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authorMike Frysinger <vapier@gentoo.org>2014-02-15 22:07:25 -0500
committerMike Frysinger <vapier@gentoo.org>2014-02-16 01:12:38 -0500
commitc70a4b1db0cf5e813ae24b0fa96a352399eb6edf (patch)
tree5a36b0f0955682ae5232907d04fdf68589990783 /sysdeps/ia64/hp-timing.h
parent591aeaf7a99bc9aa9179f013114d92496952dced (diff)
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ia64: relocate out of ports/ subdir
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+/* High precision, low overhead timing functions.  IA-64 version.
+   Copyright (C) 2001-2014 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Ulrich Drepper <drepper@cygnus.com>, 2001.
+
+   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
+
+#include <string.h>
+#include <sys/param.h>
+#include <_itoa.h>
+#include <ia64intrin.h>
+
+/* The macros defined here use the timestamp counter in IA-64.  They
+   provide a very accurate way to measure the time with very little
+   overhead.  The time values themself have no real meaning, only
+   differences are interesting.
+
+   The list of macros we need includes the following:
+
+   - HP_TIMING_AVAIL: test for availability.
+
+   - HP_TIMING_INLINE: this macro is non-zero if the functionality is not
+     implemented using function calls but instead uses some inlined code
+     which might simply consist of a few assembler instructions.  We have to
+     know this since we might want to use the macros here in places where we
+     cannot make function calls.
+
+   - hp_timing_t: This is the type for variables used to store the time
+     values.
+
+   - HP_TIMING_ZERO: clear `hp_timing_t' object.
+
+   - HP_TIMING_NOW: place timestamp for current time in variable given as
+     parameter.
+
+   - HP_TIMING_DIFF_INIT: do whatever is necessary to be able to use the
+     HP_TIMING_DIFF macro.
+
+   - HP_TIMING_DIFF: compute difference between two times and store it
+     in a third.  Source and destination might overlap.
+
+   - HP_TIMING_ACCUM: add time difference to another variable.  This might
+     be a bit more complicated to implement for some platforms as the
+     operation should be thread-safe and 64bit arithmetic on 32bit platforms
+     is not.
+
+   - HP_TIMING_ACCUM_NT: this is the variant for situations where we know
+     there are no threads involved.
+
+   - HP_TIMING_PRINT: write decimal representation of the timing value into
+     the given string.  This operation need not be inline even though
+     HP_TIMING_INLINE is specified.
+
+*/
+
+/* We always assume having the timestamp register.  */
+#define HP_TIMING_AVAIL		(1)
+
+/* We indeed have inlined functions.  */
+#define HP_TIMING_INLINE	(1)
+
+/* We use 64bit values for the times.  */
+typedef unsigned long int hp_timing_t;
+
+/* Set timestamp value to zero.  */
+#define HP_TIMING_ZERO(Var)	(Var) = (0)
+
+
+/* The Itanium/Merced has a bug where the ar.itc register value read
+   is not correct in some situations.  The solution is to read again.
+   For now we always do this until we know how to recognize a fixed
+   processor implementation.  */
+#define REPEAT_READ(val) __builtin_expect ((long int) val == -1, 0)
+
+/* That's quite simple.  Use the `ar.itc' instruction.  */
+#define HP_TIMING_NOW(Var) \
+  ({ unsigned long int __itc;						      \
+     do									      \
+       asm volatile ("mov %0=ar.itc" : "=r" (__itc) : : "memory");	      \
+     while (REPEAT_READ (__itc));					      \
+     Var = __itc; })
+
+/* Use two 'ar.itc' instructions in a row to find out how long it takes.  */
+#define HP_TIMING_DIFF_INIT() \
+  do {									      \
+    int __cnt = 5;							      \
+    GLRO(dl_hp_timing_overhead) = ~0ul;					      \
+    do									      \
+      {									      \
+	hp_timing_t __t1, __t2;						      \
+	HP_TIMING_NOW (__t1);						      \
+	HP_TIMING_NOW (__t2);						      \
+	if (__t2 - __t1 < GLRO(dl_hp_timing_overhead))			      \
+	  GLRO(dl_hp_timing_overhead) = __t2 - __t1;			      \
+      }									      \
+    while (--__cnt > 0);						      \
+  } while (0)
+
+/* It's simple arithmetic for us.  */
+#define HP_TIMING_DIFF(Diff, Start, End)	(Diff) = ((End) - (Start))
+
+/* We have to jump through hoops to get this correctly implemented.  */
+#define HP_TIMING_ACCUM(Sum, Diff) \
+  do {									      \
+    hp_timing_t __oldval;						      \
+    hp_timing_t __diff = (Diff) - GLRO(dl_hp_timing_overhead);		      \
+    hp_timing_t __newval;						      \
+    do									      \
+      {									      \
+	__oldval = (Sum);						      \
+	__newval = __oldval + __diff;					      \
+      }									      \
+    while (! __sync_bool_compare_and_swap (&Sum, __oldvar, __newval));	      \
+  } while (0)
+
+/* No threads, no extra work.  */
+#define HP_TIMING_ACCUM_NT(Sum, Diff)	(Sum) += (Diff)
+
+/* Print the time value.  */
+#define HP_TIMING_PRINT(Buf, Len, Val) \
+  do {									      \
+    char __buf[20];							      \
+    char *__cp = _itoa_word (Val, __buf + sizeof (__buf), 10, 0);	      \
+    int __len = (Len);							      \
+    char *__dest = (Buf);						      \
+    while (__len-- > 0 && __cp < __buf + sizeof (__buf))		      \
+      *__dest++ = *__cp++;						      \
+    memcpy (__dest, " clock cycles", MIN (__len,			      \
+					  (int) sizeof (" clock cycles")));   \
+  } while (0)
+
+#endif	/* hp-timing.h */