Re: Low-latency patches working GREAT (<2.9ms audio latency), see testresults ,but ISDN troubles

Ingo Molnar (mingo@chiara.csoma.elte.hu)
Sun, 29 Aug 1999 09:22:24 +0200 (CEST)


On Sat, 28 Aug 1999, Benno Senoner wrote:

> - The disk performance decreases by 10-25% when I increase the CPU load
> in the "latencytest" bench. (On light CPU load there are no disk
> performance differences, maybe this is related to higher scheduling
> overhead)

just in case anyone misunderstood the above result (as i think many did).
The 'CPU load' mentioned above is a _realtime process_ (unless Benno you
changed the benchmark). This is a _good_ result. 'increase CPU load'
simply means 'generate more RT load' - which in _this case_ might mean
less disk performance - but the RT task asked for it in the first place.
All in one: i can see no problem here.

if a 'simple' CPU-user (non-RT) is getting more active there is no
slowdown.

-- mingo

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