2011/10/1 Andrei E. Warkentin <andrey.warken...@gmail.com>:
> Hi,
>
> 2011/9/28 Barry Song <barry.s...@csr.com>:
>> From: Barry Song <baohua.s...@csr.com>
>>
>> now we wait 1ms after every loop, in the worst case, 1ms will be wasted.
>> that both decreases sd performance and increases cpu usage.
>> This patch shorten the interval to 1us, then in the worst case, only 1us
>> is wasted.
>>
>> Signed-off-by: Barry Song <baohua.s...@csr.com>
>> ---
>
> Cool! How much I/O perf did you gain?

A test was done by bonnie++ on csr prima2 with 2GB class 2 SD card.

before applying this patch:
Version 1.03e       ------Sequential Output------ --Sequential Input- --Random-
                    -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks--
Machine        Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP  /sec %CP
SiRFPrima2     768M  2555  39  2737   0  3661   2  5947  91 13301   3 909.3   4

after applying this patch:
Version 1.03e       ------Sequential Output------ --Sequential Input- --Random-
                    -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks--
Machine        Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP  /sec %CP
SiRFPrima2     768M  2611  40  2668   0  3675   2  5952  91 13302   3 952.2   4

>
> A
> -

-barry
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