OSNews > Thread > "0.10 scheduler comment" by pureza

Linked by Thom Holwerda on Sat 11th Aug 2007 20:46 UTC, submitted by anonymous

KernelTrap offers an informative look back in time at the November 1991 release of the 0.10 Linux kernel, continuing their historical series of articles about the early beginnings of Linux. Quite entertaining is a quote from Linus Torvalds talking about when he accidentally deleted the Minix partition that he was developing Linux from, causing him to make Linux usable for more than just reading and posting to newsgroups. The article also discusses the creation of the linux-activists mailing list, offering browsable archives of that first Linux discussion forum, full of interesting gems. And finally it describes the first Linux distribution, MCC Interim, which was created and used by the University of Manchester to teach C programming and UNIX.

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0.10 scheduler comment

by pureza on Sun 12th Aug 2007 00:48 UTC

Member since:
2005-07-06

I particularly enjoyed this comment, on kernel/sched.c:

* 'schedule()' is the scheduler function. This is GOOD CODE! There
* probably won't be any reason to change this, as it should work well
* in all circumstances (ie gives IO-bound processes good response etc).

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RE: 0.10 scheduler comment

by rx182 on Sun 12th Aug 2007 02:38 in reply to "0.10 scheduler comment"

Member since:
2005-07-08

ROFL =)

I think someone should try pluging it in recent kernel. Maybe if would fix all current issues? =)

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RE[2]: 0.10 scheduler comment

by flanque on Sun 12th Aug 2007 04:03 in reply to "RE: 0.10 scheduler comment"

Member since:
2005-12-15

Sorry, you'd have too many dependencies to resolve first. ;-)

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RE: 0.10 scheduler comment

by butters on Sun 12th Aug 2007 06:33 in reply to "0.10 scheduler comment"

Member since:
2005-07-08

This is a pretty good algorithm, all things considered. Remember, Linux won't support SMP for another four years. Traversing the task list 2-4 times isn't great, but O(N) is perfectly acceptable for dozens of tasks. Some commercial UNIX schedulers still scale linearly.

They also still use the "C = C/2 + P" function to give sleepers a bounded priority boost over hogs. Maverick sysadmins can tune the denominator these days, but the theory is identical. Yes, the algorithm is non-deterministic fuzzy math, but it's simple and it works.

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