Newbie question about slowdown

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Newbie question about slowdown

Postby moviesign » Thu Jun 16, 2011 4:56 pm

Brand new to the Folding@Home universe and I'm having an issue with my setup. I'm on my work machine running 10.5.8 on a dual 2.8 GHz Quad-Core Xeon with 12 GB of RAM. I installed the basic Mac F@H installer as I'm not super-comfortable with the Terminal. Fired up F@H through System Preferences, checked it in Activity Monitor, and saw it was hitting the CPU for about 800, and taking about 700 MB of VM, 90MB of real RAM. That's fine, it's processor intensive. Plenty of other processes take more.

My problem comes when I try to run Photoshop or After Effects to do my job. Both programs are uncomfortably slow. Moving layers in Photoshop has become a stuttering crawl. Manipulating layers in After Effects is almost unworkable. I thought F@H was supposed to automatically scale back on the processor whenever another application needed some juice, but it doesn't seem to be allowing the other programs the overhead they need. I've looked through the FAQs and these forums to see if there's a setting I can adjust or if I'm doing something wrong, but so far, no joy. Maybe the answer's there and I just don't understand it.

Again, sorry for the newbie nature of the question. I'm trying to join the cause, and I'm trying to get my corporation to create a corporate-wide team so we can all contribute, but I need to make sure there won't be any performance hit. I'm sure the vast majority of the folks who are only running things on their PCs like Office or WideOrbit won't even notice the hit, but for the folks in the graphics departments, I need to be sure we can keep plugging along at normal speed. Is this just the nature of the beast with competing processor-hungry applications, or is something not working the way it should?

Thank you all in advance.
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Re: Newbie question about slowdown

Postby 7im » Thu Jun 16, 2011 5:16 pm

Hello moviesign, welcome to the forum and to folding.

The SMP client is a high performance client. It does not scale back like the regular CPU client does. The quick and dirty fix is to change the SMP client setting to use only 6 or 7 of your 8 processors. Adding the "-smp 7" setting will tell the client to only use 7 cores. That should reduce the lag enough to where most programs are workable. However, Photoshop can be a beast, and you may have to back down to 6 cores, depending on how large or complex the images you edit.

Sorry, I haven't been a Mac person since the 7600 PPC, so I'm not much for helping you add that -smp 7 setting. Someone better able to help with that, if needed, will drop by shortly. ;)
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Re: Newbie question about slowdown

Postby moviesign » Thu Jun 16, 2011 5:31 pm

7im,

Thanks for the fast response! Entering the "-smp 7" setting in the Extra Parameters field in the Advanced tab of System Preferences (in case any other Mac users come looking for a solution to this problem) did the trick. F@H is still hitting the CPU plenty hard, but there's now enough overhead for the Adobe Trinity to have their share and work smoothly. I may have to scale down one more core on really huge projects, but knowing I can get some processor cycles back without killing F@H completely is great news. Now to convince my corporate masters that this is a worthy use of their equipment...

Thanks again!
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Re: Newbie question about slowdown

Postby 7im » Thu Jun 16, 2011 5:41 pm

I recommend getting that permission in writing. Yes, that seems rather formal, but if Master 1 approves it, and is later replaced by Master 2, you'll have that piece of paper to help CYA in case Master 2 isn't as understanding. ;)
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Re: Newbie question about slowdown

Postby radekboktor » Fri Jun 17, 2011 5:59 pm

~ Additional details if you care ~

Folding used to be a lot less intrusive, and the fault is actually Apple's. In the early days of OS X it used the same priority control system as the rest of UNIXland, a number attached to each running process called nice. A low nice value meant a process would push its way to be first in line, for instance an audio handler built into the OS might need high priority (because the human ear can perceive really tiny amounts of lag in audio). Whereas something like folding would have a high nice value, and so it would be slowed down when anything "normal" wanted CPU time.

A few years back though, some smart person at Apple said, "Hey, this 'nice' system is really primitive. What should be happening is that the OS should be deciding priority based on what kind of calls each thread within a process is running. For instance, when Safari opens a new window, the window should draw onscreen really fast so the user doesn't perceive lag. But the content of the window is going to take a (relatively) long time to download from the website, so the routines that draw the content can have low priority without making the software feel slower." The nice value is still there, only now it's merely a suggestion to the OS's decision-making process.

So where does that leave us now? Well folding is still treated as a nice process, and the math it does is also treated as fairly low priority by the OS. The trouble is, other math-intensive stuff like converting video, or applying effects in Photoshop, is also treated as low priority. So when you're using Photoshop, the OS is probably giving some chunks of CPU time to PS, but also giving big chunks to folding. Software will still load quickly and things like new windows will spawn fast while folding... but there's no easy way to have folding automatically get idled while you're doing your actual work with PS and AE.

There is an app called Increase that serves as a nice GUI for regular folding. It gives you a pause function, as well as an auto-pause you can set up for when certain apps are running (such as video encoding software). Likewise, the beta folding app (v7 and FAHControl) has a pause feature implemented. These both require active participation by the user though, and so are inappropriate for a general corporate install. My suggestion would be to experiment with smp 7 and smp 6, see whether 6 lets AE run faster than smp 7. After all, if these are work machines, you really don't want any significant slowdown as a result of folding. 8-core machines chew through standard SMP units really fast even with only 6 cores actively folding. Once you figure out which setting makes it truly unobtrusive, then it should be easy to convince the boss that you've got it under control.
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