Re: [RFC] CPU controllers?

From: Nick Piggin
Date: Sun Jun 18 2006 - 03:48:21 EST


Mike Galbraith wrote:
On Sat, 2006-06-17 at 23:42 -0700, Andrew Morton wrote:

On Sun, 18 Jun 2006 16:11:18 +1000
Nick Piggin <nickpiggin@xxxxxxxxxxxx> wrote:


Again, I don't care about the solutions at this stage. I want to know
what the problem is. Please?

Isolation. To prevent one group of processes from damaging the performance
of other groups, by providing manageability of the resource consumption of
each group. There are plenty of applications of this, not just
server-consolidation-via-server-virtualisation.


Scheduling contexts do sound useful. They're easily defeated though, as
evolution mail demonstrates to me every time it's GUI hangs and I see
that a nice 19 find is running, eating very little CPU, but effectively
DoSing evolution nonetheless (journal). I wonder how often people who
tried to distribute CPU would likewise be stymied by other resources.

Not entirely infrequently. Which is why it really doesn't seem like
it could be useful from a security point of view without a *huge*
amount of work and complexity... and even from a guaranteed-service
point of view, it still seems (to me) like a pretty big and complex
problem.

As a check box for marketing it sounds pretty cool though, I admit ;)

--
SUSE Labs, Novell Inc.
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