/* * speed.c: * Simple program to measure the speed of the various GPIO * access mechanisms. * * Copyright (c) 2012-2013 Gordon Henderson. *********************************************************************** * This file is part of wiringPi: * https://projects.drogon.net/raspberry-pi/wiringpi/ * * wiringPi is free software: you can redistribute it and/or modify * it under the terms of the GNU Lesser General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * wiringPi is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public License * along with wiringPi. If not, see . *********************************************************************** */ #include #include #include #include #define FAST_COUNT 10000000 #define SLOW_COUNT 1000000 int main (void) { int i ; uint32_t start, end, count, sum, perSec ; printf ("Raspberry Pi wiringPi speed test program\n") ; // Start the standard way if (wiringPiSetup () == -1) exit (1) ; printf ("Native wiringPi method: (%8d iterations)\n", FAST_COUNT) ; pinMode (0, OUTPUT) ; sum = 0 ; for (i = 0 ; i < 3 ; ++i) { printf (" Pass: %d: ", i) ; fflush (stdout) ; start = millis () ; for (count = 0 ; count < FAST_COUNT ; ++count) digitalWrite (0, 1) ; end = millis () ; printf (" %8dmS\n", end - start) ; sum += (end - start) ; } digitalWrite (0, 0) ; printf (" Average: %8dmS", sum / 3) ; perSec = (int)(double)FAST_COUNT / (double)((double)sum / 3.0) * 1000.0 ; printf (": %6d/sec\n", perSec) ; printf ("Native GPIO method: (%8d iterations)\n", FAST_COUNT) ; if (wiringPiSetupGpio () == -1) exit (1) ; pinMode (17, OUTPUT) ; sum = 0 ; for (i = 0 ; i < 3 ; ++i) { printf (" Pass: %d: ", i) ; fflush (stdout) ; start = millis () ; for (count = 0 ; count < 10000000 ; ++count) digitalWrite (17, 1) ; end = millis () ; printf (" %8dmS\n", end - start) ; sum += (end - start) ; } digitalWrite (17, 0) ; printf (" Average: %8dmS", sum / 3) ; perSec = (int)(double)FAST_COUNT / (double)((double)sum / 3.0) * 1000.0 ; printf (": %6d/sec\n", perSec) ; // Switch to SYS mode: if (wiringPiSetupSys () == -1) exit (1) ; printf ("/sys/class/gpio method: (%8d iterations)\n", SLOW_COUNT) ; sum = 0 ; for (i = 0 ; i < 3 ; ++i) { printf (" Pass: %d: ", i) ; fflush (stdout) ; start = millis () ; for (count = 0 ; count < SLOW_COUNT ; ++count) digitalWrite (17, 1) ; end = millis () ; printf (" %8dmS\n", end - start) ; sum += (end - start) ; } digitalWrite (17, 0) ; printf (" Average: %8dmS", sum / 3) ; perSec = (int)(double)SLOW_COUNT / (double)((double)sum / 3.0) * 1000.0 ; printf (": %6d/sec\n", perSec) ; return 0 ; }