glibc/sysdeps/generic/hp-timing.h

84 lines
3.1 KiB
C

/* 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 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
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.
*/
/* Provide dummy definitions. */
#define HP_TIMING_AVAIL (0)
#define HP_TIMING_INLINE (0)
typedef int hp_timing_t;
#define HP_TIMING_ZERO(Var)
#define HP_TIMING_NOW(var)
#define HP_TIMING_DIFF_INIT()
#define HP_TIMING_DIFF(Diff, Start, End)
#define HP_TIMING_ACCUM(Sum, Diff)
#define HP_TIMING_ACCUM_NT(Sum, Diff)
#define HP_TIMING_PRINT(Buf, Len, Val)
/* Since this implementation is not available we tell the user about it. */
#define HP_TIMING_NONAVAIL 1
#endif /* hp-timing.h */