Thanks,
>>> Maya Erez
>>> Consultant for Qualcomm Innovation Center, Inc.
>>> Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum
>>>
>>>
>>>
>>>
>>>
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>
>
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