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V2 [PATCH] x86: Use _rdtsc intrinsic for HP_TIMING_NOW
On Tue, Oct 2, 2018 at 6:45 AM H.J. Lu <hjl.tools@gmail.com> wrote:
>
> On Tue, Oct 2, 2018 at 6:15 AM Adhemerval Zanella
> <adhemerval.zanella@linaro.org> wrote:
> > I am not very found of cross abi includes like this one, wouldn't be better
> > to create a 'sysdeps/x86/hp-timing.h' and for 32-bit use _rdtsc iff
> > __i686__ is defined otherwise include generic header?
>
> I can do that.
Here is the V2 patch. OK for master?
--
H.J.
From 3adf559a0d3cc47f5cf32294d3cc6213d36718aa Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <hjl.tools@gmail.com>
Date: Mon, 1 Oct 2018 15:05:34 -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. This patch
1. Create x86 hp-timing.h to replace i686 and x86_64 hp-timing.h.
2. Move MINIMUM_ISA from init-arch.h to isa.h so that x86 hp-timing.h
can check minimum x86 ISA to decide if _rdtsc can be used.
NB: Checking if __i686__ isn't sufficient since __i686__ may not be
defined when building for i686 class processors.
* sysdeps/i386/init-arch.h: Removed.
* sysdeps/i386/i586/init-arch.h: Likewise.
* sysdeps/i386/i686/init-arch.h: Likewise.
* sysdeps/i386/i686/hp-timing.h: Likewise.
* sysdeps/x86_64/hp-timing.h: Likewise.
* sysdeps/i386/isa.h: New file.
* sysdeps/i386/i586/isa.h: Likewise.
* sysdeps/i386/i686/isa.h: Likewise.
* sysdeps/x86_64/isa.h: Likewise.
* sysdeps/x86/hp-timing.h: New file.
* sysdeps/x86/init-arch.h: Include <isa.h>.
---
sysdeps/i386/i586/{init-arch.h => isa.h} | 8 +++--
sysdeps/i386/i686/{init-arch.h => isa.h} | 8 +++--
sysdeps/i386/{init-arch.h => isa.h} | 8 +++--
sysdeps/{i386/i686 => x86}/hp-timing.h | 30 +++++++++++-------
sysdeps/x86/init-arch.h | 1 +
sysdeps/x86_64/hp-timing.h | 40 ------------------------
sysdeps/x86_64/isa.h | 23 ++++++++++++++
7 files changed, 60 insertions(+), 58 deletions(-)
rename sysdeps/i386/i586/{init-arch.h => isa.h} (89%)
rename sysdeps/i386/i686/{init-arch.h => isa.h} (89%)
rename sysdeps/i386/{init-arch.h => isa.h} (89%)
rename sysdeps/{i386/i686 => x86}/hp-timing.h (71%)
delete mode 100644 sysdeps/x86_64/hp-timing.h
create mode 100644 sysdeps/x86_64/isa.h
diff --git a/sysdeps/i386/i586/init-arch.h b/sysdeps/i386/i586/isa.h
similarity index 89%
rename from sysdeps/i386/i586/init-arch.h
rename to sysdeps/i386/i586/isa.h
index 72fb46c61e..a2b5d585d4 100644
--- a/sysdeps/i386/i586/init-arch.h
+++ b/sysdeps/i386/i586/isa.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 2015-2018 Free Software Foundation, Inc.
+/* Copyright (C) 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
@@ -15,5 +15,9 @@
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
+#ifndef _isa_h
+#define _isa_h
+
#define MINIMUM_ISA 586
-#include <sysdeps/x86/init-arch.h>
+
+#endif
diff --git a/sysdeps/i386/i686/init-arch.h b/sysdeps/i386/i686/isa.h
similarity index 89%
rename from sysdeps/i386/i686/init-arch.h
rename to sysdeps/i386/i686/isa.h
index ab99392b58..c359b13316 100644
--- a/sysdeps/i386/i686/init-arch.h
+++ b/sysdeps/i386/i686/isa.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 2015-2018 Free Software Foundation, Inc.
+/* Copyright (C) 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
@@ -15,5 +15,9 @@
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
+#ifndef _isa_h
+#define _isa_h
+
#define MINIMUM_ISA 686
-#include <sysdeps/x86/init-arch.h>
+
+#endif
diff --git a/sysdeps/i386/init-arch.h b/sysdeps/i386/isa.h
similarity index 89%
rename from sysdeps/i386/init-arch.h
rename to sysdeps/i386/isa.h
index 043089ceb9..2ac9b3d203 100644
--- a/sysdeps/i386/init-arch.h
+++ b/sysdeps/i386/isa.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 2015-2018 Free Software Foundation, Inc.
+/* Copyright (C) 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
@@ -15,5 +15,9 @@
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
+#ifndef _isa_h
+#define _isa_h
+
#define MINIMUM_ISA 486
-#include <sysdeps/x86/init-arch.h>
+
+#endif
diff --git a/sysdeps/i386/i686/hp-timing.h b/sysdeps/x86/hp-timing.h
similarity index 71%
rename from sysdeps/i386/i686/hp-timing.h
rename to sysdeps/x86/hp-timing.h
index 59af526fdb..7deb10a036 100644
--- a/sysdeps/i386/i686/hp-timing.h
+++ b/sysdeps/x86/hp-timing.h
@@ -1,7 +1,6 @@
-/* High precision, low overhead timing functions. i686 version.
- Copyright (C) 1998-2018 Free Software Foundation, Inc.
+/* High precision, low overhead timing functions. x86 version.
+ Copyright (C) 2018 Free Software Foundation, Inc.
This file is part of the GNU C Library.
- Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
@@ -17,15 +16,20 @@
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
-#ifndef _HP_TIMING_H
-#define _HP_TIMING_H 1
+#include <isa.h>
+
+#if MINIMUM_ISA == 686 || MINIMUM_ISA == 8664
+# 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)
+# define HP_TIMING_AVAIL (1)
+# define HP_SMALL_TIMING_AVAIL (1)
/* We indeed have inlined functions. */
-#define HP_TIMING_INLINE (1)
+# define HP_TIMING_INLINE (1)
/* We use 64bit values for the times. */
typedef unsigned long long int hp_timing_t;
@@ -35,8 +39,10 @@ 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))
-
-#include <hp-timing-common.h>
+# define HP_TIMING_NOW(Var) ({ (Var) = _rdtsc (); })
-#endif /* hp-timing.h */
+# include <hp-timing-common.h>
+# endif /* hp-timing.h */
+#else
+# include <sysdeps/generic/hp-timing.h>
+#endif
diff --git a/sysdeps/x86/init-arch.h b/sysdeps/x86/init-arch.h
index a81ca8a4eb..bc860fcd69 100644
--- a/sysdeps/x86/init-arch.h
+++ b/sysdeps/x86/init-arch.h
@@ -21,6 +21,7 @@
# include <ldsodefs.h>
#endif
#include <ifunc-init.h>
+#include <isa.h>
#ifndef __x86_64__
/* Due to the reordering and the other nifty extensions in i686, it is
diff --git a/sysdeps/x86_64/hp-timing.h b/sysdeps/x86_64/hp-timing.h
deleted file mode 100644
index ec543bef03..0000000000
--- a/sysdeps/x86_64/hp-timing.h
+++ /dev/null
@@ -1,40 +0,0 @@
-/* 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 */
diff --git a/sysdeps/x86_64/isa.h b/sysdeps/x86_64/isa.h
new file mode 100644
index 0000000000..9cac0cc54f
--- /dev/null
+++ b/sysdeps/x86_64/isa.h
@@ -0,0 +1,23 @@
+/* Copyright (C) 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 _isa_h
+#define _isa_h
+
+#define MINIMUM_ISA 8664
+
+#endif
--
2.17.1