gprofng/src/gethrtime.c

   1 /* Copyright (C) 2021 Free Software Foundation, Inc.
   2    Contributed by Oracle.
   3
   4    This file is part of GNU Binutils.
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3, or (at your option)
   9    any later version.
  10
  11    This program 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
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; if not, write to the Free Software
  18    Foundation, 51 Franklin Street - Fifth Floor, Boston,
  19    MA 02110-1301, USA.  */
  20
  21 #include "config.h"
  22 #include <time.h>
  23 #include <unistd.h>
  24 #include <string.h>
  25 #include <stdio.h>
  26 #include <stdlib.h>
  27 #include <sys/resource.h>
  28
  29 #include "gp-defs.h"
  30 #include "gp-time.h"
  31
  32 /* =============================================================== */
  33 /*
  34  * Below this are the get_clock_rate() and get_ncpus() for all architectures
  35  */
  36
  37 static int clock_rate = 0;
  38 static int ncpus = 0;
  39 static char msgbuf[1024];
  40
  41 int
  42 get_clock_rate (void)
  43 {
  44   /* Linux version -- read /proc/cpuinfo
  45    *    Note the parsing is different on intel-Linux and sparc-Linux
  46    */
  47   FILE *fp = fopen ("/proc/cpuinfo", "r");
  48   if (fp != NULL)
  49     {
  50
  51       char temp[1024];
  52       while (fgets (temp, sizeof (temp), fp) != NULL)
  53         {
  54 #if ARCH(SPARC)
  55           /* cpu count for SPARC linux -- read from /proc/cpuinfo */
  56           if (strncmp (temp, "ncpus active", 12) == 0)
  57             {
  58               char *val = strchr (temp, ':');
  59               ncpus = val ? atol (val + 1) : 0;
  60             }
  61 #endif /* ARCH(SPARC) */
  62
  63           if (clock_rate == 0)
  64             {
  65               /* pick the first line that gives a CPU clock rate */
  66 #if ARCH(SPARC)
  67               long long clk;
  68               if (strncmp (temp, "Cpu0ClkTck", 10) == 0)
  69                 {
  70                   char *val = strchr (temp, ':');
  71                   clk = val ? strtoll (val + 1, NULL, 16) : 0;
  72                   clock_rate = (int) (clk / 1000000);
  73                 }
  74 #else
  75               if (strncmp (temp, "cpu MHz", 7) == 0)
  76                 {
  77                   char *val = strchr (temp, ':');
  78                   clock_rate = val ? atoi (val + 1) : 0;
  79                 }
  80 #endif /* ARCH() */
  81             }
  82
  83           /* did we get a clock rate? */
  84           if (clock_rate != 0)
  85             {
  86 #if ARCH(SPARC)
  87               /* since we got a cpu count, we can break from the look */
  88               break;
  89 #endif /* ARCH(SPARC) */
  90             }
  91 #if ARCH(Intel)
  92           /* On intel-Linux, count cpus based on "cpu MHz" lines */
  93           if (strncmp (temp, "cpu MHz", 7) == 0)
  94             ncpus++;
  95 #endif /* ARCH(Intel) */
  96         }
  97       fclose (fp);
  98     }
  99
 100   if (clock_rate != 0)
 101     sprintf (msgbuf,
 102              "Clock rate = %d MHz (from reading /proc/cpuinfo) %d CPUs\n",
 103              clock_rate, ncpus);
 104
 105   /* did we get a clock rate? */
 106   if (clock_rate == 0)
 107     {
 108       clock_rate = 1000;
 109       sprintf (msgbuf, "Clock rate = %d MHz (set by default) %d CPUs\n",
 110                clock_rate, ncpus);
 111     }
 112   return clock_rate;
 113 }
 114
 115 int
 116 get_ncpus (void)
 117 {
 118   if (clock_rate == 0)
 119     get_clock_rate ();
 120   return ncpus;
 121 }
 122
 123 /* gethrvtime -- generic solution, getting user time from
 124  * clock_gettime(CLOCK_THREAD_CPUTIME_ID,..), and reformatting.
 125  * need -lrt to compile.*/
 126 hrtime_t
 127 gethrvtime ()
 128 {
 129   struct timespec tp;
 130   hrtime_t rc = 0;
 131   int r = clock_gettime (CLOCK_THREAD_CPUTIME_ID, &tp);
 132   if (r == 0)
 133     rc = ((hrtime_t) tp.tv_sec) * 1000000000 + (hrtime_t) tp.tv_nsec;
 134   return rc;
 135 }
 136
 137 /*
 138  *  CLOCK_MONOTONIC
 139  *  Clock that cannot be set and represents monotonic time since some
 140  *           unspecified starting point.
 141  */
 142 hrtime_t
 143 gethrtime (void)
 144 {
 145   struct timespec tp;
 146   hrtime_t rc = 0;
 147
 148   /*
 149    * For er_kernel on Linux, we want to match how DTrace gets its timestamps.
 150    * This is CLOCK_MONOTONIC_RAW.  It might be changing to CLOCK_MONOTONIC.
 151    * For now, we change to "RAW" and can change back if DTrace changes.
 152    *
 153    * The two can be different.  Check the clock_gettime() man page.
 154    * CLOCK_MONOTONIC_RAW is Linux-specific and introduced in 2.6.28.
 155    * It is impervious to NTP or adjtime adjustments.
 156    *
 157    * We must match the timer used in perfan/libcollector/src/gethrtime.c.
 158    *
 159    * There is no issue on Solaris, where gethrtime() is provided by the kernel
 160    * and used by DTrace.
 161    */
 162 #ifdef CLOCK_MONOTONIC_RAW
 163   int r = clock_gettime (CLOCK_MONOTONIC_RAW, &tp);
 164 #else
 165   int r = clock_gettime (CLOCK_MONOTONIC, &tp);
 166 #endif
 167   if (r == 0)
 168     rc = ((hrtime_t) tp.tv_sec) * 1000000000 + (hrtime_t) tp.tv_nsec;
 169   return rc;
 170 }