On Mon, Oct 20, 2014 at 2:41 PM, H. Peter Anvin <h...@zytor.com> wrote: > On 09/23/2014 10:50 AM, Andy Lutomirski wrote: >> >> Patch 8 removes the vvar that selects the getcpu mode. That vvar >> has been unnecessary for a couple of years, ever since alternative >> patching has worked in the vdso. >> > > Is there any fundamental reason to not always use LSL at this point?
No, other than aesthetics. Crappy timings on my dev box: rdtscp: 18ns (and slowdown of nearly insns because it's like lfence or mfence IIRC) lsl: 15ns just for fun, lsl of an out of bounds descriptor: 46ns lsl is also nice because it works even if CR4.TSD is set. I know I probably shouldn't say this, but sgdt is even faster (<8ns) Should I send a replacement for patch 8 or should I let you merge 1-7 and fold this into the followup series? --Andy -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/