How does Live's CPU meter relate to the actual CPU of the pc

elektrovert · Post by **elektrovert** » Wed Jun 27, 2007 1:15 pm

Hi there,

I just noticed with Live 6 the other day that when the meter in live was running between 90%-100% (jumping like mental!) and all I'm hearing is crackleing, that the CPU meter in the task manager is only around 60%

is this normal?

it's a bit annoying, since it appears in the task manager that I've 40% free, yet live is giving me problems.

testube · Post by **testube** » Thu Jun 28, 2007 8:03 am

I'm seeing exactly the opposite...20-40% in Live but 90 to 100% in task manager.

elektrovert · Post by **elektrovert** » Thu Jun 28, 2007 8:43 am

weird.

I'm working throught the manual trying to figure it out but I've got nothing so far.

Homebelly · Post by **Homebelly** » Thu Jun 28, 2007 9:27 am

I think i read some place that the two are not related.
The CPU indicator in Live, or any application for that matter, will only display what CPU % the application is using of the available CPU cycles after the main OS has acquired enough for it's needs,,if your looking at the CPU meter in LIVE and it say's 60%,, that is only an indication that it is using 60% of what it has available,, not 60% of the entire CPU.
this is why it isn't a good idea to have lots of native applications open while you are running a big application such as Logic, live or any audio/video software.
At least,, thats how i understand it.

kettensaege · Post by **kettensaege** » Thu Jun 28, 2007 10:46 am

one other possibility is that the CPU meter displays the ratio between available and used time for the last block calculation. For example, if an audio app is producing audio at 44.1 kHz mono and sending blocks of 1024 samples to an otherwise unbuffered audio interface, the following block would be allowed to take at most 1024/44100 = approx. 23 msec cpu time. If the calculation time for the following 1024 samples is 5 msec, the current load in percent would be (5/23) * 100 = 21.74 %
That would also mean that the audio "CPU" meter is only indirectly related to the system cpu meter and more affected by audio subsystem/driver quality (how large is the comunication overhead to the audio interface?) and process scheduling (is the audio generating process really treated best by the OS or is other stuff interfering?).
just my 0.02$, haven't tried to mesure myself yet

Tarekith · Post by **Tarekith** » Thu Jun 28, 2007 11:09 am

Wasn't it posted once that the meter in Live is actually a disk access meter, and not a CPU meter? Would love a clarification on this as well.

elektrovert · Post by **elektrovert** » Thu Jun 28, 2007 1:08 pm

if that was the case wouldn't the meter be low if you load everything into RAM?

stallos · Post by **stallos** » Thu Jun 28, 2007 1:21 pm

this is what it says in the manual about it page 358

this is something I'm worried about as I've got a gig tonight and last night my lappie kept bouncing around between 30-58%. Was getting some glitching on launching clips which I dont want tonight. The set isnt too intense in terms of FX so dont know whats happenin - buffer set at 512.

gonna try loadin into RAM but what happens if you over load ram?

maual bit

The Control Bar’s CPU meter displays how much of the computer’s computational potential is
currently being used. For example, if the displayed percentage is 10 percent, the computer
is just coasting along. If the percentage is 100 percent, the processing is being maxed
out it’s likely that you will hear gaps, clicks or other audio problems. Note that the CPU
meter takes into account only the load from processing audio, not other tasks the computer
performs (e.g., managing Live’s user interface).
Audio calculations have the highest priority in Live. Therefore, even if the CPU shows a high
percentage of processor usage, the audio stream should remain uninterrupted. However,
non-critical functions (such as screen redraws) might slow down because these tasks are
handled only when the audio processing lightens up a bit.

elektrovert · Post by **elektrovert** » Thu Jun 28, 2007 2:49 pm

Interesting.

So when I'm running stuff like MIDIox in the background then that's gonna make the Live "CPU" meter seem to run higher coz there's less processing availabe to use for audio?

nolus · Post by **nolus** » Thu Jun 28, 2007 5:48 pm

Just a thought, but does your p4 have ''hyperthreading" turned on? if so you should disable it in the bios if possible.

Khazul · Post by **Khazul** » Thu Jun 28, 2007 6:13 pm

Another thought - on my dual core PC I find that if I force the CPU affinity to CPU 2, then live run a hell of alot smoother and CPU meter in live is slighly lower.

More usefully I can run live way more stressed at lower latencies and it remains glitch free. In Live preferences I have multi-cpu support disabled as that was causing some problems.

Tarekith · Post by **Tarekith** » Thu Jun 28, 2007 6:32 pm

stallos wrote:this is what it says in the manual about it page 358

The Control Bar’s CPU meter displays how much of the computer’s computational potential is
currently being used. For example, if the displayed percentage is 10 percent, the computer
is just coasting along. If the percentage is 100 percent, the processing is being maxed
out it’s likely that you will hear gaps, clicks or other audio problems....

LOL, try 70%...

Tone Deft · Post by **Tone Deft** » Thu Jun 28, 2007 6:39 pm

Tarekith wrote:
stallos wrote:this is what it says in the manual about it page 358

The Control Bar’s CPU meter displays how much of the computer’s computational potential is
currently being used. For example, if the displayed percentage is 10 percent, the computer
is just coasting along. If the percentage is 100 percent, the processing is being maxed
out it’s likely that you will hear gaps, clicks or other audio problems....
LOL, try 70%...

If you're getting clicks at 70% what all this is telling me is that your DAW has 30% of crap running in the background.

mikemc · Post by **mikemc** » Thu Jun 28, 2007 7:34 pm

Tone Deft wrote:
Tarekith wrote:
stallos wrote:this is what it says in the manual about it page 358

The Control Bar’s CPU meter displays how much of the computer’s computational potential is
currently being used. For example, if the displayed percentage is 10 percent, the computer
is just coasting along. If the percentage is 100 percent, the processing is being maxed
out it’s likely that you will hear gaps, clicks or other audio problems....
LOL, try 70%...
If you're getting clicks at 70% what all this is telling me is that your DAW has 30% of crap running in the background.

Right, a while back there was a thread that asked at what point on Live's CPU meter do people begin to hear clicks/pops, and a lot of people said 70%.

I recall it is Live's CPU usage over and above other system use (that is, the CPU available to Live). On Windows, if you look at the task manager performance meter, and at Live's CPU meter, you will start to hear problems around the times that the two add up to 100%

elektrovert · Post by **elektrovert** » Thu Jun 28, 2007 9:04 pm

nolus wrote:Just a thought, but does your p4 have ''hyperthreading" turned on? if so you should disable it in the bios if possible.

yes it does.

is that a problem yeah?