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[patch] hp-timing for powerpc64
- From: Matthieu Castet <castet dot matthieu at free dot fr>
- To: libc-alpha at sources dot redhat dot com
- Date: Fri, 17 Jun 2005 09:49:56 +0200
- Subject: [patch] hp-timing for powerpc64
Hi,
attached macro for supporting hp-timing for powerpc64.
I could also provide one for powerpc32, but there won't be real
HP_TIMING_ACCUM.
thanks
Matthieu
/* High precision, low overhead timing functions. Generic version.
Copyright (C) 1998, 2000 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Matthieu CASTET <castet.matthieu@free.fr> 2005.
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, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#ifndef _HP_TIMING_H
#define _HP_TIMING_H 1
/* There are no generic definitions for the times. We could write something
using the `gettimeofday' system call where available but the overhead of
the system call might be too high.
In case a platform supports timers in the hardware the following macros
and types must be defined:
- 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 long long hp_timing_t;
/* Set timestamp value to zero. */
#define HP_TIMING_ZERO(Var) (Var) = (0)
/* That's quite simple. Use the `mftb' instruction.*/
#define HP_TIMING_NOW(var) __asm__ __volatile__( "mftb %0": "=r" (var) :)
/* Use two 'rdtsc' instructions in a row to find out how long it takes. */
#define HP_TIMING_DIFF_INIT() \
do { \
if (GLRO(dl_hp_timing_overhead) == 0) \
{ \
int __cnt = 5; \
GLRO(dl_hp_timing_overhead) = ~0ull; \
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))
#define HP_TIMING_ACCUM(Sum, Diff) \
do { \
__typeof (Sum) __tmp; \
__asm __volatile ("1: ldarx %0,0,%3\n" \
" add %1,%0,%4\n" \
" stdcx. %1,0,%3\n" \
" bne- 1b" \
: "=&b" (Diff), "=&r" (__tmp), "=m" (Sum) \
: "b" (&Sum), "r" (Diff), "m" (Sum) \
: "cr0", "memory"); \
} 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 (Val, __buf + sizeof (__buf), 10, 0); \
size_t __len = (Len); \
char *__dest = (Buf); \
while (__len-- > 0 && __cp < __buf + sizeof (__buf)) \
*__dest++ = *__cp++; \
memcpy (__dest, " clock cycles", MIN (__len, sizeof (" clock cycles"))); \
} while (0)
#endif /* hp-timing.h */