[PlanetCCRMA] XRUNS and more

[Fernando Lopez-Lezcano]

On 05/13/2016 09:14 AM, Etienne Rouge wrote:
>
> Thanks for the quick reply. I really appreciate !
>
> I run Renoise with vanilla plugins.
>
> - CPU Intel(R) Core(TM) i5-2500 CPU @ (quad 3.30GHz)
> - 16gb ram
>
> It should be more than enough.
>
> I have edited /etc/sysconfig/rtirq  with :
> RTIRQ_NAME_LIST="rtc firewire_ohci" (and haven't touched the rest made
> by rncbc)
>
> I'm not sure it has done anything...

See what priorities you have with "rtirq status"...

> I'll try your script and I'll tell you how it goes.

You have an i5 cpu so you do not have hyperthreading. Don't run the 
examples that I sent blindly, you have to understand what you are doing 
(if you turn off all 4 cores you are left with nothing :-)

-- Fernando


> Le 13/05/2016 à 17:43, Fernando Lopez-Lezcano a écrit :
>> On 05/13/2016 05:15 AM, Etienne Rouge wrote:
>>> Hello,
>>
>> Hi Etienne,
>>
>>> I've recently switched back to CCRMA and I'm rather happy with it.
>>>
>>> However I still have xruns when I really shouldn't (powerfull computer
>>> and reasonnable amount of tracks/effects).
>>>
>>> I've set up PAM…  added "rtc firewire_ohci" to the irq file. Honestly, I
>>> don't quite understand the few tuts I find online and the fact they are
>>> not fedora-oriented don't help.
>>>
>>> Is there a crucial step I've missed ? A tutorial I can follow ?
>>
>> Could you tell us what hardware is this? What software are you
>> running? I presume you are running rtirq and you have access to
>> SCHED_FIFO rt scheduling in your account.
>>
>> I have found that for critical low latency work using recent hardware
>> I need to disable hyperthreading (the fake cores on Intel processors
>> that can't do much) and also set the intel_pstate driver to try to use
>> all cores at high speed. Also disable thermald if you are using it (it
>> could also be throttling the processors). Maybe this would help?
>>
>> I have this in a script I run when needed (this is on a four core
>> Intel laptop with HT):
>>
>> # get all processors to run fast all the time...
>> echo "100" > /sys/devices/system/cpu/intel_pstate/min_perf_pct
>>
>> # turn off hyperthreading which only makes things worse most of the time
>> # we do this by turning off cpus that have the same "proc id"
>> echo 0 > /sys/devices/system/cpu/cpu1/online
>> echo 0 > /sys/devices/system/cpu/cpu3/online
>> echo 0 > /sys/devices/system/cpu/cpu5/online
>> echo 0 > /sys/devices/system/cpu/cpu7/online
>>
>> Best luck! And let us know how it works out...
>> -- Fernando
>>
>
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