Magenheimer, Dan (HP Labs Fort Collins)
2005-May-11 19:46 UTC
[Xen-devel] CONFIG_SMP or !CONFIG_SMP... that is the question. WAS: something about ia64 that nobody would read :-)
> From: Ian Pratt [mailto:m+Ian.Pratt@cl.cam.ac.uk]> It''s daft that we even have a CONFIG_SMP option in Xen. It spends most > of its time broken because no-one using x86 builds it, and you won''t > even be able to buy any non SMP hardware before long... > > I''d vote for expunging CONFIG_SMP.I''ve heard its not uncommon when debugging nasty problems on Linux to turn off SMP as it simplifies the world considerably. I''m not sure this same argument applies to Xen, but there''s enough kernel hackers on this list that I thought it would be interesting to open this up for discussion. Granted, turning off SMP on Xen/x86 doesn''t even compile right now, but that should be fixable. So... opinions anyone? Is keeping CONFIG_SMP (potentially) useful or not? _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Christian Limpach
2005-May-11 20:01 UTC
Re: [Xen-devel] CONFIG_SMP or !CONFIG_SMP... that is the question. WAS: something about ia64 that nobody would read :-)
On 5/11/05, Magenheimer, Dan (HP Labs Fort Collins) <dan.magenheimer@hp.com> wrote:> > From: Ian Pratt [mailto:m+Ian.Pratt@cl.cam.ac.uk] > > > It''s daft that we even have a CONFIG_SMP option in Xen. It spends most > > of its time broken because no-one using x86 builds it, and you won''t > > even be able to buy any non SMP hardware before long... > > > > I''d vote for expunging CONFIG_SMP. > > I''ve heard its not uncommon when debugging nasty problems on Linux > to turn off SMP as it simplifies the world considerably.I would either run on non-SMP hardware, use the nosmp option or if that''s gone, just nobble the code that discovers multiple CPUs -- all these are definitely preferable to compiling Xen without CONFIG_SMP since that might change the code so much that the bug might not occur anymore. christian _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Andrei Petrov
2005-May-11 21:02 UTC
Re: [Xen-devel] CONFIG_SMP or !CONFIG_SMP... that is the question. WAS: something about ia64 that nobody would read :-)
On Wed, May 11, 2005 at 12:46:08PM -0700, Magenheimer, Dan (HP Labs Fort Collins) wrote:> > Granted, turning off SMP on Xen/x86 doesn''t even compile right > now, but that should be fixable. > > So... opinions anyone? Is keeping CONFIG_SMP (potentially) useful > or not?Depends on target application area, if xen will be used in appliances or embedded systems, or laptops (think QOS, securi1y) then keeping CONFIG_SMP (!CONFIG_SMP even) would be an advantage for the project. --Andrei _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel