I ran into a problem with Firefox on Xubuntu. Sometimes, Firefox hogs one CPU core, while all other cores are idling. Website buildup was very slow and very annoying.
I noticed that when I leave my computer alone for some time (without a reboot), something magical happens, and then Firefox again uses all CPU cores equally.
Somewhere, I read that CPU cores are attached to items in cache/buffer, and so it's actually better when a (multi-core) program temporarily uses one CPU core, instead of freeing up the other cores from their cache/buffer jobs.
Can somebody give some further explanation on how CPU loads are balanced?