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| author | Marcelo Tosatti <mtosatti@redhat.com> | 2015-04-24 22:36:14 -0300 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2015-05-07 11:29:48 +0200 |
| commit | a3eb97bd80134ba07864ca00747466c02118aca1 (patch) | |
| tree | 07568d723daf0d61489c53bb037627d36f36878d /arch/x86/include/asm/pvclock.h | |
| parent | d90e3a35e90af7f8beceebefc90e62eae237c5ed (diff) | |
| download | linux-a3eb97bd80134ba07864ca00747466c02118aca1.tar.bz2 | |
x86: kvmclock: drop rdtsc_barrier()
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 <mtosatti@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/include/asm/pvclock.h')
| -rw-r--r-- | arch/x86/include/asm/pvclock.h | 1 |
1 files changed, 0 insertions, 1 deletions
diff --git a/arch/x86/include/asm/pvclock.h b/arch/x86/include/asm/pvclock.h index d6b078e9fa28..628954ceede1 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; |