Only root can do that - but only root does real-time
anyway. And I guess only rood should be able to increase
its timeslice too...
> Other hints could be "I am interactive"
Already shows up as a thread who always ends its timeslice
blocking for io. Such threads do get an priority
boost for the next timeslice.
> or "I am a batch (i.e. cpu hog)
shows up as a thread who spends its entire timeslice - these
don't get the above mentioned boost as it is assumed it gets
"enough cpu" while the interactive threads blocks.
> task" or "I am cache hot: try to keep me on this CPU".
Perhaps that might be useful.
> The scheduler tries hard to figure out the three qualities and it is
> usually right, although perhaps it can react quicker to these hints than
> it can figure things out on its own. If nothing else, this serves as a
> useful tool for determining just how accurate our O(1) scheduler is.
Well, hog/interactive is determined in one timeslice already...
The problem is that this may be abused. Someone nasty could
write a cpu hog that drops a lot of hints about being
interactive, starving real interactive programs.
Generally, it degenerates into application programmers
using _all_ the hints to get performance, so they
can beat some competitor in benchmarks. And all
other programs just get penalized.
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