[dm-devel] Re: [RFC] IO scheduler based IO controller V9

[Gui Jianfeng <guijianfeng cn fujitsu com>]

Vivek Goyal wrote:
> Hi All,
> 
> Here is the V9 of the IO controller patches generated on top of 2.6.31-rc7.
> 
> For ease of patching, a consolidated patch is available here.
> 
> http://people.redhat.com/~vgoyal/io-controller/io-scheduler-based-io-controller-v9.patch
> 
> Changes from V8
> ===============
> - Implemented bdi like congestion semantics for io group also. Now once an
>   io group gets congested, we don't clear the congestion flag until number
>   of requests goes below nr_congestion_off.
> 
>   This helps in getting rid of Buffered write performance regression we
>   were observing with io controller patches.
> 
>   Gui, can you please test it and see if this version is better in terms
>   of your buffered write tests.

Hi Vivek,

Here are some performance numbers generated by fio test. It seems V9 performance is better
than V8 especially for write case.

                         Normal Read  |  Random Read  |  Normal Write  |  Random Write

V8(Avg of 3 timers)      64667 KiB/s     3387 KiB/s      59197 KiB/s      9327 KiB/s 

V9(Avg of 3 timers)      65947 KiB/s     3528 KiB/s      61654 KiB/s      9744 KiB/s

Performance              +2.0%           +4.1%           +4.2%            +4.5%