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[glibc.git] / sysdeps / generic / hp-timing.h
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1 /* High precision, low overhead timing functions. Generic version.
2 Copyright (C) 1998, 2000 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4 Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998.
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
11 The GNU C Library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, write to the Free
18 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
19 02111-1307 USA. */
21 #ifndef _HP_TIMING_H
22 #define _HP_TIMING_H 1
25 /* There are no generic definitions for the times. We could write something
26 using the `gettimeofday' system call where available but the overhead of
27 the system call might be too high.
29 In case a platform supports timers in the hardware the following macros
30 and types must be defined:
32 - HP_TIMING_AVAIL: test for availability.
34 - HP_TIMING_INLINE: this macro is non-zero if the functionality is not
35 implemented using function calls but instead uses some inlined code
36 which might simply consist of a few assembler instructions. We have to
37 know this since we might want to use the macros here in places where we
38 cannot make function calls.
40 - hp_timing_t: This is the type for variables used to store the time
41 values.
43 - HP_TIMING_ZERO: clear `hp_timing_t' object.
45 - HP_TIMING_NOW: place timestamp for current time in variable given as
46 parameter.
48 - HP_TIMING_DIFF_INIT: do whatever is necessary to be able to use the
49 HP_TIMING_DIFF macro.
51 - HP_TIMING_DIFF: compute difference between two times and store it
52 in a third. Source and destination might overlap.
54 - HP_TIMING_ACCUM: add time difference to another variable. This might
55 be a bit more complicated to implement for some platforms as the
56 operation should be thread-safe and 64bit arithmetic on 32bit platforms
57 is not.
59 - HP_TIMING_ACCUM_NT: this is the variant for situations where we know
60 there are no threads involved.
62 - HP_TIMING_PRINT: write decimal representation of the timing value into
63 the given string. This operation need not be inline even though
64 HP_TIMING_INLINE is specified.
68 /* Provide dummy definitions. */
69 #define HP_TIMING_AVAIL (0)
70 #define HP_TIMING_INLINE (0)
71 typedef int hp_timing_t;
72 #define HP_TIMING_ZERO(Var)
73 #define HP_TIMING_NOW(var)
74 #define HP_TIMING_DIFF_INIT()
75 #define HP_TIMING_DIFF(Diff, Start, End)
76 #define HP_TIMING_ACCUM(Sum, Diff)
77 #define HP_TIMING_ACCUM_NT(Sum, Diff)
78 #define HP_TIMING_PRINT(Buf, Len, Val)
80 /* Since this implementation is not available we tell the user about it. */
81 #define HP_TIMING_NONAVAIL 1
83 #endif /* hp-timing.h */