On 03/27/2014 02:33 PM, Andy Lutomirski wrote: > On Thu, Mar 27, 2014 at 2:27 PM, John Stultz <john.stu...@linaro.org> wrote: >> On Thu, Mar 27, 2014 at 12:52 PM, Andy Lutomirski <l...@amacapital.net> >> wrote: >>> On 03/27/2014 04:02 AM, Clemens Ladisch wrote: >>>> Feng Tang wrote: >>>> The help text still says: >>>> | You can safely choose Y here. [...] >>>> | Choose N to continue using the legacy 8254 timer. >>>> >>>> Are these statements still true for those platforms? >>> They aren't true for modern desktop and server platforms -- the TSC is >>> used regardless of hpet availability. >> While I suspect the comment above is in relation to the non-apic >> timer. But with respect to timekeeping, our point is true assuming the >> TSC isn't mucked up by the BIOS. My 1yr old i7-3930k single socket >> system still has some wonky BIOS bug that offsets the boot core's TSC. >> And that's intel's bios, so I can only imagine other vendors have >> found other ways to cause trouble. > Is this, perhaps, an MSI X79A-GD65 (8D) (MS-7760)? If so, there's a fixed > BIOS.
Actually, an Intel DX79TO. I've harangued some folks I know, but no fixes for the BIOS have been released. >> So yea, the hpet availability for timekeeping is still important, as >> the TSC can still be problematic. > Is HPET really that much better than acpi_pm? I can read my HPET in > ~584ns (vdso) or ~649ns (syscall) and my acpi_pm in 753ns. So it's > better, but not by a whole lot. I know on older hardware it was a bigger win. I'd have to look at what my current system does. > But yes, I see no good reason to disable it, except specifically on > systems where there are known bugs. Agreed. thanks -john -- 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/
