Re: [patch] Real-Time Preemption, -RT-2.6.10-rc2-mm3-V0.7.32-15

From: Ingo Molnar
Date: Mon Dec 13 2004 - 18:01:21 EST



* Mark_H_Johnson@xxxxxxxxxxxx <Mark_H_Johnson@xxxxxxxxxxxx> wrote:

> A comparison of PREEMPT_RT (no tracing) to PREEMPT_DESKTOP
> (with tracing) to help answer previous requests.
>
> Comparison of .32-20RT and .32-18PK results
> 20RT has PREEMPT_RT (all tracing disabled)
> 18PK has PREEMPT_DESKTOP and no threaded IRQ's (tracing enabled)
> 2.4 has lowlat + preempt patches applied
>
> within 100 usec
> CPU loop (%) Elapsed Time (sec) 2.4
> Test RT PK RT PK | CPU Elapsed
> X 99.87 100.00& 65 * 64+ | 97.20 70
> top 99.35 100.00& 31 * 31+ | 97.48 29
> neto 96.94 100.00& 113 * 184+ | 96.23 36
> neti 97.05 100.00& 119 * 170+ | 95.86 41

interesting - the PK kernel with tracing enabled performs better than
the PK kernel with tracing disabled? Sounds counter-intuitive.

Ingo
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