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SubjectRe: [PATCH 7/7] uts namespaces: Implement CLONE_NEWUTS flag
Quoting Serge E. Hallyn (serue@us.ibm.com):
> Quoting Andi Kleen (ak@suse.de):
> > On Tuesday 02 May 2006 19:20, Serge E. Hallyn wrote:
> > > > With many name spaces you would have smaller task_struct, less cache
> > > > foot print, better cache use of task_struct because slab cache colouring
> > > > will still work etc.
> > >
> > > I suppose we could run some performance tests with some dummy namespace
> > > pointers? 9 void *'s directly in the task struct, and the same inside a
> > > refcounted container struct. The results might add some urgency to
> > > implementing the struct nsproxy.
> >
> > Not sure you'll notice too much difference on the beginning. I am just
>
> 9 void*'s is probably more than we'll need, though, so it's not "the
> beginning". Eric previously mentioned uts, sysvipc, net, pid, and uid,
> to which we might add proc, sysctl, and signals, though those are
> probably just implied through the others.
>
> What others do you see us needing?
>
> If the number were more likely to be 50, then in the above experiment
> use 50 instead - the point was to see the performance implications
> without implementing the namespaces first.
>
> Anyway I guess I'll go ahead and queue up some tests.

Though of course one reason those tests won't be very meaningful is that
the void*'s won't be being dereferenced, so we won't be accounting for
the performance hit of the double dereference and resulting cache
hits...

-serge
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