Messages in this thread | | | Date | Mon, 20 Apr 2015 19:45:44 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH 1/1] x86: replace cpu_up hard-coded mdelay with variable |
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* Brown, Len <len.brown@intel.com> wrote:
> > What's the cutoff for 'modern hardware' - which CPUs stopped requiring > > the delay? > > This is the topic of ongoing research, and I'm not ready to send > the patch setting a new default until I've heard back from a few more HW people. > > Every system I've tested appears to work with delay 0. > Were I to guess, I'd venture that every > system that runs an X86_64 kernel might count as "modern" -- even > the 2005 AMD Turion laptop I've got in the bone pile.
Could we use the apic version as a cutoff perhaps?
It would be nice to 'automatically' include modern 32-bit x86 systems as well.
Any failure here would be relatively easy to bisect to, so we might as well guess a bit and refine the quirk condition if needed?
Thanks,
Ingo
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