Re: [PATCH] mmc: sdio: To use multiple scatter gather list

[Chris Ball <cjb@laptop.org>]

Hi,

On Wed, Nov 07 2012, Kyoungil Kim wrote:
> On Tue, Oct 30 2012, Chris Ball wrote:
>> Hi,
>> 
>> On Mon, Oct 22 2012, Kyoungil Kim wrote:
>> > We used only single sg entry for SDIO transfer.
>> > This chagne is to use multiple sg entry.
>> > In case of dwmci, it support only up to 4KB size per single sg entry.
>> > So if we want to transfer more than 4KB, we should send more than
>> > 1 command.
>> > This makes performance degradation for large data transfer.
>> >
>> > Signed-off-by: Kyoungil Kim <ki0351.kim@samsung.com>
>> 
>> Can you share the before/after benchmark on your controller, please?
>
> When we test before apply this patch, it takes around 335 us for
> 5K(5120) bytes transfer with dwmci controller.
> But when we test after apply this patch, it takes 242 us for 5K bytes.
> So this patch makes around 38% performance improvement for 5K bytes transfer.
> If the transfer size is bigger, then the performance improvement ratio
> will be increased.

Thanks, pushed to mmc-next for 3.8.

- Chris.
-- 
Chris Ball   <cjb@laptop.org>   <http://printf.net/>
One Laptop Per Child