Multicore Support ON, but CPU 2 isn't used

arachnaut · Post by **arachnaut** » Sat Apr 07, 2007 9:08 pm

I have a Dual Core Athlon 64 X2 4200+ with Live 6.0.5.

I have multiprocessor support enabled.

Please look at the picture below - it is a screen dump
of my setup running 4 MIDI tracks. It shows the
CPU preferences for Live the AMD CPU monitor and
the Live and Reaktor application windows.

Clearly the second CPU isn't being used, but the
first CPU is maxed out.

I have Reaktor 5.1.2.009 VSTs running in tracks 1, 2, 4 and
Chamelon5000 v1.70 VST running in track 3.

What is happening??
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Amaury · Post by **Amaury** » Sat Apr 07, 2007 9:55 pm

Hi,

Live distributes threads on both processors/cores only from separated track: it is not possible to separate one track's processing, not to separate the calculation of tracks routed in one another. So, if your Reaktor patch is taking 100% CPU, it will max out one of the CPUs.

By the way, you may get a better performance by setting the 'plugin buffer size' to 'same as audio buffer'.

Regards,
Amaury

arachnaut · Post by **arachnaut** » Sat Apr 07, 2007 11:05 pm

Amaury wrote:Hi,

Live distributes threads on both processors/cores only from separated track: it is not possible to separate one track's processing, not to separate the calculation of tracks routed in one another. So, if your Reaktor patch is taking 100% CPU, it will max out one of the CPUs.

By the way, you may get a better performance by setting the 'plugin buffer size' to 'same as audio buffer'.

Regards,
Amaury

I don't understand - there are 4 tracks running here.

The track displayed shows one Reaktor patch using 59% of the CPU.

The other patches are on other tracks contributing to the remainder
of the load.

4 separate tracks all running on 1 CPU.

OK, thanks for the tip on the plug-in size - I set that as you suggest.

sweetjesus · Post by **sweetjesus** » Sun Apr 08, 2007 12:51 pm

maybe the diff channels are all seeing reaktor as one thing due to how the engine of reaktor works.. so anything using reaktor will all be dumped in one cpu

add some non reaktor stuff to your set and see how you go

arachnaut · Post by **arachnaut** » Sun Apr 08, 2007 2:26 pm

sweetjesus wrote:maybe the diff channels are all seeing reaktor as one thing due to how the engine of reaktor works.. so anything using reaktor will all be dumped in one cpu

add some non reaktor stuff to your set and see how you go

That is why I loaded Chameleon (a non-Reaktor VST),
to test this issue.

As each track got assigned a VST instrument or effect, all the resources
were assigned to the same CPU no matter which plug-in I used.

Using Live instruments only, the load is distributed evenly, but
the ReWire stuff doesn't seem to distribute.

Each of the three Reaktor plug-ins is a different ensemble
and some use Reaktor effects (the Reaktor effect plugin
is different than the Reaktor instrument plugin).

The Option field for Multicore support is ON and Green,
the Option for Multicore ReWire is ON but Grey - that is
what I was worried about. And that seems to be the issue.
Shouldn't it be bright green like the other option?

arachnaut · Post by **arachnaut** » Mon Apr 09, 2007 5:20 pm

In a related matter -

When the Audio Test tone is used and CPU load simulation
is on for setting up sample size buffers, etc., the CPU load only
occurs in a single CPU.

arachnaut · Post by **arachnaut** » Tue Apr 10, 2007 1:45 pm

I updated the image to make this clearer.

Refresh your browser image cache if you see a
picture without annotations.

On my system tray are two cpu indicators that
should be clear at the bottom right.

One (AMD Power) shows instantaneous usage
and the other (TaskInfo) shows a histogram.

Both show 50% utilization. The AMD Power monitor
is also maximized and shown over the Live window.

anti-banausic · Post by **anti-banausic** » Tue Apr 10, 2007 2:28 pm

Hi. I am afraid that I can't help you much, but I think that this is not an issue with rewire, as you aren't really using rewire. Unless I am mistaken, this would only be an issue if you were using LIVE as a slave to another sequencer, or were using something like Reason which rewires into LIVE (where LIVE acts as a master). VSTs used within LIVE shouldn't be affected by whether or not the rewire multicore option is grey or not.

Hopefully that allays your concern about that. Again, I could be wrong, but as I understand rewire, it shouldn't be a problem there.

Best,
AB

arachnaut · Post by **arachnaut** » Tue Apr 10, 2007 3:25 pm

All right, I can accept the ReWire explanation for why the ReWire
option is not green. However, the real issue is the cpu load distribution.

Here is an example of the load properly distributed when I use
only Live instruments. This is the Live 5 Performance test Live Set.

You can see that the cpu is loaded evenly and the AMD speed setting
is only 1GHz. It can ratchet up to 1.5 GHz and 2.2 GHz as needed
by the system.

Proper load distribution screen dump:

anti-banausic · Post by **anti-banausic** » Tue Apr 10, 2007 4:14 pm

Have you tried using other third party plugins without using reaktor? Perhaps NI plugs aren't playing nicely, which wouldn't be the first time.

arachnaut · Post by **arachnaut** » Tue Apr 10, 2007 5:15 pm

Well I'll be darned.

Now things work as expected.

I didn't change anything, but now I loaded about
7 or 8 Reaktor plug-ins and the load was distributed evenly.

I can't explain what I saw before.

Is the Live CPU assignment algorithm a round-robbin or least used?

If round-robin, I might have loaded a plug-in, then another,
then deleted one and reloaded in such a way that the same CPU got
selected in the round by chance.