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The Really Fair Scheduler
derrida writes "During the many threads discussing Ingo Molnar's recently merged Completely Fair Scheduler, Roman Zippel has repeatedly questioned the complexity of the new process scheduler. In a recent posting to the Linux Kernel mailing list he offered a simpler scheduler named the 'Really Fair Scheduler' saying, 'As I already tried to explain previously CFS has a considerable algorithmic and computational complexity. This patch should now make it clearer, why I could so easily skip over Ingo's long explanation of all the tricks CFS uses to keep the computational overhead low — I simply don't need them.'"
The the fancy fair scheduler.
Still waiting for Steve Jobs' "Insanely Fair Scheduler."
If you don't know where you are going, you will wind up somewhere else.
In which no process gets any resources at all. I've also been considering a quantum scheduler, in which each CPU cycle is assigned to every process simultaneously.
Shit, I've just figured out why I'm a project manager.
Let's just go back to cooperative multitasking like Mac OS where everything was simple.
Of course, there's the companion "pork barrel scheduler" which randomly spawns useless processes in order to take time from those that deserve it.
The higher the technology, the sharper that two-edged sword.
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Completely rejecting both liberal and conservative ideals, it allocates time slices only to processes that already have them.
This is a "great" way to run things and if it ever goes to a vote, I hope lkml ops can be convinced to go the diebold route.
That just takes all the cycels and keeps them for itself?
The completely unfair scheduler, which takes all the time from processes that deserve it and gives it to processes that are blocked. Otherwise known as the liberal scheduler.
As opposed to the "REALLY completely unfair scheduler" (otherwise known as the conservative scheduler or "not nice" scheduler), which takes time from processes that need it desperately and give it to the top one tenth of one percent of processes that are swimming in priority and don't need it.
I'm waiting for a true revolution : PFS, the Porn Fair Scheduler. All processes related to porn (playback, download, etc.) receive much larger time slices than everything else.
poor guy... :(
"A Lisp programmer knows the value of everything, but the cost of nothing." - Alan Perlis
Who's the fairest scheduler made?
"To retain respect for sausages and Linux schedulers, one must not watch them in the making."
-- Otto von Bismarck (paraphrased)
I guess he should pull a Theo de Raadt, and release an OpenLinux kernel now?
Writing a fair scheduler is difficult. Why not let the user decide? I propose a popup message for each context switch: "Hello, it seems the CPU is doing a context switch. Which application to you want to allow to run this time?".
Open Source Alternatives
Or perhaps he's dreading having to say:
My name is Ingo Molnar, you kill -9ed my scheduler. Prepare to oops!
Next week: a completely new scheduler, written by Ingo, in 05:12:43.33213, called the 'Astoundingly Fair Scheduler', which doesn't look at all like this new improvement, especially - hey look ! Something shiny ! And in two weeks time, a defence written by Linus Torvalds, detailing why the AFS is so much better than the RFS, and why Ingo can be trusted so much more when it comes to maintaining stuff like that.
Religion is what happens when nature strikes and groupthink goes wrong.