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authorMarcelo Tosatti <mtosatti@redhat.com>2015-04-25 04:36:14 +0300
committerPaolo Bonzini <pbonzini@redhat.com>2015-05-07 12:29:48 +0300
commita3eb97bd80134ba07864ca00747466c02118aca1 (patch)
tree07568d723daf0d61489c53bb037627d36f36878d /arch/x86/include/asm/pvclock.h
parentd90e3a35e90af7f8beceebefc90e62eae237c5ed (diff)
downloadlinux-a3eb97bd80134ba07864ca00747466c02118aca1.tar.xz
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.h1
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;