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[PATCH] x86: Use _rdtsc intrinsic for HP_TIMING_NOW
- From: "H.J. Lu" <hjl dot tools at gmail dot com>
- To: libc-alpha at sourceware dot org
- Date: Mon, 1 Oct 2018 15:08:36 -0700
- Subject: [PATCH] x86: Use _rdtsc intrinsic for HP_TIMING_NOW
Since _rdtsc intrinsic is supported in GCC 4.9, we can use it for
HP_TIMING_NOW.
* sysdeps/i386/i686/hp-timing.h: Include <x86intrin.h>.
(HP_TIMING_NOW): Use _rdtsc.
* sysdeps/x86_64/hp-timing.h: Just include
<sysdeps/i386/i686/hp-timing.h>.
---
sysdeps/i386/i686/hp-timing.h | 4 +++-
sysdeps/x86_64/hp-timing.h | 41 +----------------------------------
2 files changed, 4 insertions(+), 41 deletions(-)
diff --git a/sysdeps/i386/i686/hp-timing.h b/sysdeps/i386/i686/hp-timing.h
index 59af526fdb..6eee8c58be 100644
--- a/sysdeps/i386/i686/hp-timing.h
+++ b/sysdeps/i386/i686/hp-timing.h
@@ -20,6 +20,8 @@
#ifndef _HP_TIMING_H
#define _HP_TIMING_H 1
+#include <x86intrin.h>
+
/* We always assume having the timestamp register. */
#define HP_TIMING_AVAIL (1)
#define HP_SMALL_TIMING_AVAIL (1)
@@ -35,7 +37,7 @@ typedef unsigned long long int hp_timing_t;
running in this moment. This could be changed by using a barrier like
'cpuid' right before the `rdtsc' instruciton. But we are not interested
in accurate clock cycles here so we don't do this. */
-#define HP_TIMING_NOW(Var) __asm__ __volatile__ ("rdtsc" : "=A" (Var))
+#define HP_TIMING_NOW(Var) ({ (Var) = _rdtsc (); })
#include <hp-timing-common.h>
diff --git a/sysdeps/x86_64/hp-timing.h b/sysdeps/x86_64/hp-timing.h
index ec543bef03..46236b9777 100644
--- a/sysdeps/x86_64/hp-timing.h
+++ b/sysdeps/x86_64/hp-timing.h
@@ -1,40 +1 @@
-/* High precision, low overhead timing functions. x86-64 version.
- Copyright (C) 2002-2018 Free Software Foundation, Inc.
- This file is part of the GNU C Library.
-
- The GNU C Library is free software; you can redistribute it and/or
- modify it under the terms of the GNU Lesser General Public
- License as published by the Free Software Foundation; either
- version 2.1 of the License, or (at your option) any later version.
-
- The GNU C Library is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- Lesser General Public License for more details.
-
- You should have received a copy of the GNU Lesser General Public
- License along with the GNU C Library; if not, see
- <http://www.gnu.org/licenses/>. */
-
-#ifndef _HP_TIMING_H
-#define _HP_TIMING_H 1
-
-/* We always assume having the timestamp register. */
-#define HP_TIMING_AVAIL (1)
-#define HP_SMALL_TIMING_AVAIL (1)
-
-/* We indeed have inlined functions. */
-#define HP_TIMING_INLINE (1)
-
-/* We use 64bit values for the times. */
-typedef unsigned long long int hp_timing_t;
-
-/* The "=A" constraint used in 32-bit mode does not work in 64-bit mode. */
-#define HP_TIMING_NOW(Var) \
- ({ unsigned int _hi, _lo; \
- asm volatile ("rdtsc" : "=a" (_lo), "=d" (_hi)); \
- (Var) = ((unsigned long long int) _hi << 32) | _lo; })
-
-#include <hp-timing-common.h>
-
-#endif /* hp-timing.h */
+#include <sysdeps/i386/i686/hp-timing.h>
--
2.17.1