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>
55 /* Vector of currently unexpired timers. */
56 static timer_callback_t *timers;
58 /* Convert time from 64bit floating format to struct timeval. */
60 f64_to_tv (f64 t, struct timeval *tv)
63 tv->tv_usec = 1e6 * (t - tv->tv_sec);
64 while (tv->tv_usec >= 1000000)
66 tv->tv_usec -= 1000000;
71 /* Sort timers so that timer soonest to expire is at end. */
73 timer_compare (const void *_a, const void *_b)
75 const timer_callback_t *a = _a;
76 const timer_callback_t *b = _b;
77 f64 dt = b->time - a->time;
78 return dt < 0 ? -1 : (dt > 0 ? +1 : 0);
82 sort_timers (timer_callback_t * timers)
84 qsort (timers, vec_len (timers), sizeof (timers[0]), timer_compare);
87 #define TIMER_SIGNAL SIGALRM
89 /* Don't bother set timer if time different is less than this value. */
90 /* We would like to initialize this to 0.75 / (f64) HZ,
91 * but HZ may not be a compile-time constant on some systems,
92 * so instead we do the initialization before first use.
94 static f64 time_resolution;
96 /* Interrupt handler. Call functions for all expired timers.
97 Set time for next timer interrupt. */
99 timer_interrupt (int signum)
101 f64 now = unix_time_now ();
107 if (vec_len (timers) <= 0)
110 /* Consider last (earliest) timer in reverse sorted
111 vector of pending timers. */
112 t = vec_end (timers) - 1;
114 ASSERT (now >= 0 && finite (now));
116 /* Time difference between when timer goes off and now. */
119 /* If timer is within threshold of going off
120 call user's callback. */
121 if (dt <= time_resolution && finite (dt))
123 _vec_len (timers) -= 1;
124 (*t->func) (t->arg, -dt);
128 /* Set timer for to go off in future. */
129 struct itimerval itv;
130 memset (&itv, 0, sizeof (itv));
131 f64_to_tv (dt, &itv.it_value);
132 if (setitimer (ITIMER_REAL, &itv, 0) < 0)
133 clib_unix_error ("sititmer");
140 timer_block (sigset_t * save)
142 sigset_t block_timer;
144 memset (&block_timer, 0, sizeof (block_timer));
145 sigaddset (&block_timer, TIMER_SIGNAL);
146 sigprocmask (SIG_BLOCK, &block_timer, save);
150 timer_unblock (sigset_t * save)
152 sigprocmask (SIG_SETMASK, save, 0);
155 /* Arrange for function to be called some time,
156 roughly equal to dt seconds, in the future. */
158 timer_call (timer_func_t * func, any arg, f64 dt)
163 /* Install signal handler on first call. */
164 static word signal_installed = 0;
166 if (!signal_installed)
170 /* Initialize time_resolution before first call to timer_interrupt */
171 time_resolution = 0.75 / (f64) HZ;
173 memset (&sa, 0, sizeof (sa));
174 sa.sa_handler = timer_interrupt;
176 if (sigaction (TIMER_SIGNAL, &sa, 0) < 0)
177 clib_panic ("sigaction");
179 signal_installed = 1;
185 vec_add2 (timers, t, 1);
187 t->time = unix_time_now () + dt;
192 word reset_timer = vec_len (timers) == 1;
194 if (_vec_len (timers) > 1)
196 reset_timer += t->time < (t - 1)->time;
197 sort_timers (timers);
201 timer_interrupt (TIMER_SIGNAL);
204 timer_unblock (&save);
209 #include <vppinfra/random.h>
211 /* Compute average delay of function calls to foo.
212 If this is a small number over a lot of iterations we know
213 the code is working. */
215 static f64 ave_delay = 0;
216 static word ave_delay_count = 0;
222 ave_delay_count += 1;
227 f64 time_requested, time_called;
230 static f64 foo_base_time = 0;
231 static foo_t *foos = 0;
234 foo (any arg, f64 delay)
236 foos[arg].time_called = unix_time_now () - foo_base_time;
247 bar (any arg, f64 delay)
249 bar_t *b = (bar_t *) arg;
251 fformat (stdout, "bar %d delay %g\n", b->count++, delay);
254 if (b->count < b->limit)
255 timer_call (bar, arg, random_f64 ());
259 main (int argc, char *argv[])
261 word i, n = atoi (argv[1]);
262 word run_foo = argc > 2;
263 bar_t b = { limit:10 };
269 time_limit = atof (argv[2]);
271 vec_resize (foos, n);
272 for (i = 0; i < n; i++)
274 foos[i].time_requested = time_limit * random_f64 ();
275 foos[i].time_called = 1e100;
278 foo_base_time = unix_time_now ();
279 for (i = 0; i < n; i++)
280 timer_call (foo, i, foos[i].time_requested);
283 timer_call (bar, (any) & b, random_f64 ());
285 while (vec_len (timers) > 0)
288 if (vec_len (foos) > 0)
290 f64 min = 1e100, max = -min;
291 f64 ave = 0, rms = 0;
293 for (i = 0; i < n; i++)
295 f64 dt = foos[i].time_requested - foos[i].time_called;
304 rms = sqrt (rms / n - ave * ave);
305 fformat (stdout, "error min %g max %g ave %g +- %g\n", min, max, ave,
309 fformat (stdout, "%d function calls, ave. timer delay %g secs\n",
310 ave_delay_count, ave_delay / ave_delay_count);
317 * fd.io coding-style-patch-verification: ON
320 * eval: (c-set-style "gnu")