Messages in this thread | | | Date | Tue, 6 Jan 2009 16:30:55 +0100 | From | Nick Piggin <> | Subject | Re: [patch] x86: make UV support optional |
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On Tue, Jan 06, 2009 at 07:05:42AM -0800, Mike Travis wrote: > Nick Piggin wrote: > > On Tue, Jan 06, 2009 at 08:33:30AM -0600, Jack Steiner wrote: > >> On Tue, Jan 06, 2009 at 07:03:48AM +0100, Nick Piggin wrote: > >>> UV is fairly rare.... and much of the support is already there to cope with > >>> 32-bit builds. So this makes sense I think. > > What, you haven't heard of "UV on a chip"? It will be in every > smart phone soon... ;-)
NUMAlink over microwave? Cool!
> >> Looks ok to me. One suggestion though. There is a MAXSMP config > >> option. I would suggest enabling UV if MAXSMP is enabled. This > >> will help ensure that UV is tested more frequently & may minimize > >> regressions. > > > > Yeah.... I don't know. OTOH it would be more logical to enable > > MAXSMP iff UV is enabled (or change the MAXSMP limits for when > > UV is enabled). Or you could select Intel CPUs if UV is enabled, > > or disable GRU if UV is not set etc etc. > > > > I didn't want to get too fancy with config options because arbitrary > > linkages seem to just cause headaches. I figure if someone wants > > to enable it, they can do so. > > > > Hi Nick, > > The problem arises that if the option becomes too obscure (and never > enabled), then it won't get tested. We (as many companies do) rely on > distros to certify applications and security features using a standard > kernel, and if an option (such as X86_UV) causes any problems whatsoever, > they'll drop it and we no longer have that application certification.
I wouldn't be so pessimistic ;) The people involved should have a shared interest in the feature so then they will fix it.
It might be nice for one person to enable their code on everyone's builds, but it's kind of a selfish viewpoint (imagine if everyone did it).
> Currently, Ingo's test setup sets MAXSMP quite a bit and he's found > many problems with large NR_CPUS counts that we never would have found > ourselves. Please don't make that process any harder.
Ingo's setup does randconfigs I think? Then it should pick up this option.
> In fact, 13k is peanuts.
Ahh, you SGIers ;) Everything adds up, and 13k is a gold mine for some people, especially considering how unintrusive the patch is.
> Why don't you set something like "very minimal > support" and drop all obsolete features, anything older than a couple of > years, anything not available from Dell ;-) Perhaps call it "Desktop > System"?
Well, because I don't perceive any benefit from doing that :)
In the end I don't want to make a big deal of it so long as it is configurable. I'll resubmit the patch, and let others play with Kconfig...
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