Messages in this thread | | | Date | Fri, 26 Jan 2007 11:31:42 +0530 | From | Srivatsa Vaddagiri <> | Subject | [RFC] Fair-user scheduler |
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Current Linux CPU scheduler doesnt recognize process aggregates while allocating bandwidth. As a result of this, an user could simply spawn large number of processes and get more bandwidth than others.
Here's a patch that provides fair allocation for all users in a system.
Some benchmark numbers with and without the patch applied follows:
user "vatsa" user "guest" (make -s -j4 bzImage) (make -s -j20 bzImage)
2.6.20-rc5 472.07s (real) 257.48s (real) 2.6.20-rc5+fairsched 766.74s (real) 766.73s (real)
(Numbers taken on a 2way Intel x86_64 box)
Eventually something like this can be extended to do weighted fair share scheduling for:
- KVM - containers - resource management
Salient features of the patch:
- Based on Ingo's RTLIMIT_RT_CPU patch [1]. Primary difference between RTLIMIT_RT_CPU patch and this one is that this patch handles starvation of lower priority tasks in a group and also accounting is token based (rather than decaying avg).
- Retains existing one-runqueue-per-cpu design
- breaks O(1) (ouch!) Best way to avoid this is to split runqueue to be per-user and per-cpu, which I have not implemented to keep the patch simple.
- Fairsched aware SMP load balance NOT addressed (yet)
Comments/flames wellcome!
References:
1. http://kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.11-rc2/2.6.11-rc2-mm2/broken-out/rlimit_rt_cpu.patch
-- Regards, vatsa - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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