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/smp.h>
45 #include <vppinfra/time.h>
46 #include <vppinfra/timer.h>
47 #include <vppinfra/error.h>
56 /* Vector of currently unexpired timers. */
57 static timer_callback_t *timers;
59 /* Convert time from 64bit floating format to struct timeval. */
61 f64_to_tv (f64 t, struct timeval *tv)
64 tv->tv_usec = 1e6 * (t - tv->tv_sec);
65 while (tv->tv_usec >= 1000000)
67 tv->tv_usec -= 1000000;
72 /* Sort timers so that timer soonest to expire is at end. */
74 timer_compare (const void *_a, const void *_b)
76 const timer_callback_t *a = _a;
77 const timer_callback_t *b = _b;
78 f64 dt = b->time - a->time;
79 return dt < 0 ? -1 : (dt > 0 ? +1 : 0);
83 sort_timers (timer_callback_t * timers)
85 qsort (timers, vec_len (timers), sizeof (timers[0]), timer_compare);
88 #define TIMER_SIGNAL SIGALRM
90 /* Don't bother set timer if time different is less than this value. */
91 /* We would like to initialize this to 0.75 / (f64) HZ,
92 * but HZ may not be a compile-time constant on some systems,
93 * so instead we do the initialization before first use.
95 static f64 time_resolution;
97 /* Interrupt handler. Call functions for all expired timers.
98 Set time for next timer interrupt. */
100 timer_interrupt (int signum)
102 f64 now = unix_time_now ();
108 if (vec_len (timers) <= 0)
111 /* Consider last (earliest) timer in reverse sorted
112 vector of pending timers. */
113 t = vec_end (timers) - 1;
115 ASSERT (now >= 0 && finite (now));
117 /* Time difference between when timer goes off and now. */
120 /* If timer is within threshold of going off
121 call user's callback. */
122 if (dt <= time_resolution && finite (dt))
124 _vec_len (timers) -= 1;
125 (*t->func) (t->arg, -dt);
129 /* Set timer for to go off in future. */
130 struct itimerval itv;
131 memset (&itv, 0, sizeof (itv));
132 f64_to_tv (dt, &itv.it_value);
133 if (setitimer (ITIMER_REAL, &itv, 0) < 0)
134 clib_unix_error ("sititmer");
141 timer_block (sigset_t * save)
143 sigset_t block_timer;
145 memset (&block_timer, 0, sizeof (block_timer));
146 sigaddset (&block_timer, TIMER_SIGNAL);
147 sigprocmask (SIG_BLOCK, &block_timer, save);
151 timer_unblock (sigset_t * save)
153 sigprocmask (SIG_SETMASK, save, 0);
156 /* Arrange for function to be called some time,
157 roughly equal to dt seconds, in the future. */
159 timer_call (timer_func_t * func, any arg, f64 dt)
164 /* Install signal handler on first call. */
165 static word signal_installed = 0;
167 if (!signal_installed)
171 /* Initialize time_resolution before first call to timer_interrupt */
172 time_resolution = 0.75 / (f64) HZ;
174 memset (&sa, 0, sizeof (sa));
175 sa.sa_handler = timer_interrupt;
177 if (sigaction (TIMER_SIGNAL, &sa, 0) < 0)
178 clib_panic ("sigaction");
180 signal_installed = 1;
186 vec_add2 (timers, t, 1);
188 t->time = unix_time_now () + dt;
193 word reset_timer = vec_len (timers) == 1;
195 if (_vec_len (timers) > 1)
197 reset_timer += t->time < (t - 1)->time;
198 sort_timers (timers);
202 timer_interrupt (TIMER_SIGNAL);
205 timer_unblock (&save);
210 #include <vppinfra/random.h>
212 /* Compute average delay of function calls to foo.
213 If this is a small number over a lot of iterations we know
214 the code is working. */
216 static f64 ave_delay = 0;
217 static word ave_delay_count = 0;
223 ave_delay_count += 1;
228 f64 time_requested, time_called;
231 static f64 foo_base_time = 0;
232 static foo_t *foos = 0;
235 foo (any arg, f64 delay)
237 foos[arg].time_called = unix_time_now () - foo_base_time;
248 bar (any arg, f64 delay)
250 bar_t *b = (bar_t *) arg;
252 fformat (stdout, "bar %d delay %g\n", b->count++, delay);
255 if (b->count < b->limit)
256 timer_call (bar, arg, random_f64 ());
260 main (int argc, char *argv[])
262 word i, n = atoi (argv[1]);
263 word run_foo = argc > 2;
264 bar_t b = { limit:10 };
270 time_limit = atof (argv[2]);
272 vec_resize (foos, n);
273 for (i = 0; i < n; i++)
275 foos[i].time_requested = time_limit * random_f64 ();
276 foos[i].time_called = 1e100;
279 foo_base_time = unix_time_now ();
280 for (i = 0; i < n; i++)
281 timer_call (foo, i, foos[i].time_requested);
284 timer_call (bar, (any) & b, random_f64 ());
286 while (vec_len (timers) > 0)
289 if (vec_len (foos) > 0)
291 f64 min = 1e100, max = -min;
292 f64 ave = 0, rms = 0;
294 for (i = 0; i < n; i++)
296 f64 dt = foos[i].time_requested - foos[i].time_called;
305 rms = sqrt (rms / n - ave * ave);
306 fformat (stdout, "error min %g max %g ave %g +- %g\n", min, max, ave,
310 fformat (stdout, "%d function calls, ave. timer delay %g secs\n",
311 ave_delay_count, ave_delay / ave_delay_count);
318 * fd.io coding-style-patch-verification: ON
321 * eval: (c-set-style "gnu")