include/ust/clock.h

   1 /* Copyright (C) 2010  Pierre-Marc Fournier
   2  *
   3  * This library is free software; you can redistribute it and/or
   4  * modify it under the terms of the GNU Lesser General Public
   5  * License as published by the Free Software Foundation; either
   6  * version 2.1 of the License, or (at your option) any later version.
   7  *
   8  * This library is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * Lesser General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU Lesser General Public
  14  * License along with this library; if not, write to the Free Software
  15  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
  16  */
  17
  18 #ifndef UST_CLOCK_H
  19 #define UST_CLOCK_H
  20
  21 #include <sys/time.h>
  22 #include <ust/kcompat/kcompat.h>
  23
  24 /* TRACE CLOCK */
  25
  26 /* There are two types of clocks that can be used.
  27    - TSC based clock
  28    - gettimeofday() clock
  29
  30    Microbenchmarks on Linux 2.6.30 on Core2 Duo 3GHz (functions are inlined):
  31      Calls (100000000) to tsc(): 4004035641 cycles or 40 cycles/call
  32      Calls (100000000) to gettimeofday(): 9723158352 cycles or 97 cycles/call
  33
  34    For merging traces with the kernel, a time source compatible with that of
  35    the kernel is necessary.
  36
  37 */
  38
  39 #define TRACE_CLOCK_GENERIC
  40 #ifdef TRACE_CLOCK_GENERIC
  41
  42 static __inline__ u64 trace_clock_read64(void)
  43 {
  44         struct timeval tv;
  45         u64 retval;
  46
  47         gettimeofday(&tv, NULL);
  48         retval = tv.tv_sec;
  49         retval *= 1000000;
  50         retval += tv.tv_usec;
  51
  52         return retval;
  53 }
  54
  55 #else
  56
  57 #if __i386 || __x86_64
  58
  59 /* WARNING: Make sure to set frequency and scaling functions that will not
  60  * result in lttv timestamps (sec.nsec) with seconds greater than 2**32-1.
  61  */
  62 static __inline__ u64 trace_clock_read64(void)
  63 {
  64         uint32_t low;
  65         uint32_t high;
  66         uint64_t retval;
  67         __asm__ volatile ("rdtsc\n" : "=a" (low), "=d" (high));
  68
  69         retval = high;
  70         retval <<= 32;
  71         return retval | low;
  72 }
  73
  74 #endif /* __i386 || __x86_64 */
  75
  76 #ifdef __PPC__
  77
  78 static __inline__ u64 trace_clock_read64(void)
  79 {
  80         unsigned long tb_l;
  81         unsigned long tb_h;
  82         unsigned long tb_h2;
  83         u64 tb;
  84
  85         __asm__ (
  86                 "1:\n\t"
  87                 "mftbu %[rhigh]\n\t"
  88                 "mftb %[rlow]\n\t"
  89                 "mftbu %[rhigh2]\n\t"
  90                 "cmpw %[rhigh],%[rhigh2]\n\t"
  91                 "bne 1b\n\t"
  92         : [rhigh] "=r" (tb_h), [rhigh2] "=r" (tb_h2), [rlow] "=r" (tb_l));
  93
  94         tb = tb_h;
  95         tb <<= 32;
  96         tb |= tb_l;
  97
  98         return tb;
  99 }
 100
 101 #endif /* __PPC__ */
 102
 103 #endif /* ! UST_TRACE_CLOCK_GENERIC */
 104
 105 static __inline__ u64 trace_clock_frequency(void)
 106 {
 107         return 1000000LL;
 108 }
 109
 110 static __inline__ u32 trace_clock_freq_scale(void)
 111 {
 112         return 1;
 113 }
 114
 115 #endif /* UST_CLOCK_H */