Does Fedora automatically use all available cores?

[AdamW]

jongi: no, you don't have to make any special configuration changes.

[diamond_ramsey]

Originally Posted by Jongi

The question related to the fact that in Debian one has to set EXPORT_CONCURRENCY and in Gentoo you have to set MAKEOPTS. So was just wondering if there was a similar setting in Fedora.

Concurrence with AdamW on not having any special configuration changes.

Jongi, I would only add that to make sure that the irqbalance service is running.

I find that the irqbalance service is useful to me.

Hope this helps.

[typerlc]

My computer is running 10 tasks not counting top as I type this.

How did you count those? They have to be in the run queue to be counted.

The easiest way to tell how many are in the run queue is to run this command:

vmstat 1

The first column (heading "procs r" is the number of processes (that second) waiting to be run (or running) i.e. runnable i.e. in the run queue. etc.

Most of the time, my system has 0-4 runnable processes. And I have firefox, terminal, kde, VirtualBox (running windows), OpenOffice, etc. all open at the same time. If I count the number of processes started, there are around 170 currently. Most of them spend most of their time idle.

Of course, everyone does different things with their computer, but in a desktop, typically there aren't that many processes actually competing for cpu time. So lots of cores won't help the majority of users the majority of the time.

[SlowJet]

Well, if you had a pizza crust and only 1 pizza girl, she would take a lot longer to make 4 topping pizza than
4 pizza girls dumbing the topping on at the same time.

If the pizza had to go through several processes and their was a pizza girl at each station, usually the Saturday rush, then one could say they make one pizza instantly.

But if 1 pizza girl had to move the crust down a line and put on more toppings, as usually the case on Monday's, then it will take the pizza girl a longer time to make a pizza.

I don't know about you, but I don't like waiting for my pizza.

SJ

[typerlc]

your analogy is flawed in several ways. A closer, but still flawed analogy is that the 4 girls can each work on one pizza each. So if you get 4 orders in, they'll each work on one pizza in parallel. As you can see they will work faster than 1 girl making all 4, but not 4*faster. There is contention for access to the dough and toppings.

Now, consider you want to speed up your pizza making further, and hired another 4 girls (8 now). The problem you have is that you didn't analyze your orders. If you had, you would gave seen that at any one time you only have up to 4 orders. So only 4 girls are busy. You've wasted a lot of money on staff for the rare occasions you have more than 4 orders.

You can put some of these girls on housekeeping duties, but that doesn't take much time.

Anyway, you may or may not benefit from more cores. Depends on your usage patterns. In my everyday desktop usage I wouldn't benefit from more than 4, except on the odd occasion I transcode some videos or something silly like that.

[typerlc]

Originally Posted by AdamW

transcoding video isn't an entirely safe example; many encoders for Linux are not multithreaded. ffmpeg isn't multithreaded by default yet, so any encoding done via ffmpeg doesn't benefit from multiple cores unless you do multiple videos at

I wasn't referring to the number of cores any single application may be able to use. Just the fact that you need CPU intensive apps (and several) of them to get your run queue high enough to benefit from large numbers of cores.

[AdamW]

I removed the post you quoted as it's not entirely accurate. but of course you're correct