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428dd03f5a
Without HP_TIMING_ACCUM, dl_hp_timing_overhead is write-only. If we remove it, there's no point in HP_TIMING_DIFF_INIT either.
98 lines
3.6 KiB
C
98 lines
3.6 KiB
C
/* High precision, low overhead timing functions. Alpha version.
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Copyright (C) 2001-2014 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Richard Henderson <rth@redhat.com>, 2001.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library. If not, see
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<http://www.gnu.org/licenses/>. */
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#ifndef _HP_TIMING_H
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#define _HP_TIMING_H 1
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#include <string.h>
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#include <sys/param.h>
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#include <_itoa.h>
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/* The macros defined here use the timestamp counter in IA-64. They
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provide a very accurate way to measure the time with very little
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overhead. The time values themself have no real meaning, only
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differences are interesting.
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The list of macros we need includes the following:
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- HP_TIMING_AVAIL: test for availability.
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- HP_TIMING_INLINE: this macro is non-zero if the functionality is not
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implemented using function calls but instead uses some inlined code
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which might simply consist of a few assembler instructions. We have to
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know this since we might want to use the macros here in places where we
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cannot make function calls.
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- hp_timing_t: This is the type for variables used to store the time
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values.
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- HP_TIMING_NOW: place timestamp for current time in variable given as
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parameter.
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- HP_TIMING_DIFF: compute difference between two times and store it
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in a third. Source and destination might overlap.
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- HP_TIMING_ACCUM_NT: add time difference to another variable, without
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being thread-safe.
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- HP_TIMING_PRINT: write decimal representation of the timing value into
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the given string. This operation need not be inline even though
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HP_TIMING_INLINE is specified.
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*/
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/* We always have the timestamp register, but it's got only a 4 second
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range. Use it for ld.so profiling only. */
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#define HP_TIMING_AVAIL (0)
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#define HP_SMALL_TIMING_AVAIL (1)
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/* We indeed have inlined functions. */
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#define HP_TIMING_INLINE (1)
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/* We use 32 bit values for the times. */
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typedef unsigned int hp_timing_t;
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/* The "rpcc" instruction returns a 32-bit counting half and a 32-bit
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"virtual cycle counter displacement". Subtracting the two gives us
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a virtual cycle count. */
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#define HP_TIMING_NOW(VAR) \
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do { \
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unsigned long int x_; \
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asm volatile ("rpcc %0" : "=r"(x_)); \
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(VAR) = (int) (x_) - (int) (x_ >> 32); \
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} while (0)
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/* It's simple arithmetic for us. */
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#define HP_TIMING_DIFF(Diff, Start, End) (Diff) = ((End) - (Start))
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#define HP_TIMING_ACCUM_NT(Sum, Diff) (Sum) += (Diff)
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/* Print the time value. */
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#define HP_TIMING_PRINT(Buf, Len, Val) \
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do { \
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char __buf[20]; \
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char *__cp = _itoa_word (Val, __buf + sizeof (__buf), 10, 0); \
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int __len = (Len); \
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char *__dest = (Buf); \
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while (__len-- > 0 && __cp < __buf + sizeof (__buf)) \
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*__dest++ = *__cp++; \
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memcpy (__dest, " clock cycles", MIN (__len, sizeof (" clock cycles"))); \
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} while (0)
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#endif /* hp-timing.h */
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