4 This file is part of PulseAudio.
6 Copyright 2004-2006 Lennart Poettering
8 PulseAudio is free software; you can redistribute it and/or modify
9 it under the terms of the GNU Lesser General Public License as
10 published by the Free Software Foundation; either version 2 of the
11 License, or (at your option) any later version.
13 PulseAudio is distributed in the hope that it will be useful, but
14 WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 General Public License for more details.
18 You should have received a copy of the GNU Lesser General Public
19 License along with PulseAudio; if not, write to the Free Software
20 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
28 #include <pulse/error.h>
30 #include <pulsecore/core-util.h>
31 #include <pulsecore/core-error.h>
32 #include <pulsecore/log.h>
46 #ifdef HAVE_SYS_RESOURCE_H
47 #include <sys/resource.h>
50 /* This module implements a watchdog that makes sure that the current
51 * process doesn't consume more than 70% CPU time for 10 seconds. This
52 * is very useful when using SCHED_FIFO scheduling which effectively
53 * disables multitasking. */
55 /* Method of operation: Using SIGXCPU a signal handler is called every
56 * 10s process CPU time. That function checks if less than 14s system
57 * time have passed. In that case, it tries to contact the main event
58 * loop through a pipe. After two additional seconds it is checked
59 * whether the main event loop contact was successful. If not, the
60 * program is terminated forcibly. */
62 /* Utilize this much CPU time at maximum */
63 #define CPUTIME_PERCENT 70
66 #define CPUTIME_INTERVAL_SOFT (10)
68 /* Recheck after 5s */
69 #define CPUTIME_INTERVAL_HARD (5)
71 /* Time of the last CPU load check */
72 static time_t last_time = 0;
74 /* Pipe for communicating with the main loop */
75 static int the_pipe[2] = {-1, -1};
77 /* Main event loop and IO event for the FIFO */
78 static pa_mainloop_api *api = NULL;
79 static pa_io_event *io_event = NULL;
81 /* Saved sigaction struct for SIGXCPU */
82 static struct sigaction sigaction_prev;
84 /* Nonzero after pa_cpu_limit_init() */
85 static int installed = 0;
87 /* The current state of operation */
89 PHASE_IDLE, /* Normal state */
90 PHASE_SOFT /* After CPU overload has been detected */
93 /* Reset the SIGXCPU timer to the next t seconds */
94 static void reset_cpu_time(int t) {
100 /* Get the current CPU time of the current process */
101 r = getrusage(RUSAGE_SELF, &ru);
104 n = ru.ru_utime.tv_sec + ru.ru_stime.tv_sec + t;
106 r = getrlimit(RLIMIT_CPU, &rl);
110 r = setrlimit(RLIMIT_CPU, &rl);
114 /* A simple, thread-safe puts() work-alike */
115 static void write_err(const char *p) {
116 pa_loop_write(2, p, strlen(p), NULL);
119 /* The signal handler, called on every SIGXCPU */
120 static void signal_handler(int sig) {
121 assert(sig == SIGXCPU);
123 if (phase == PHASE_IDLE) {
126 #ifdef PRINT_CPU_LOAD
132 #ifdef PRINT_CPU_LOAD
133 snprintf(t, sizeof(t), "Using %0.1f%% CPU\n", (double)CPUTIME_INTERVAL_SOFT/(now-last_time)*100);
137 if (CPUTIME_INTERVAL_SOFT >= ((now-last_time)*(double)CPUTIME_PERCENT/100)) {
138 static const char c = 'X';
140 write_err("Soft CPU time limit exhausted, terminating.\n");
142 /* Try a soft cleanup */
143 write(the_pipe[1], &c, sizeof(c));
145 reset_cpu_time(CPUTIME_INTERVAL_HARD);
149 /* Everything's fine */
150 reset_cpu_time(CPUTIME_INTERVAL_SOFT);
154 } else if (phase == PHASE_SOFT) {
155 write_err("Hard CPU time limit exhausted, terminating forcibly.\n");
156 _exit(1); /* Forced exit */
160 /* Callback for IO events on the FIFO */
161 static void callback(pa_mainloop_api*m, pa_io_event*e, int fd, pa_io_event_flags_t f, void *userdata) {
163 assert(m && e && f == PA_IO_EVENT_INPUT && e == io_event && fd == the_pipe[0]);
164 pa_read(the_pipe[0], &c, sizeof(c), NULL);
165 m->quit(m, 1); /* Quit the main loop */
168 /* Initializes CPU load limiter */
169 int pa_cpu_limit_init(pa_mainloop_api *m) {
171 assert(m && !api && !io_event && the_pipe[0] == -1 && the_pipe[1] == -1 && !installed);
175 /* Prepare the main loop pipe */
176 if (pipe(the_pipe) < 0) {
177 pa_log("pipe() failed: %s", pa_cstrerror(errno));
181 pa_make_nonblock_fd(the_pipe[0]);
182 pa_make_nonblock_fd(the_pipe[1]);
183 pa_fd_set_cloexec(the_pipe[0], 1);
184 pa_fd_set_cloexec(the_pipe[1], 1);
187 io_event = api->io_new(m, the_pipe[0], PA_IO_EVENT_INPUT, callback, NULL);
191 /* Install signal handler for SIGXCPU */
192 memset(&sa, 0, sizeof(sa));
193 sa.sa_handler = signal_handler;
194 sigemptyset(&sa.sa_mask);
195 sa.sa_flags = SA_RESTART;
197 if (sigaction(SIGXCPU, &sa, &sigaction_prev) < 0) {
204 reset_cpu_time(CPUTIME_INTERVAL_SOFT);
209 /* Shutdown CPU load limiter */
210 void pa_cpu_limit_done(void) {
215 api->io_free(io_event);
220 if (the_pipe[0] >= 0)
222 if (the_pipe[1] >= 0)
224 the_pipe[0] = the_pipe[1] = -1;
227 r = sigaction(SIGXCPU, &sigaction_prev, NULL);
233 #else /* HAVE_SIGXCPU */
235 int pa_cpu_limit_init(PA_GCC_UNUSED pa_mainloop_api *m) {
239 void pa_cpu_limit_done(void) {