Re: [PATCH] latency improvements, one reschedule moved

[Roger Larsson <roger.larsson@norran.net>]

Hi Linus,

Cleaned up and corrected some bugs...
(memory_pressure... !
 unintended reschedule removed)

Sadly the performance went down - slightly.
Latency looks even nicer. Still some spikes.
[sync and mmap002 behaviour not corrected]

/RogerL



Roger Larsson wrote:
> 
> Hi Linus,
> 
> [patch against  linux-2.4.0-test3-pre2]
> 
> I cleaned up kswapd and moved its reschedule point.
> Disk performance is close to the same.
> Latencies have improved a lot (tested with Bennos latencytest)
> 
> * sync is still problematic
> * mmap002 (Quintinela) still gives a 212 ms latency
>   (compared to 423 ms for the unpatched...)
> * other disk related latencies are down under 30 ms.
>   (streaming read, copy, write)
> * the number of overruns has dropped considerably!
>   (running 4 buffers with a deadline of 23 ms)
> 
> /RogerL
> 
> --
> Home page:
>   http://www.norran.net/nra02596/
> 
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>                                           Encoding: 7bit

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