Re: [RFC] cpuset: add interface to isolated cpus

[Nick Piggin <nickpiggin@yahoo.com.au>]

Paul Jackson wrote:
> Dinakar wrote:
> 
>>IMO this patch addresses just one of the requirements for partitionable
>>sched domains
> 
> 
> Correct - this particular patch was just addressing one of these.
> 
> Nick raised the reasonable concern that this patch was adding something
> to cpusets that was not especially related to cpusets.

Did you send resend the patch to remove sched-domain partitioning?
After clearing up my confusion, IMO that is needed and could probably
go into 2.6.19.

> So I will not be sending this patch to Andrew for *-mm.
> 
> There are further opportunities for improvements in some of this code,
> which my colleague Christoph Lameter may be taking an interest in.
> Ideally kernel-user API's for isolating and partitioning sched domains
> would arise from that work, though I don't know if we can wait that
> long.

The sched-domains code is all there and just ready to be used. IMO
using the cpusets API (or a slight extension thereof) would be the
best idea if we're going to use any explicit interface at all.

A cool option would be to determine the partitions according to the
disjoint set of unions of cpus_allowed masks of all tasks. I see this
getting computationally expensive though, probably O(tasks*CPUs)... I
guess that isn't too bad.

Might be better than a userspace interface.

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SUSE Labs, Novell Inc.
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