108 lines
3.0 KiB
C
108 lines
3.0 KiB
C
/* Low-level statistical profiling support function. Mostly POSIX.1 version.
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Copyright (C) 1996 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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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 Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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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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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If
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not, write to the Free Software Foundation, Inc., 675 Mass Ave,
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Cambridge, MA 02139, USA. */
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#include <sys/types.h>
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#include <unistd.h>
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#include <errno.h>
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#include <signal.h>
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#include <sys/time.h>
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#ifndef SIGPROF
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#include_next <profil.c>
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#else
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static u_short *samples;
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static size_t nsamples;
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static size_t pc_offset;
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static u_int pc_scale;
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static inline void
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profil_count (void *pc)
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{
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size_t i = (pc - pc_offset - (void *) 0) / 2;
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if (sizeof (unsigned long long int) > sizeof (size_t))
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i = (unsigned long long int) i * pc_scale / 65536;
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else
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i = i / 65536 * pc_scale + i % 65536 * pc_scale / 65536;
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if (i < nsamples)
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++samples[i];
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}
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/* Get the machine-dependent definition of `profil_counter', the signal
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handler for SIGPROF. It calls `profil_count' (above) with the PC of the
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interrupted code. */
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#include "profil-counter.h"
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/* Enable statistical profiling, writing samples of the PC into at most
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SIZE bytes of SAMPLE_BUFFER; every processor clock tick while profiling
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is enabled, the system examines the user PC and increments
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SAMPLE_BUFFER[((PC - OFFSET) / 2) * SCALE / 65536]. If SCALE is zero,
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disable profiling. Returns zero on success, -1 on error. */
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int
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profil (u_short *sample_buffer, size_t size, size_t offset, u_int scale)
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{
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static struct sigaction act, oact;
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static struct itimerval timer, otimer;
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if (sample_buffer == NULL)
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{
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/* Disable profiling. */
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if (samples == NULL)
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/* Wasn't turned on. */
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return 0;
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if (setitimer (ITIMER_PROF, &otimer, NULL) < 0)
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return -1;
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samples = NULL;
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return sigaction (SIGPROF, &oact, NULL);
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}
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if (samples)
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{
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/* Was already turned on. Restore old timer and signal handler
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first. */
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if (setitimer (ITIMER_PROF, &otimer, NULL) < 0
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|| sigaction (SIGPROF, &oact, NULL) < 0)
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return -1;
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}
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samples = sample_buffer;
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nsamples = size / sizeof *samples;
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pc_offset = offset;
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pc_scale = scale;
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act.sa_handler = (sighandler_t) &profil_counter;
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act.sa_flags = SA_RESTART;
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sigfillset (&act.sa_mask);
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if (sigaction (SIGPROF, &act, &oact) < 0)
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return -1;
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timer.it_value.tv_sec = 0;
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timer.it_value.tv_usec = 1;
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timer.it_interval = timer.it_value;
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return setitimer (ITIMER_PROF, &timer, &otimer);
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}
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#endif
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