Can you limit CPU usage for Avisynth in non-MT?

[VideoFanatic]

When I encode 2 720p videos at once in Non-MT I only get 55% CPU usage. When I encode 2 1080i videos at once the CPU usage is 100% which causes my browser to become very slow to use. Is there any way to limit the CPU usage of Avisynth in non-MT?

[ndjamena]

Set it to low priority and you won't have to.

[Baldrick]

Have you tried change the process priority with the task manager? Under Processes right click on the process and set Priority->low.

[jagabo]

You can also launch the encoder with low priority from a batch file so you don't have to use Task Manager:

start /b /low \path\to\program.exe [arguments...]

I use this with x264 CLI all the time:

start /b /low x264.exe --preset=slow --tune=film --crf=18 --sar=10:11 --output %1.mkv %1

I just drag/drop an AVS script onto the batch file. Or put the batch file in my SendTo folder which allows one to right click on an AVS script and select Send To -> filename.bat.

[VideoFanatic]

Thanks it seems to be working now.

[VideoFanatic]

It was working for a while but now it's not. CPU usage is 98% max but my browser is still slow (I've got 100 tabs open) yet Firefox with only a few tabs open is still fast. There's still half a gig RAM not being used.

[newpball]

It was working for a while but now it's not. CPU usage is 98% max but my browser is still slow (I've got 100 tabs open) yet Firefox with only a few tabs open is still fast. There's still half a gig RAM not being used.

What hardware and how many cores do you have?

In Windows apart from setting the process priority you can also restrict the number of cores for a process.

[VideoFanatic]

Core i7 2700K overclocked to 4.2Ghz (4 cores seen by Windows as 8 cores). 8GB Ram. As soon as the encodings finish my slow browser is fast again. It's just a big strange that the CPU usage wasn't even 100% yet during the encodings yet the browser was still slowed even though I set the process priority for the encodings to low.

[newpball]

Core i7 2700K overclocked to 4.2Ghz (4 cores seen by Windows as 8 cores). 8GB Ram. As soon as the encodings finish my slow browser is fast again. It's just a big strange that the CPU usage wasn't even 100% yet during the encodings yet the browser was still slowed even though I set the process priority for the encodings to low.

So you could try to allocate three cores to the process and leave one for browsing.

[ndjamena]

Or you could try setting the IO priority to low as well.

[VideoFanatic]

Setting MeGUI to Low Priority improves a little but it's still slow. How do I allocate less cores to the encoding (I'm NOT using Avisynth Multi-Threaded)?

[poisondeathray]

Set the processor affinity . e.g. don't allow specific cores to use x264 or megui

[jagabo]

It was working for a while but now it's not. CPU usage is 98% max but my browser is still slow (I've got 100 tabs open) yet Firefox with only a few tabs open is still fast. There's still half a gig RAM not being used.

You didn't set your browser to low priority too, did you?

[VideoFanatic]

No I didn't.

Set the processor affinity . e.g. don't allow specific cores to use x264 or megui

How do I do that? I'm using MeGUI.

[poisondeathray]

Set the processor affinity . e.g. don't allow specific cores to use x264 or megui

How do I do that? I'm using MeGUI.

There are utilities to do this, but you can just as easily set it in taskmanager. Google "processor affinity" . Basically you checkmark or uncheckmark which cores you want to use which programs

[poisondeathray]

Not that it's any of my business, but why would you have 100 tabs open in a browser ?

[VideoFanatic]

Not that it's any of my business, but why would you have 100 tabs open in a browser ?

I have my fingers in many pies...

This is weird. When CPU usage is around 100% due to encoding 2 1080i files at once I used speedtest.net in Firefox with no other tabs open (this browser doesn't have slowdown) and it reported my download and upload speed was HALF what it should be. When encoding 2 720 files my cpu usage is around 70-80% and speedtest.net is normal.

Why would a high CPU usage effect the download and upload speed? It's a bit annoying as I'm using my local network connection to transfer recordings from another PC in my house and the upload speed is half on that so it takes twice as long to transfer a file. I think I'm just going to do my 1080i encodings at night when I don't use my PC.

[ndjamena]

It would overload the memory/IO bandwidths which would slow everything.

[jagabo]

Why would a high CPU usage effect the download and upload speed?

Because network download isn't purely I/O. It requires some CPU too. But with encoders running at low priority they should have almost no effect on processes running at normal priority -- the low priority tasks only get CPU time when no other process wants it.

Another possible cause would be virtual memory thrashing. Once that starts happening performance can drop drastically.