1  /* Benchmark utility functions.
       2     Copyright (C) 2015-2023 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  /* Prevent compiler to optimize away call.  */
      20  #define DO_NOT_OPTIMIZE_OUT(value)		  \
      21    ({						  \
      22      __typeof (value) __v = (value);		  \
      23      asm volatile ("" : : "r,m" (__v) : "memory"); \
      24      __v;					  \
      25    })
      26  
      27  #ifndef START_ITER
      28  # define START_ITER (100000000)
      29  #endif
      30  
      31  /* bench_start reduces the random variations due to frequency scaling by
      32     executing a small loop with many memory accesses.  START_ITER controls
      33     the number of iterations.  */
      34  
      35  void bench_start (void);