| 1 | /* Return frequency of ticks reported by profil. Generic version. */ |
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| 2 | /*- |
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| 3 | * Copyright (c) 1983, 1992, 1993 |
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| 4 | * The Regents of the University of California. All rights reserved. |
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| 5 | * |
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| 6 | * Redistribution and use in source and binary forms, with or without |
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| 7 | * modification, are permitted provided that the following conditions |
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| 8 | * are met: |
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| 9 | * 1. Redistributions of source code must retain the above copyright |
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| 10 | * notice, this list of conditions and the following disclaimer. |
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| 11 | * 2. Redistributions in binary form must reproduce the above copyright |
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| 12 | * notice, this list of conditions and the following disclaimer in the |
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| 13 | * documentation and/or other materials provided with the distribution. |
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| 14 | * 4. Neither the name of the University nor the names of its contributors |
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| 15 | * may be used to endorse or promote products derived from this software |
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| 16 | * without specific prior written permission. |
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| 17 | * |
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| 18 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
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| 19 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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| 20 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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| 21 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
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| 22 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
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| 23 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
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| 24 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
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| 25 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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| 26 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
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| 27 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
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| 28 | * SUCH DAMAGE. |
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| 29 | */ |
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| 30 | |
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| 31 | |
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| 32 | #include <sys/types.h> |
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| 33 | #include <sys/time.h> |
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| 34 | #include <libc-internal.h> |
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| 35 | |
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| 36 | int |
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| 37 | __profile_frequency (void) |
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| 38 | { |
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| 39 | /* |
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| 40 | * Discover the tick frequency of the machine if something goes wrong, |
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| 41 | * we return 0, an impossible hertz. |
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| 42 | */ |
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| 43 | struct itimerval tim; |
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| 44 | |
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| 45 | tim.it_interval.tv_sec = 0; |
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| 46 | tim.it_interval.tv_usec = 1; |
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| 47 | tim.it_value.tv_sec = 0; |
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| 48 | tim.it_value.tv_usec = 0; |
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| 49 | setitimer(ITIMER_REAL, &tim, 0); |
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| 50 | setitimer(ITIMER_REAL, 0, &tim); |
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| 51 | if (tim.it_interval.tv_usec < 2) |
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| 52 | return 0; |
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| 53 | return (1000000 / tim.it_interval.tv_usec); |
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| 54 | } |
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