1 /* Benchmark utility functions. 2 Copyright (C) 2015-2022 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); 36