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

[Vivek Goyal <vgoyal redhat com>]

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.

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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