[dm-devel] Re: [RFC] IO scheduler based IO controller V6

[Gui Jianfeng <guijianfeng cn fujitsu com>]

Vivek Goyal wrote:
> On Mon, Jul 27, 2009 at 10:10:34AM +0800, Gui Jianfeng wrote:
>> Hi，
>>
>> Here are some fio test results for IO Controller V6 built and not built.
>> Iozone test results are also attached.
>>
> 
> Hi Gui,
> 
> Thanks a lot for some performance numbers. It seems to be a mixed chart.
> Performance gains at some places and loss at others. I am curious about
> that -7.0% for normal writes. Not sure what can contribute to that.
> 
> What was the value of "fairness" parameter when you ran those tests? Can you
> please set fairness = 0 and re-run the tests (if you have already not done so).
> 
> By default fairness is set to 1 in V6. With fairness = 0, we should be very
> close to existing CFQ behavior. If not, then we need to dive deeper and
> see why variations are happening.

  Hi Vivek,

  I re-run the fio test under V6 for normal reads and writes with fairness == 0.
  It seems the performance gets a little better for normal writes than before.
  

  Mode                    Normal read   |   Random read   |   Normal write   |   Random write

  2.6.31-rc1              53,547KiB/s       2,894KiB/s        44,088KiB/s        8,450KiB/s

  V6(fairness = 0)        53,199KiB/s       2,847KiB/s        41,898KiB/s        8,582KiB/s

  Performance		  0%		    -1.6%             -4.9%		 +1.5%

> 
> Is it also possible to run the same tests with V7. 
> 
> Thanks
> Vivek
> 
>> Arch: X86
>> Mem:  1G
>> Disk: 320G
>> IO Scheduler: CFQ
>>
>> ============
>> By normal read and write syscall.
>>
>> Block Size:32K
>> File Size: 1G * 10
>>
>> Mode                    Normal read   |   Random read   |   Normal write   |   Random write | Direct read | Direct write
>>
>> 2.6.31-rc1              47,932KiB/s       3,566KiB/s        45,693KiB/s        8,501KiB/s     50,088KiB/s   43,473KiB/s
>>
>> 2.6.31-rc1-Vivek-V6     47,231KiB/s       3,411KiB/s        42,451KiB/s        8,714KiB/s     51,284KiB/s   42,341KiB/s
>>
>> Performance             -1.5%             -4.4%             -7.0%              +2.5%          +2.4%         -2.6%
>>
>> ============
>>
>> By mmap.
>>
>> Block Size:32K
>> File Size: 500M
>>
>> Mode                    Normal read   |   Random read   |   Normal write   |   Random write
>>
>> 2.6.31-rc1              49,951KiB/s       3,245KiB/s        21,950KiB/s        2,771KiB/s
>>
>> 2.6.31-rc1-Vivek-V6     49,951KiB/s       3,154KiB/s        22,593KiB/s        2,648KiB/s
>>
>> Performance             0%                -2.8%             +2.9%              -4.4%
>>
>> ============
>>  
>> By libaio calls
>>
>> Block Size:32K
>> File Size: 500M
>>
>> Mode                    Normal read   |  Random read   |   Normal write   |   Random write
>>
>> 2.6.31-rc1              49,447KiB/s       3,296KiB/s        57,519KiB/s        21,093KiB/s
>>
>> 2.6.31-rc1-Vivek-V6     50,142KiB/s       3,238KiB/s        57,791KiB/s        21,283KiB/s
>>
>> Performance             +1.4%             -1.8%             0%                 +0.1%
>>
>> ============
>>
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-- 
Regards
Gui Jianfeng