| /****************************************************************************** |
| * |
| * Copyright © International Business Machines Corp., 2006, 2008 |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; either version 2 of the License, or |
| * (at your option) any later version. |
| * |
| * This program 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 General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program; if not, write to the Free Software |
| * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| * |
| * NAME |
| * prio-preempt.c |
| * |
| * DESCRIPTION |
| * Test whether priority pre-emption works fine. |
| * |
| * The main thread: |
| * - Creates a minimum of (N-1) busy threads at priority starting at |
| * SCHED_FIFO + 80 |
| * - Creates 26 FIFO (T1, T2,...,T26) threads with priorities 10, 11,...,36. |
| * - Each of these worker threads executes the following piece of code: |
| * pthread_mutex_lock(Mi); |
| * pthread_cond_wait(CVi); |
| * pthread_mutex_unlock(Mi); |
| * |
| * where Mi is the ith pthread_mutex_t and CVi is the ith conditional |
| * variable.So, at the end of this loop, 26 threads are all waiting on |
| * seperate condvars and mutexes. |
| * - Wakes up thread at priority 10 (T1) by executing: |
| * pthread_mutex_lock(M1); |
| * pthread_cond_signal(CV1); |
| * pthread_mutex_unlock(M1); |
| * |
| * - Waits for all the worker threads to finish execution. |
| * T1 then wakes up T2 by signalling on the condvar CV2 and sets a flag |
| * called T1_after_wait to indicate that it is after the wait. It then |
| * checks if T2_after_wait has been set or not. If not, the test fails, |
| * else the process continues with other threads. The thread T1 expects |
| * T2_after_wait to be set as, the moment T1 signals on CV2, T2 is |
| * supposed to be scheduled (in accordance with priority preemption). |
| * |
| * USAGE: |
| * Use run_auto.sh script in current directory to build and run test. |
| * |
| * AUTHOR |
| * Dinakar Guniguntala <dino@us.ibm.com> |
| * |
| * HISTORY |
| * 2006-Jun-01: Initial version by Dinakar Guniguntala |
| * Changes from John Stultz and Vivek Pallantla |
| * |
| *****************************************************************************/ |
| |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <signal.h> |
| #include <time.h> |
| #include <pthread.h> |
| #include <sched.h> |
| #include <errno.h> |
| #include <sys/syscall.h> |
| #include <librttest.h> |
| |
| #define NUM_WORKERS 27 |
| #define CHECK_LIMIT 1 |
| |
| volatile int busy_threads = 0; |
| volatile int test_over = 0; |
| volatile int threads_running=0; |
| static int rt_threads = -1; |
| static int int_threads = 0; |
| static pthread_mutex_t bmutex = PTHREAD_MUTEX_INITIALIZER; |
| |
| static pthread_mutex_t mutex[NUM_WORKERS+1]; |
| static pthread_cond_t cond[NUM_WORKERS+1]; |
| static int t_after_wait[NUM_WORKERS]; |
| |
| static int ret = 0; |
| |
| pthread_barrier_t barrier; |
| |
| void usage(void) |
| { |
| rt_help(); |
| printf("prio-preempt specific options:\n"); |
| printf(" -i #: enable interrupter threads\n"); |
| printf(" -n# #: number of busy threads\n"); |
| } |
| |
| int parse_args(int c, char *v) |
| { |
| |
| int handled = 1; |
| switch (c) { |
| case 'h': |
| usage(); |
| exit(0); |
| case 'i': |
| int_threads = 1; |
| break; |
| case 'n': |
| rt_threads = atoi(v); |
| break; |
| default: |
| handled = 0; |
| break; |
| } |
| return handled; |
| } |
| |
| void *int_thread(void* arg) |
| { |
| intptr_t a = 0; |
| while (!test_over) { |
| /* do some busy work */ |
| if (!(a%4)) |
| a = a * 3; |
| else if (!(a%6)) |
| a = a /2; |
| else |
| a++; |
| usleep(20); |
| } |
| return (void*)a; |
| } |
| |
| void *busy_thread(void* arg) |
| { |
| struct sched_param sched_param; |
| int policy, mypri = 0, tid; |
| tid = (intptr_t)(((struct thread *) arg)->arg); |
| |
| if (pthread_getschedparam(pthread_self(), &policy, &sched_param) != 0) { |
| printf("ERR: Couldn't get pthread info \n"); |
| } else { |
| mypri = sched_param.sched_priority; |
| } |
| |
| pthread_mutex_lock(&bmutex); |
| busy_threads++; |
| printf("Busy Thread %d(%d): Running...\n", tid, mypri); |
| pthread_mutex_unlock(&bmutex); |
| |
| /* TODO: Add sched set affinity here */ |
| |
| /* Busy loop */ |
| while (!test_over); |
| |
| printf("Busy Thread %d(%d): Exiting\n", tid, mypri); |
| return NULL; |
| } |
| |
| void *worker_thread(void* arg) |
| { |
| struct sched_param sched_param; |
| int policy, rc, mypri = 0, tid, times = 0; |
| tid = (intptr_t)(((struct thread *) arg)->arg); |
| nsec_t pstart, pend; |
| |
| if (pthread_getschedparam(pthread_self(), &policy, &sched_param) != 0) { |
| printf("ERR: Couldn't get pthread info \n"); |
| } else { |
| mypri = sched_param.sched_priority; |
| } |
| /* check in */ |
| pthread_mutex_lock(&bmutex); |
| threads_running++; |
| pthread_mutex_unlock(&bmutex); |
| |
| /* block */ |
| rc = pthread_mutex_lock(&mutex[tid]); |
| if (tid == 0) |
| pthread_barrier_wait(&barrier); |
| rc = pthread_cond_wait(&cond[tid], &mutex[tid]); |
| rc = pthread_mutex_unlock(&mutex[tid]); |
| |
| debug(DBG_INFO, "%llu: Thread %d(%d) wakes up from sleep \n", rt_gettime(), tid, mypri); |
| |
| /*check if we're the last thread */ |
| if (tid == NUM_WORKERS-1) { |
| t_after_wait[tid] = 1; |
| pthread_mutex_lock(&bmutex); |
| threads_running--; |
| pthread_mutex_unlock(&bmutex); |
| return NULL; |
| } |
| |
| /* Signal next thread */ |
| rc = pthread_mutex_lock(&mutex[tid+1]); |
| rc = pthread_cond_signal(&cond[tid+1]); |
| debug(DBG_INFO, "%llu: Thread %d(%d): Sent signal (%d) to (%d)\n", rt_gettime(), tid, mypri, |
| rc, tid+1); |
| |
| pstart = pend = rt_gettime(); |
| rc = pthread_mutex_unlock(&mutex[tid+1]); |
| |
| debug(DBG_INFO, "%llu: Thread %d(%d) setting it's bit \n",rt_gettime(), tid, mypri); |
| |
| t_after_wait[tid] = 1; |
| |
| while (t_after_wait[tid+1] != 1) { |
| pend = rt_gettime(); |
| times++; |
| } |
| |
| if (times >= (int)pass_criteria) { |
| printf("Thread %d(%d): Non-Preempt limit reached. %llu ns latency\n", |
| tid, mypri, pend-pstart); |
| ret = 1; |
| } |
| |
| /* check out */ |
| pthread_mutex_lock(&bmutex); |
| threads_running--; |
| pthread_mutex_unlock(&bmutex); |
| |
| return NULL; |
| } |
| |
| void *master_thread(void* arg) |
| { |
| int i, pri_boost; |
| |
| pthread_barrier_init(&barrier, NULL, 2); |
| |
| /* start interrupter thread */ |
| if (int_threads) { |
| pri_boost = 90; |
| for (i = 0; i < rt_threads; i++) { |
| create_fifo_thread(int_thread, (void*)0, |
| sched_get_priority_min(SCHED_FIFO) + pri_boost); |
| } |
| } |
| |
| /* start the (N-1) busy threads */ |
| pri_boost = 80; |
| for (i = rt_threads; i > 1; i--) { |
| create_fifo_thread(busy_thread, (void*)(intptr_t)i, |
| sched_get_priority_min(SCHED_FIFO) + pri_boost); |
| } |
| |
| /* make sure children are started */ |
| while (busy_threads < (rt_threads-1)) |
| usleep(100); |
| |
| printf("Busy threads created!\n"); |
| |
| /* start NUM_WORKERS worker threads */ |
| for (i = 0, pri_boost = 10; i < NUM_WORKERS ; i++, pri_boost+=2) { |
| pthread_mutex_init(&mutex[i], NULL); |
| pthread_cond_init(&cond[i], NULL); |
| create_fifo_thread(worker_thread, (void*)(intptr_t)i, |
| sched_get_priority_min(SCHED_FIFO) + pri_boost); |
| } |
| |
| printf("Worker threads created\n"); |
| /* Let the worker threads wait on the cond vars */ |
| while (threads_running < NUM_WORKERS) |
| usleep(100); |
| |
| /* Ensure the first worker has called cond_wait */ |
| pthread_barrier_wait(&barrier); |
| |
| printf("Signaling first thread\n"); |
| pthread_mutex_lock(&mutex[0]); |
| pthread_cond_signal(&cond[0]); |
| pthread_mutex_unlock(&mutex[0]); |
| |
| while (threads_running) |
| usleep(500000); /* this period greatly affects the number of failures! */ |
| |
| test_over = 1; |
| return NULL; |
| } |
| |
| int main(int argc, char* argv[]) |
| { |
| int pri_boost,numcpus; |
| setup(); |
| |
| pass_criteria = CHECK_LIMIT; |
| rt_init("hin:", parse_args, argc, argv); |
| |
| numcpus = sysconf(_SC_NPROCESSORS_ONLN); |
| |
| /* Max no. of busy threads should always be less than/equal the no. of cpus |
| Otherwise, the box will hang */ |
| |
| if (rt_threads == -1 || rt_threads > numcpus) { |
| rt_threads = numcpus; |
| printf("Maximum busy thread count(%d), " |
| "should not exceed number of cpus(%d)\n", rt_threads, numcpus); |
| printf("Using %d\n", numcpus); |
| } |
| |
| /* Test boilder plate: title and parameters*/ |
| printf("\n-------------------\n"); |
| printf("Priority Preemption\n"); |
| printf("-------------------\n\n"); |
| printf("Busy Threads: %d\n", rt_threads); |
| printf("Interrupter Threads: %s\n", int_threads ? "Enabled" : "Disabled"); |
| printf("Worker Threads: %d\n\n", NUM_WORKERS); |
| |
| pri_boost = 81; |
| create_fifo_thread(master_thread, (void*)0, |
| sched_get_priority_min(SCHED_FIFO) + pri_boost); |
| |
| /* wait for threads to complete */ |
| join_threads(); |
| |
| printf("\nCriteria: All threads appropriately preempted within %d loop(s)\n", (int)pass_criteria); |
| printf("Result: %s\n", ret ? "FAIL" : "PASS"); |
| return ret; |
| } |