Re: [LAU] Linux mint for audio?

On 2/18/19 6:10 AM, Len Ovens wrote:
> On Sun, 17 Feb 2019, david wrote:
>
>> On 2/17/19 1:01 PM, Len Ovens wrote:
>>> - no hyperthread
>>> - etc.
>>
>> Yet on my i7 laptop, audio works with hyperthreading just fine.
>
> My experience is that HT is ok at 64/2 but starts to have problems at
> lower latency. This doesn't matter for most recording where the audio
> can be run at 1024/2 but when using the computer as a live synth or
> guitar effects unit, it matters. My general thought is that if something
> matters at a lower latency... sooner or later it will bite with a
> "stray" xrun even at a higher latency.

Can't do 64/2 with my USB card. 512/3 on a non-RT kernel runs at 10.7ms
with no xruns.

>> It is in performance mode, though. I think keeping a steady clock is
>> more important for RT audio than the number of threads.
>
> In recent intel chips with "Boost",

Mine is old enough it has no Boost settings of any sort. Can't be
overclocked, either. Runs at 2.4GHz max. Under heavy loads - not when
doing audio stuff, but when stitching big panoramas - it heats up a lot.

> Performance mode means set the cpu
> speed to rated speed. However, at higher cpu use the speed will still go
> up and down between the limmits of rated speed and max boost speed.
> Going up does not seem to be a problem, but going down does. Also, Boost
> is temperature controlled... this means that the cpu is running closer
> to the maximum temperature and if it gets too close the speed will go
> below rated speed to cool down. Temperature control uses cpu time... but
> the code is not controlled by the OS and over temperature events tend to
> do bad things to audio.

I think temperature is the biggest performance problem on laptops.

> So it is worth turning Boost off to give a
> steady clock frequency. (I have in the past found that setting speed to
> 800Mhz does better audio than "ondemand" at 1.6Ghz) By watching
> temperatures while running the cpu(s) at 100% (build Ardour for example)
> I have found that I could actually run at a higher speed than
> preformance by setting min/max speeds rither than a governor. However, I
> don't do this because I know that things like dust and wearing fans will
> change this over time and rated speed does give some headroom.
>
> Anyway, I set jack to 16/2 and tweak for (hopefully) no xruns or best
> case. Then I am pretty sure I have done the best I can do at higher
> latency. (I turn cron off too while recording) I have a PCI audio
> device, USB devices will not do 16/2... 16/3 maybe, probably 32/* is a
> better target for USB.

Thanks, will keep that in mind. I have a Presonus Firewire card around
that I'd like to connect into the setup. (My old laptop had a Firewire
port.)

My good old reliable motherboard in my desktop machine decided that
being six years old meant it was time for the onboard video to die. I
was using the onboard video because the added video card had also died a
few years ago. (I also switched to a KVM that used USB connections, and
the old BIOS in the machine only recognizes keyboards plugged into the
PS/2 port.) So I'm looking into Ryzen 2700x/mobo/memory combos while the
desktop machine now does reliable work with a 3GHz Pentium.

-- 
David W. Jones
gnome@hawaii.rr.com
authenticity, honesty, community
http://dancingtreefrog.com
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