Optimizating OSs

[David Scidmore]

This was prompted by something Slackmaster2K said in another thread:

"For that matter, don't ever do ANY "optimizations" unless a) you have an actual need to and b) you can demonstrate that the optimization actually improved performance noticably."

While I can understand and agree with the comment about not messing with the swap file, I am reluctant to brush off all forms of optimization. Most of the suggestions I'vs seen for optimization were aimed at making a non-real-time OS, (i.e. Windows) operate as if it were a real time OS. In other words they have less to do with "outsmarting" programmers and more to do with making sure that normal Windows functions don't unexpectedly kick in in the middle of recording a track.

I occasionally have dropouts in recording MIDI data in Logic Audio. I have plenty of CPU bandwidth, DRAM, disk space, and am using pretty standard equipment. I have yet to track the problem down, but it seem reasonable to me to start with the hypothesis that Logic is getting preempted by interupts or some other task. If that is the case it makes sense to me to me to try such things as eliminating the Maintainance Wizard and Task Schedulure (as 98lite does). This might prevent them from taking over in the middle of trying to record, where even a couple dozen mS of lost CPU time will be clearly audible.

Maybe I'm not understanding Windows correctly, but my understanding was there really is no way for an ap like Logic to prevent other aps or device drivers from taking over at the wrong time, other than making sure the system is "optimized" against it.

 

[Slackmaster2K]

You didn't read enough of my post.

Setting up your hard drives to do DMA, getting your soundcard onto its own IRQ, and so on and so forth... this is a process of configuration. That's how I look at it.

Optimization implies that a system is configured properly, and now we're going to tweak a few things to squeeze out performance.

If your hard drives are not doing DMA, or you've got IRQ problems, etc, then your system is not properly configured.

Both IRQ and DMA issues are covered in optimization FAQs and i have no problem with these sorts of things (though I don't like the term optimization applied to them)....what I do have problems with are people who are start doing all sorts of crazy shit to their system for no reason at all. When you start trying to control everything, without truely understanding the interaction between the various hardware and software components in your system, there's a good chance you're going to screw something up. Hardware and software are rigorously tested on standardly configured machines, and you should try to run your machine in as standard a *configuration* as possible.

Optimizations like turning off video acceleration, screwing with the swapfile, and so on, are silly. Sure you can give em a try if you like, but if you don't notice any substantial performance gain then you should change things back ASAP.

The only optimizations I'd recommend are those recommended by the manufacturer of your SOUNDCARD. For instance the RME FAQ states that in Windows 2000 you should set the system to optimize for background applications to improve ASIO performance. They say it can decrease latency from 20ms to 7ms or something like that. Cool. I tried it with my Delta card however, and performance actually dropped. So, live & learn.

The point is, try everything once for your own piece of mind...then when nothing happens, be sure to change things back.

Slackmaster 2000

 

[pglewis]

Just to tag one more suggestion to what Slack said: make one change at a time if you do decide to tweak things. It's best to know exactly what did what and you can't do that if you apply a gazillion tweaks at once and then try to record.