Re: [Xen-ia64-devel] RE: PATCH: dom_rid_bits command line parameter

[Tristan Gingold <Tristan.Gingold@xxxxxxxx>]

Le Vendredi 14 Avril 2006 16:39, Magenheimer, Dan (HP Labs Fort Collins) a 
écrit :
> I suggest changing the comment from "host rid space is shared
> among the domains" to "host rid space is partitioned among
> the domains". 
Ok.

> Also it might be wise to complain/panic if
> dom_rid_bits is set > 22.  If 23, only dom0 can run (no domUs).
This may be still useful.
Also note:
        printf ("Maximum of simultaneous domains: %d\n",
                (1 << (implemented_rid_bits - domain_rid_bits_default)) - 1);

> Perhaps also if dom_rid_bits is set at all, a descriptive
> message should be printed stating "dom_rid_bits is set to xx;
> each domain has yy rids".
Ok.

> Should dom_rid_bits < 18 be allowed?  Architecturally the
> answer is no, but if all guests support it, a system adminstrator
> might choose to make the tradeoff (worse performance in each
> domain for more concurrent domains).
It is useless to allow it unless you redefine IA64_MIN_IMPL_RID_BITS.  This is 
due to:

if (ridbits < IA64_MIN_IMPL_RID_BITS)
                ridbits = IA64_MIN_IMPL_RID_BITS;

Thank you for your comments,
Tristan.


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