sysdeps/aarch64/hp-timing.h

   1 /* High precision, low overhead timing functions.  AArch64 version.
   2    Copyright (C) 2021-2023 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library 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 GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #ifndef _HP_TIMING_H
  20 #define _HP_TIMING_H    1
  21
  22 #include <time.h>
  23 #include <stdint.h>
  24 #include <hp-timing-common.h>
  25 #include <libc-symbols.h>
  26
  27 /* Don't use inline timer in ld.so.  */
  28 #if IS_IN(rtld)
  29 # define HP_TIMING_INLINE       (0)
  30 #else
  31 # define HP_TIMING_INLINE       (1)
  32 #endif
  33
  34 typedef uint64_t hp_timing_t;
  35
  36 #define HP_TIMING_NOW(var) \
  37   __asm__ __volatile__ ("isb; mrs %0, cntvct_el0" : "=r" (var))
  38
  39 /* Compute elapsed time in nanoseconds.  */
  40 #undef HP_TIMING_DIFF
  41 #define HP_TIMING_DIFF(Diff, Start, End)                        \
  42 ({  hp_timing_t freq;                                           \
  43     __asm__ __volatile__ ("mrs %0, cntfrq_el0" : "=r" (freq));  \
  44    (Diff) = (((End) - (Start)) * UINT64_C(1000000000 >> 6)) / (freq >> 6); \
  45 })
  46
  47 #endif  /* hp-timing.h */