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

[Vivek Goyal]

On Mon, Jul 27, 2009 at 08:55:03AM -0400, 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.
> 

Gui, can you also try with CONFIG_TRACK_ASYNC_CONTEXT=n and see if it improves
buffered write performance.

Thanks
Vivek

> 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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