[linux-audio-user] kernel 2.6.20.1 & rt-patch 2.6.20-rt8

Robin Gareus robin at gareus.org
Wed Mar 7 18:20:57 EST 2007


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Robin Gareus wrote:
> 
> 
> Lee Revell wrote:
>> On 3/7/07, Robin Gareus <robin at gareus.org> wrote:
>>> PS. can anyone shed some light on the CONFIG_NO_HZ option - seems like
>>> it saves quite some power. Does it affect realtime performance. can it
>>> be disabled at runtime?
>>>
>> Should not affect realtime performance - it was judged stable enough
>> for mainline and I've seen no reports on LKML of it causing problems.
> 
>>> PPS. i've usually disabled freq. scaling during audio-work as there were
>>> x-runs when the cpu speed changed. this does no longer seem to be the
>>> case.. is it still a good habit to shut down powernowd ?
>> JACK was fixed to use gettimeofday() as the clock source so disabling
>> frequency scaling should no longer be needed.
> 
> cool. I am already 10 mins into the compiling a tickless kernel (branch
> prediction pipelined it) and will report back if there's trouble!

there are ;-)

well no jackd + ardour work great! low latency, no xruns.. USB -p128 -n2
the system works fine but for suspend (uswsusp) - I have not yet tried
suspend2 or various patches and am back to a preemptive 2.6.18-SMP for
day to day use :(

that yields occasional xruns with -p128 on USB. "-p256 -n 2" plays now
x-run free for 25 mins, but I guess I'm just lucky ;) - the internal
soundcard is crap but ran xrun free with -p64 -n3 on this non-rt patched
 but preemtive 2.6.18.


back to 2.6.20.1: The idle power consumption with CONFIG_NO_HZ is only
slightly less: 13.2W avg - as opposed to 13.8W avg with 2.6.20-rt8 w/o
CONFIG_NO_HZ) (that was with active wireless and display brightness 4/7
, similar conditions.)

Did any of you guys get suspend/hibernate working with a 2.6.20.1-rt8 or
later? :) on a dual-core & intel-945GM that is. - on a related OT issue:
hdaps (acceleration sensor) only reports zero values with both patched
hdaps_protect-2.6.18.3-2 and vanilla 2.6.20.1 - but works fine under
windoof.

cheers,
robin
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