Re: [RFC] IO scheduler based IO controller V9

From: Gui Jianfeng
Date: Tue Sep 01 2009 - 21:00:13 EST

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.
> 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%

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