Messages in this thread | | | From | Andy Lutomirski <> | Date | Sat, 9 Jan 2016 09:57:25 -0800 | Subject | Re: [PATCH v8 3/3] x86, mce: Add __mcsafe_copy() |
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On Sat, Jan 9, 2016 at 9:48 AM, Tony Luck <tony.luck@gmail.com> wrote: > On Fri, Jan 8, 2016 at 5:49 PM, Andy Lutomirski <luto@amacapital.net> wrote: >> On Jan 8, 2016 4:19 PM, "Tony Luck" <tony.luck@intel.com> wrote: >>> >>> Make use of the EXTABLE_FAULT exception table entries. This routine >>> returns a structure to indicate the result of the copy: >> >> Perhaps this is silly, but could we make this feature depend on ERMS >> and thus make the code a lot simpler? > > ERMS?
It's the fast string extension, aka Enhanced REP MOV STOS. On CPUs with that feature (and not disabled via MSR), plain ol' rep movs is the fastest way to copy bytes. I think this includes all Intel CPUs from SNB onwards.
--Andy
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