Messages in this thread | | | Date | Tue, 25 Mar 2008 16:01:14 -0700 | From | "H. Peter Anvin" <> | Subject | Re: [PATCH] x86: pat cpu feature bit setting for known cpus |
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H. Peter Anvin wrote: > Ingo Molnar wrote: >> * Venki Pallipadi <venkatesh.pallipadi@intel.com> wrote: >> >>>>> OK, note previous question: what is the motivation for having >>>>> this as a whitelist (as opposed to a blacklist)? >>>> Venkatesh could tell? >>> Main reason for white-list at this point is not to be side-tracked by >>> real or potential erratas on older CPUs. Focussing on getting the >>> support for this feature on current and future CPUs. If older CPUs >>> have survived all these days without this feature, they should be >>> doing OK. >> >> well, the upside would be that since most testing of Linux kernels is >> done on _old_ hardware (people tend to risk their old hw first ;-), >> we'd get faster convergence of the codebase, even though we have the >> risk of erratas (known and unknown ones alike). Code that artificially >> limits its utility is almost always slow to stabilize. >> > > Yes, using a whitelist of this type is wrong, IMO, and smells faintly of > vendor-lockin. >
By the way, I want to clarify: I didn't mean it was *intended* as vendor-lockin, just that it's an undesirable effect of this.
-hpa
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