The difference between Live's CPU meter and Task Manager

southernsteppa · Post by **southernsteppa** » Tue Mar 20, 2007 7:13 am

I'm sure I read about this somewhere before, but digging through the forums hasn't given me any results...

I have a project that contains quite a few internal routings and automated dummy clips for quad panning via sends. When I am generally working on this set, there are no problems. It isn't plug-in heavy, nor are there a billion scenes or clips in there. However, once I hit play and the dummy clips start doing their thing, Live really seems to be struggling.

When I open the project initially the Live CPU meter reads at around 1-2% (once stopped and idling, it stays firmly at 13%). When I hit play it jumps to around 30% and then up to 50% once it really gets going. This isn't usually a problem for my computer when the meter gives these readings. But for this particular set, the GUI starts getting really jumpy and changing windows or doing any other tasks gets frustratingly slow.

So after checking Windows Task Manager, it tells me that Ableton is using anything between 60-90% CPU!

So what exactly is going on here? I'm not getting audio dropouts as yet, but obviously Live is having a hard time with routing this amount of audio. And it's not being reflected in the CPU meter.

My setup if you need some more info: P2.8Ghz, 2GB RAM, Firewire 410, Live 6.0.5

justin · Post by **justin** » Tue Mar 20, 2007 10:06 am

i seem to remember that live's cpu meter only polls live's dsp processes. i dont think this includes graphic or other os processes in the background... which explains the difference between the task manager and live's meter, and it probably also explains why ur graphic redraw time is so slow.

j

southernsteppa · Post by **southernsteppa** » Tue Mar 20, 2007 12:08 pm

Yep, I think you're right. But Task Manager was telling me that Ableton specifically was using 90% CPU - not the total for everything I have running. That was maxing out to 100%. I don't see Live's GUI accounting for a doubling of CPU usage.

justin · Post by **justin** » Tue Mar 20, 2007 2:27 pm

it's probably not just the gui, there are also various memory processes, hard disk access etc... then of course, you have to add a few bits of buggy code ; )

however, it does sound quite high considering the description of what u are doing with the software... maybe u should compare the set on another system/computer?

southernsteppa · Post by **southernsteppa** » Tue Mar 20, 2007 8:55 pm

That's probably a good idea. I'll see what I can do over the next couple of days and post any results.

Thanks for your suggestions.

southernsteppa · Post by **southernsteppa** » Thu Mar 22, 2007 9:29 pm

I installed Live and my project on a PowerBook G4 and didn't have much luck.

Idling CPU usage is much the same, however it really struggles to play the set once I start triggering midi (have have Sampler triggered by a padKontrol). I'm not particularly familiar with Mac's, so I don't know how the specs of this G4 should stack up against my PC. I did notice that clicking the cursor around in the arrangement view didn't cause any problems like it does on my PC though.

So, I went back to my PC and started to remove pieces of my set to see if there was any change. Removing warped clips made no difference, nor did deleting all the automated dummy clip tracks and the returns. So I was left with similar CPU usage on just 9 tracks, with no clips - just racked instances of Sampler.

Then I decided to delete some of the reverb I have on tracks - there are quite a few chains with Live's reverb and GlaceVerb in there - pretty much straight away it made a big difference to the CPU meter. And this was a meter reading from the Live set when it is idle. Could this suggest Live is monitoring reverb even when it's not in use?

I've also mentioned this issue here: http://www.ableton.com/forum/viewtopic.php?t=60621

Edit: deleting all the reverb from the project on the G4 also changed idle CPU usage from 10% to 1%.

justin · Post by **justin** » Thu Mar 29, 2007 2:18 pm

i believe live is supposed to poll fx like reverb until they have finished their trail of sound. of course, this is only really applicable to fx which produce sound after the original signal has decayed (eg. reverb, delays, etc...)

but i am not a big fan of the live reverb, dont really like the sound that much and it's quite cpu hungry. have u tried with just third party reverbs? having said that i havent noticed any problem with live's reverb on my macbook pro.

u might also want to try to unrack your samplers + effects to see if the root problem of the problem is with the fx cpu hit or because these fx are in racks.

j

anti-banausic · Post by **anti-banausic** » Thu Mar 29, 2007 4:03 pm

southernsteppa wrote:I installed Live and my project on a PowerBook G4 and didn't have much luck.

Idling CPU usage is much the same, however it really struggles to play the set once I start triggering midi (have have Sampler triggered by a padKontrol). I'm not particularly familiar with Mac's, so I don't know how the specs of this G4 should stack up against my PC. I did notice that clicking the cursor around in the arrangement view didn't cause any problems like it does on my PC though.

So, I went back to my PC and started to remove pieces of my set to see if there was any change. Removing warped clips made no difference, nor did deleting all the automated dummy clip tracks and the returns. So I was left with similar CPU usage on just 9 tracks, with no clips - just racked instances of Sampler.

Then I decided to delete some of the reverb I have on tracks - there are quite a few chains with Live's reverb and GlaceVerb in there - pretty much straight away it made a big difference to the CPU meter. And this was a meter reading from the Live set when it is idle. Could this suggest Live is monitoring reverb even when it's not in use?

I've also mentioned this issue here: http://www.ableton.com/forum/viewtopic.php?t=60621

Edit: deleting all the reverb from the project on the G4 also changed idle CPU usage from 10% to 1%.

You may need to check and see if Glaceverb is giving you a problem. It suffers from the denormalization problem on P4 processore. Basically, after it stops processing audio, it will continue to run, sometimes at a greater degree than previously, because it is trying to do calculations on very small bits of information that are not stopped on P4 processors. I used to use glaceverb on my P4 PC, and it could be annoying at times. There is a plug in that will halt the stream of data to glaceverb, I found it over at KVR, but I forget what it was, "normalizer" or something like that.

You should probably definitely check if that is the culprit.

Best,
AB

southernsteppa · Post by **southernsteppa** » Fri Mar 30, 2007 5:55 am

Thanks for the tips. I had a feeling GlaceVerb was causing a problem and removed it completely. Live's reverb was somewhat better, but I ended up using a single return for all the reverb, even though this wasn't ideal, because I received this response from Ableton support:

Yes, as soon as a effect is in your set, it eats CPU, there´s no way around this.

I have read conflicting opionions about this in the forums - does anyone have much experience with effects consuming CPU without any audio going in/out?

anti-banausic · Post by **anti-banausic** » Fri Mar 30, 2007 6:42 am

southernsteppa wrote:Thanks for the tips. I had a feeling GlaceVerb was causing a problem and removed it completely. Live's reverb was somewhat better, but I ended up using a single return for all the reverb, even though this wasn't ideal, because I received this response from Ableton support:

Yes, as soon as a effect is in your set, it eats CPU, there´s no way around this.
I have read conflicting opionions about this in the forums - does anyone have much experience with effects consuming CPU without any audio going in/out?

That does sound like a strange response, as I believed from early on (LIVE 3) that, at the very least, Ableton effects weren't using CPU unless audio is sent to them. I still believe it, or at least the CPU hit is negligible.

3rd party VSTs, and VSTis are another issue. It seems that some don't use CPU when idle, and some do.

Best,
AB

Still, I would say that depending on the music you are making, having a reverb on a send is a good idea. You can control the amount of each track that is sent to it, but it should help everything gel in one space. However, this could be more important for more traditional music (rock, jazz, etc...), not sure about experimental stuff.

southernsteppa · Post by **southernsteppa** » Fri Mar 30, 2007 7:07 am

anti-banausic wrote:Still, I would say that depending on the music you are making, having a reverb on a send is a good idea. You can control the amount of each track that is sent to it, but it should help everything gel in one space. However, this could be more important for more traditional music (rock, jazz, etc...), not sure about experimental stuff.

I generally agree, but this project did fall deep into experimental territory for me. The main thing I was trying to achive was having the reverb "follow" the quad panning - hence reverbs on different tracks and sends.

Thanks again for your replies AB - I might do a bit more testing on Live reverb vs 3rd party reverb and see how I go. I'll post anything I find here.

aeon · Post by **aeon** » Fri Mar 30, 2007 8:52 am

i sometimes get spikes of over 4000% CPU... yes, four thousand percent.

one project i have is hovering at about 2600% CPU constantly.

anti-banausic · Post by **anti-banausic** » Fri Mar 30, 2007 3:08 pm

southernsteppa wrote:
anti-banausic wrote:Still, I would say that depending on the music you are making, having a reverb on a send is a good idea. You can control the amount of each track that is sent to it, but it should help everything gel in one space. However, this could be more important for more traditional music (rock, jazz, etc...), not sure about experimental stuff.
I generally agree, but this project did fall deep into experimental territory for me. The main thing I was trying to achive was having the reverb "follow" the quad panning - hence reverbs on different tracks and sends.

Thanks again for your replies AB - I might do a bit more testing on Live reverb vs 3rd party reverb and see how I go. I'll post anything I find here.

Now that I have a core2duo I might have to look at glaceverb again. It did sound pretty darn good for a freeware app.

There are some good native verbs out there for PC, but they will cost you, like artsacoustic.

Best,
Ab

aeon · Post by **aeon** » Sun Apr 01, 2007 11:05 am

glaceverb can sound really cool...

i still prefer Ambience tho. best freeware reverb by far imho, it just sounds lush!