2011/10/1 Andrei E. Warkentin <andrey.warkentin@xxxxxxxxx>:
> Hi,
>
> 2011/9/28 Barry Song <Barry.Song@xxxxxxx>:
>> From: Barry Song <Baohua.Song@xxxxxxx>
>>
>> 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.Song@xxxxxxx>
>> ---
>
> 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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