Subject: Re: [linux-audio-dev] POSIX clocks now in linux 2.5
From: Fons Adriaensen (fons.adriaensen_AT_alcatel.be)
Date: Tue Mar 04 2003 - 10:55:01 EET
Paul Davis writes:
> the kernel gives non-SCHED_FIFO/RR threads roughly 1/HZ
> resolution.
Seems to be 20 ms on my unpatched standard SuSE 2.4.19.
I imagine this can be lowered by modifying the kernel config ?
> SCHED_FIFO/RR threads can get better than that if the
> delay is very small, but its implemented by spinning on the
> processor.
Yes, in my first test I used something like 150 microseconds,
and the machine froze for 15 seconds (100000 iterations).
> the new code will provide usec resolution without spinning. it
> reprograms the APIC timer to interrupt the CPU at the right time. i
> believe that you will still need capabilities, euid=0 and/or
> SCHED_FIFO/RR to use it fully.
No problem with that.
TNX for the info.
-- FA
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