2 * Copyright (c) 2015 Cisco and/or its affiliates.
3 * Licensed under the Apache License, Version 2.0 (the "License");
4 * you may not use this file except in compliance with the License.
5 * You may obtain a copy of the License at:
7 * http://www.apache.org/licenses/LICENSE-2.0
9 * Unless required by applicable law or agreed to in writing, software
10 * distributed under the License is distributed on an "AS IS" BASIS,
11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 * See the License for the specific language governing permissions and
13 * limitations under the License.
16 Copyright (c) 2001, 2002, 2003 Eliot Dresselhaus
18 Permission is hereby granted, free of charge, to any person obtaining
19 a copy of this software and associated documentation files (the
20 "Software"), to deal in the Software without restriction, including
21 without limitation the rights to use, copy, modify, merge, publish,
22 distribute, sublicense, and/or sell copies of the Software, and to
23 permit persons to whom the Software is furnished to do so, subject to
24 the following conditions:
26 The above copyright notice and this permission notice shall be
27 included in all copies or substantial portions of the Software.
29 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
30 EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
31 MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
32 NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
33 LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
34 OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
35 WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
41 #include <sys/param.h>
43 #include <vppinfra/vec.h>
44 #include <vppinfra/time.h>
45 #include <vppinfra/timer.h>
46 #include <vppinfra/error.h>
54 /* Vector of currently unexpired timers. */
55 static timer_callback_t * timers;
57 /* Convert time from 64bit floating format to struct timeval. */
58 always_inline void f64_to_tv (f64 t, struct timeval * tv)
61 tv->tv_usec = 1e6*(t - tv->tv_sec);
62 while (tv->tv_usec >= 1000000)
64 tv->tv_usec -= 1000000;
69 /* Sort timers so that timer soonest to expire is at end. */
70 static int timer_compare (const void * _a, const void * _b)
72 const timer_callback_t * a = _a;
73 const timer_callback_t * b = _b;
74 f64 dt = b->time - a->time;
75 return dt < 0 ? -1 : (dt > 0 ? +1 : 0);
78 static inline void sort_timers (timer_callback_t * timers)
79 { qsort (timers, vec_len (timers), sizeof (timers[0]), timer_compare); }
81 #define TIMER_SIGNAL SIGALRM
83 /* Don't bother set timer if time different is less than this value. */
84 /* We would like to initialize this to 0.75 / (f64) HZ,
85 * but HZ may not be a compile-time constant on some systems,
86 * so instead we do the initialization before first use.
88 static f64 time_resolution;
90 /* Interrupt handler. Call functions for all expired timers.
91 Set time for next timer interrupt. */
92 static void timer_interrupt (int signum)
94 f64 now = unix_time_now ();
100 if (vec_len (timers) <= 0)
103 /* Consider last (earliest) timer in reverse sorted
104 vector of pending timers. */
105 t = vec_end (timers) - 1;
107 ASSERT (now >= 0 && finite (now));
109 /* Time difference between when timer goes off and now. */
112 /* If timer is within threshold of going off
113 call user's callback. */
114 if (dt <= time_resolution && finite (dt))
116 _vec_len (timers) -= 1;
117 (* t->func) (t->arg, -dt);
121 /* Set timer for to go off in future. */
122 struct itimerval itv;
123 memset (&itv, 0, sizeof (itv));
124 f64_to_tv (dt, &itv.it_value);
125 if (setitimer (ITIMER_REAL, &itv, 0) < 0)
126 clib_unix_error ("sititmer");
132 void timer_block (sigset_t * save)
134 sigset_t block_timer;
136 memset (&block_timer, 0, sizeof (block_timer));
137 sigaddset (&block_timer, TIMER_SIGNAL);
138 sigprocmask (SIG_BLOCK, &block_timer, save);
141 void timer_unblock (sigset_t * save)
142 { sigprocmask (SIG_SETMASK, save, 0); }
144 /* Arrange for function to be called some time,
145 roughly equal to dt seconds, in the future. */
146 void timer_call (timer_func_t * func, any arg, f64 dt)
148 timer_callback_t * t;
151 /* Install signal handler on first call. */
152 static word signal_installed = 0;
154 if (! signal_installed)
158 /* Initialize time_resolution before first call to timer_interrupt */
159 time_resolution = 0.75 / (f64) HZ;
161 sa.sa_handler = timer_interrupt;
164 if (sigaction (TIMER_SIGNAL, &sa, 0) < 0)
165 clib_panic ("sigaction");
167 signal_installed = 1;
173 vec_add2 (timers, t, 1);
175 t->time = unix_time_now () + dt;
180 word reset_timer = vec_len (timers) == 1;
182 if (_vec_len (timers) > 1)
184 reset_timer += t->time < (t-1)->time;
185 sort_timers (timers);
189 timer_interrupt (TIMER_SIGNAL);
192 timer_unblock (&save);
197 #include <vppinfra/random.h>
199 /* Compute average delay of function calls to foo.
200 If this is a small number over a lot of iterations we know
201 the code is working. */
203 static f64 ave_delay = 0;
204 static word ave_delay_count = 0;
206 always_inline update (f64 delay)
209 ave_delay_count += 1;
213 f64 time_requested, time_called;
216 static f64 foo_base_time = 0;
217 static foo_t * foos = 0;
219 void foo (any arg, f64 delay)
221 foos[arg].time_called = unix_time_now () - foo_base_time;
230 void bar (any arg, f64 delay)
232 bar_t * b = (bar_t *) arg;
234 fformat (stdout, "bar %d delay %g\n", b->count++, delay);
237 if (b->count < b->limit)
238 timer_call (bar, arg, random_f64 ());
241 int main (int argc, char * argv[])
243 word i, n = atoi (argv[1]);
244 word run_foo = argc > 2;
245 bar_t b = {limit: 10};
251 time_limit = atof (argv[2]);
253 vec_resize (foos, n);
254 for (i = 0; i < n; i++)
256 foos[i].time_requested = time_limit * random_f64 ();
257 foos[i].time_called = 1e100;
260 foo_base_time = unix_time_now ();
261 for (i = 0; i < n; i++)
262 timer_call (foo, i, foos[i].time_requested);
265 timer_call (bar, (any) &b, random_f64 ());
267 while (vec_len (timers) > 0)
270 if (vec_len (foos) > 0)
272 f64 min = 1e100, max = -min;
273 f64 ave = 0, rms = 0;
275 for (i = 0; i < n; i++)
277 f64 dt = foos[i].time_requested - foos[i].time_called;
286 rms = sqrt (rms / n - ave*ave);
287 fformat (stdout, "error min %g max %g ave %g +- %g\n", min, max, ave, rms);
290 fformat (stdout, "%d function calls, ave. timer delay %g secs\n",
291 ave_delay_count, ave_delay / ave_delay_count);