linux/cycles.h

   1 /*
   2   Copyright (C) 2001 Paul Davis
   3   Code derived from various headers from the Linux kernel
   4
   5   This program is free software; you can redistribute it and/or modify
   6   it under the terms of the GNU General Public License as published by
   7   the Free Software Foundation; either version 2 of the License, or
   8   (at your option) any later version.
   9
  10   This program is distributed in the hope that it will be useful,
  11   but WITHOUT ANY WARRANTY; without even the implied warranty of
  12   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13   GNU General Public License for more details.
  14
  15   You should have received a copy of the GNU General Public License
  16   along with this program; if not, write to the Free Software
  17   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  18
  19   $Id: cycles.h,v 1.4.2.1 2006/06/20 14:44:00 letz Exp $
  20 */
  21
  22 #ifndef __jack_cycles_h__
  23 #define __jack_cycles_h__
  24
  25 /*
  26  * Standard way to access the cycle counter on i586+ CPUs.
  27  * Currently only used on SMP.
  28  *
  29  * If you really have a SMP machine with i486 chips or older,
  30  * compile for that, and this will just always return zero.
  31  * That's ok, it just means that the nicer scheduling heuristics
  32  * won't work for you.
  33  *
  34  * We only use the low 32 bits, and we'd simply better make sure
  35  * that we reschedule before that wraps. Scheduling at least every
  36  * four billion cycles just basically sounds like a good idea,
  37  * regardless of how fast the machine is.
  38  */
  39
  40 #ifdef __x86_64__
  41
  42 typedef unsigned long cycles_t;
  43 extern cycles_t cacheflush_time;
  44
  45 static inline unsigned long get_cycles(void)
  46 {
  47     unsigned int hi, lo;
  48     __asm__ __volatile__ ("rdtsc" : "=a"(lo), "=d"(hi));
  49     return (((unsigned long)hi)<<32) | ((unsigned long)lo);
  50 }
  51
  52 #endif /* __x86_64__ */
  53
  54 #ifdef __sparc_v9__
  55 /* rd is V9 only */
  56 static inline unsigned long long get_cycles(void)
  57 {
  58         unsigned long long res;
  59         __asm__ __volatile__("rd %%tick, %0" : "=r"(res));
  60         return res;
  61 }
  62 #endif /* __sparc_v9__ */
  63
  64 #ifdef __PPC__
  65
  66 /* PowerPC */
  67
  68 #define CPU_FTR_601                     0x00000100
  69
  70 typedef unsigned long cycles_t;
  71
  72 /* For the "cycle" counter we use the timebase lower half. */
  73
  74 extern cycles_t cacheflush_time;
  75
  76 static inline cycles_t get_cycles(void)
  77 {
  78     cycles_t ret = 0;
  79
  80     __asm__ __volatile__(
  81         "98:    mftb %0\n"
  82         "99:\n"
  83         ".section __ftr_fixup,\"a\"\n"
  84         "       .long %1\n"
  85         "       .long 0\n"
  86         "       .long 98b\n"
  87         "       .long 99b\n"
  88         ".previous"
  89     : "=r" (ret) : "i" (CPU_FTR_601));
  90     return ret;
  91 }
  92
  93 #endif /* __PPC__ */
  94
  95 #ifdef __i386__
  96
  97 typedef unsigned long long cycles_t;
  98
  99 extern cycles_t cacheflush_time;
 100
 101 #define rdtscll(val) \
 102      __asm__ __volatile__("rdtsc" : "=A" (val))
 103
 104 static inline cycles_t get_cycles (void)
 105 {
 106     unsigned long long ret;
 107
 108     rdtscll(ret);
 109     return ret;
 110 }
 111
 112 #endif /* __i386__ */
 113
 114 /* everything else but x86, amd64, sparcv9 or ppc */
 115 #if !defined (__PPC__) && !defined (__x86_64__) && !defined (__i386__) && !defined (__sparc_v9__)
 116
 117 #warning No suitable get_cycles() implementation. Returning 0 instead
 118
 119 typedef unsigned long long cycles_t;
 120
 121 static inline cycles_t get_cycles(void)
 122 {
 123     return 0;
 124 }
 125
 126 #endif /* everything else but x86, amd64, sparcv9 or ppc */
 127
 128
 129 #endif /* __jack_cycles_h__ */