Drop unnecessary rdtsc_barrier(), as has been determined empirically, see 057e6a8c660e95c3f4e7162e00e2fee1fc90c50d for details.
Noticed by Andy Lutomirski. Improves clock_gettime() by approximately 15% on Intel i7-3520M @ 2.90GHz. Signed-off-by: Marcelo Tosatti <[email protected]> diff --git a/arch/x86/include/asm/pvclock.h b/arch/x86/include/asm/pvclock.h index 25b1cc0..a5beb23 100644 --- a/arch/x86/include/asm/pvclock.h +++ b/arch/x86/include/asm/pvclock.h @@ -86,7 +86,6 @@ unsigned __pvclock_read_cycles(const struct pvclock_vcpu_time_info *src, offset = pvclock_get_nsec_offset(src); ret = src->system_time + offset; ret_flags = src->flags; - rdtsc_barrier(); *cycles = ret; *flags = ret_flags; -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
