timerlr-generic.cpp@ 96407

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1	/* $Id: timerlr-generic.cpp 96407 2022-08-22 17:43:14Z vboxsync $ */
2	/** @file
3	* IPRT - Low Resolution Timers, Generic.
4	*
5	* This code is more or less identical to timer-generic.cpp, so
6	* bugfixes goes into both files.
7	*/
8
9	/*
10	* Copyright (C) 2006-2022 Oracle and/or its affiliates.
11	*
12	* This file is part of VirtualBox base platform packages, as
13	* available from https://www.virtualbox.org.
14	*
15	* This program is free software; you can redistribute it and/or
16	* modify it under the terms of the GNU General Public License
17	* as published by the Free Software Foundation, in version 3 of the
18	* License.
19	*
20	* This program is distributed in the hope that it will be useful, but
21	* WITHOUT ANY WARRANTY; without even the implied warranty of
22	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
23	* General Public License for more details.
24	*
25	* You should have received a copy of the GNU General Public License
26	* along with this program; if not, see <https://www.gnu.org/licenses>.
27	*
28	* The contents of this file may alternatively be used under the terms
29	* of the Common Development and Distribution License Version 1.0
30	* (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
31	* in the VirtualBox distribution, in which case the provisions of the
32	* CDDL are applicable instead of those of the GPL.
33	*
34	* You may elect to license modified versions of this file under the
35	* terms and conditions of either the GPL or the CDDL or both.
36	*
37	* SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
38	*/
39
40
41	/*********************************************************************************************************************************
42	* Header Files *
43	*********************************************************************************************************************************/
44	#include <iprt/timer.h>
45	#include "internal/iprt.h"
46
47	#include <iprt/thread.h>
48	#include <iprt/err.h>
49	#include <iprt/assert.h>
50	#include <iprt/alloc.h>
51	#include <iprt/asm.h>
52	#include <iprt/semaphore.h>
53	#include <iprt/time.h>
54	#include <iprt/log.h>
55	#include "internal/magics.h"
56
57
58	/*********************************************************************************************************************************
59	* Defined Constants And Macros *
60	*********************************************************************************************************************************/
61	/** The smallest interval for low resolution timers. */
62	#define RTTIMERLR_MIN_INTERVAL RT_NS_100MS
63
64
65	/*********************************************************************************************************************************
66	* Structures and Typedefs *
67	*********************************************************************************************************************************/
68	/**
69	* The internal representation of a timer handle.
70	*/
71	typedef struct RTTIMERLRINT
72	{
73	/** Magic.
74	* This is RTTIMERRT_MAGIC, but changes to something else before the timer
75	* is destroyed to indicate clearly that thread should exit. */
76	uint32_t volatile u32Magic;
77	/** Flag indicating the timer is suspended. */
78	bool volatile fSuspended;
79	/** Flag indicating that the timer has been destroyed. */
80	bool volatile fDestroyed;
81	/** Set when the thread is blocked. */
82	bool volatile fBlocked;
83	bool fPadding;
84	/** The timer interval. 0 if one-shot. */
85	uint64_t volatile u64NanoInterval;
86	/** The start of the current run (ns).
87	* This is used to calculate when the timer ought to fire the next time. */
88	uint64_t volatile u64StartTS;
89	/** The start of the current run (ns).
90	* This is used to calculate when the timer ought to fire the next time. */
91	uint64_t volatile u64NextTS;
92	/** The current tick number (since u64StartTS). */
93	uint64_t volatile iTick;
94
95	/** Callback. */
96	PFNRTTIMERLR pfnTimer;
97	/** User argument. */
98	void *pvUser;
99	/** The timer thread. */
100	RTTHREAD hThread;
101	/** Event semaphore on which the thread is blocked. */
102	RTSEMEVENT hEvent;
103	} RTTIMERLRINT;
104	typedef RTTIMERLRINT *PRTTIMERLRINT;
105
106
107	/*********************************************************************************************************************************
108	* Internal Functions *
109	*********************************************************************************************************************************/
110	static DECLCALLBACK(int) rtTimerLRThread(RTTHREAD hThread, void *pvUser);
111
112
113	RTDECL(int) RTTimerLRCreateEx(RTTIMERLR phTimerLR, uint64_t u64NanoInterval, uint32_t fFlags, PFNRTTIMERLR pfnTimer, void pvUser)
114	{
115	AssertPtr(phTimerLR);
116	*phTimerLR = NIL_RTTIMERLR;
117
118	/*
119	* We don't support the fancy MP features, nor intervals lower than 100 ms.
120	*/
121	AssertReturn(!(fFlags & RTTIMER_FLAGS_CPU_SPECIFIC), VERR_NOT_SUPPORTED);
122	AssertReturn(!u64NanoInterval \|\| u64NanoInterval >= RTTIMERLR_MIN_INTERVAL, VERR_OUT_OF_RANGE);
123
124	/*
125	* Allocate and initialize the timer handle.
126	*/
127	PRTTIMERLRINT pThis = (PRTTIMERLRINT)RTMemAlloc(sizeof(*pThis));
128	if (!pThis)
129	return VERR_NO_MEMORY;
130
131	pThis->u32Magic = RTTIMERLR_MAGIC;
132	pThis->fSuspended = true;
133	pThis->fDestroyed = false;
134	pThis->fBlocked = false;
135	pThis->fPadding = false;
136	pThis->pfnTimer = pfnTimer;
137	pThis->pvUser = pvUser;
138	pThis->hThread = NIL_RTTHREAD;
139	pThis->hEvent = NIL_RTSEMEVENT;
140	pThis->u64NanoInterval = u64NanoInterval;
141	pThis->u64StartTS = 0;
142
143	int rc = RTSemEventCreate(&pThis->hEvent);
144	if (RT_SUCCESS(rc))
145	{
146	rc = RTThreadCreate(&pThis->hThread, rtTimerLRThread, pThis, 0, RTTHREADTYPE_TIMER, RTTHREADFLAGS_WAITABLE, "TimerLR");
147	if (RT_SUCCESS(rc))
148	{
149	*phTimerLR = pThis;
150	return VINF_SUCCESS;
151	}
152
153	pThis->u32Magic = 0;
154	RTSemEventDestroy(pThis->hEvent);
155	pThis->hEvent = NIL_RTSEMEVENT;
156	}
157	RTMemFree(pThis);
158
159	return rc;
160	}
161	RT_EXPORT_SYMBOL(RTTimerLRCreateEx);
162
163
164	RTDECL(int) RTTimerLRDestroy(RTTIMERLR hTimerLR)
165	{
166	/*
167	* Validate input, NIL is fine though.
168	*/
169	if (hTimerLR == NIL_RTTIMERLR)
170	return VINF_SUCCESS;
171	PRTTIMERLRINT pThis = hTimerLR;
172	AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
173	AssertReturn(pThis->u32Magic == RTTIMERLR_MAGIC, VERR_INVALID_HANDLE);
174	AssertReturn(!pThis->fDestroyed, VERR_INVALID_HANDLE);
175
176	/*
177	* If the timer is active, we stop and destruct it in one go, to avoid
178	* unnecessary waiting for the next tick. If it's suspended we can safely
179	* set the destroy flag and signal it.
180	*/
181	RTTHREAD hThread = pThis->hThread;
182	if (!pThis->fSuspended)
183	ASMAtomicWriteBool(&pThis->fSuspended, true);
184	ASMAtomicWriteBool(&pThis->fDestroyed, true);
185	int rc = RTSemEventSignal(pThis->hEvent);
186	if (rc == VERR_ALREADY_POSTED)
187	rc = VINF_SUCCESS;
188	AssertRC(rc);
189
190	RTThreadWait(hThread, 250, NULL);
191	return VINF_SUCCESS;
192	}
193	RT_EXPORT_SYMBOL(RTTimerLRDestroy);
194
195
196	/**
197	* Internal worker fro RTTimerLRStart and RTTiemrLRChangeInterval.
198	*/
199	static int rtTimerLRStart(PRTTIMERLRINT pThis, uint64_t u64First)
200	{
201	if (!pThis->fSuspended)
202	return VERR_TIMER_ACTIVE;
203
204	/*
205	* Calc when it should start firing and give the thread a kick so it get going.
206	*/
207	u64First += RTTimeNanoTS();
208	ASMAtomicWriteU64(&pThis->iTick, 0);
209	ASMAtomicWriteU64(&pThis->u64StartTS, u64First);
210	ASMAtomicWriteU64(&pThis->u64NextTS, u64First);
211	ASMAtomicWriteBool(&pThis->fSuspended, false);
212	int rc = RTSemEventSignal(pThis->hEvent);
213	if (rc == VERR_ALREADY_POSTED)
214	rc = VINF_SUCCESS;
215	AssertRC(rc);
216	return rc;
217	}
218
219
220	RTDECL(int) RTTimerLRStart(RTTIMERLR hTimerLR, uint64_t u64First)
221	{
222	/*
223	* Validate input.
224	*/
225	PRTTIMERLRINT pThis = hTimerLR;
226	AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
227	AssertReturn(pThis->u32Magic == RTTIMERLR_MAGIC, VERR_INVALID_HANDLE);
228	AssertReturn(!pThis->fDestroyed, VERR_INVALID_HANDLE);
229	AssertReturn(!u64First \|\| u64First >= RTTIMERLR_MIN_INTERVAL, VERR_OUT_OF_RANGE);
230
231	/*
232	* Do the job.
233	*/
234	return rtTimerLRStart(pThis, u64First);
235	}
236	RT_EXPORT_SYMBOL(RTTimerLRStart);
237
238
239	/**
240	* Internal worker for RTTimerLRStop and RTTimerLRChangeInterval
241	*/
242	static int rtTimerLRStop(PRTTIMERLRINT pThis, bool fSynchronous)
243	{
244	/*
245	* Fail if already suspended.
246	*/
247	if (pThis->fSuspended)
248	return VERR_TIMER_SUSPENDED;
249
250	/*
251	* Mark it as suspended and kick the thread.
252	* It's simpler to always reset the thread user semaphore, so we do that first.
253	*/
254	int rc = RTThreadUserReset(pThis->hThread);
255	AssertRC(rc);
256
257	ASMAtomicWriteBool(&pThis->fSuspended, true);
258	rc = RTSemEventSignal(pThis->hEvent);
259	if (rc == VERR_ALREADY_POSTED)
260	rc = VINF_SUCCESS;
261	AssertRC(rc);
262
263	/*
264	* Wait for the thread to stop running if synchronous.
265	*/
266	if (fSynchronous && RT_SUCCESS(rc))
267	{
268	rc = RTThreadUserWait(pThis->hThread, RT_MS_1MIN);
269	AssertRC(rc);
270	}
271
272	return rc;
273	}
274
275
276	RTDECL(int) RTTimerLRStop(RTTIMERLR hTimerLR)
277	{
278	/*
279	* Validate input.
280	*/
281	PRTTIMERLRINT pThis = hTimerLR;
282	AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
283	AssertReturn(pThis->u32Magic == RTTIMERLR_MAGIC, VERR_INVALID_HANDLE);
284	AssertReturn(!pThis->fDestroyed, VERR_INVALID_HANDLE);
285
286	/*
287	* Do the job.
288	*/
289	return rtTimerLRStop(pThis, false);
290	}
291	RT_EXPORT_SYMBOL(RTTimerLRStop);
292
293
294	RTDECL(int) RTTimerLRChangeInterval(RTTIMERLR hTimerLR, uint64_t u64NanoInterval)
295	{
296	/*
297	* Validate input.
298	*/
299	PRTTIMERLRINT pThis = hTimerLR;
300	AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
301	AssertReturn(pThis->u32Magic == RTTIMERLR_MAGIC, VERR_INVALID_HANDLE);
302	AssertReturn(!pThis->fDestroyed, VERR_INVALID_HANDLE);
303	AssertReturn(!u64NanoInterval \|\| u64NanoInterval >= RTTIMERLR_MIN_INTERVAL, VERR_OUT_OF_RANGE);
304
305	/*
306	* Do the job accoring to state and caller.
307	*/
308	int rc;
309	if (pThis->fSuspended)
310	{
311	/* Stopped: Just update the interval. */
312	ASMAtomicWriteU64(&pThis->u64NanoInterval, u64NanoInterval);
313	rc = VINF_SUCCESS;
314	}
315	else if (RTThreadSelf() == pThis->hThread)
316	{
317	/* Running: Updating interval from the callback. */
318	uint64_t u64Now = RTTimeNanoTS();
319	pThis->iTick = 0;
320	pThis->u64StartTS = u64Now;
321	pThis->u64NextTS = u64Now;
322	ASMAtomicWriteU64(&pThis->u64NanoInterval, u64NanoInterval);
323	rc = VINF_SUCCESS;
324	}
325	else
326	{
327	/* Running: Stopping */
328	rc = rtTimerLRStop(pThis, true);
329	if (RT_SUCCESS(rc))
330	{
331	ASMAtomicWriteU64(&pThis->u64NanoInterval, u64NanoInterval);
332	rc = rtTimerLRStart(pThis, 0);
333	}
334	}
335
336	return rc;
337	}
338	RT_EXPORT_SYMBOL(RTTimerLRChangeInterval);
339
340
341	static DECLCALLBACK(int) rtTimerLRThread(RTTHREAD hThreadSelf, void *pvUser)
342	{
343	PRTTIMERLRINT pThis = (PRTTIMERLRINT)pvUser;
344	NOREF(hThreadSelf);
345
346	/*
347	* The loop.
348	*/
349	while (!ASMAtomicUoReadBool(&pThis->fDestroyed))
350	{
351	if (ASMAtomicUoReadBool(&pThis->fSuspended))
352	{
353	/* Signal rtTimerLRStop thread. */
354	int rc = RTThreadUserSignal(hThreadSelf);
355	AssertRC(rc);
356
357	ASMAtomicWriteBool(&pThis->fBlocked, true);
358	rc = RTSemEventWait(pThis->hEvent, RT_INDEFINITE_WAIT);
359	if (RT_FAILURE(rc) && rc != VERR_INTERRUPTED)
360	{
361	AssertRC(rc);
362	RTThreadSleep(1000); /* Don't cause trouble! */
363	}
364	ASMAtomicWriteBool(&pThis->fBlocked, false);
365	}
366	else
367	{
368	uint64_t cNanoSeconds;
369	const uint64_t u64NanoTS = RTTimeNanoTS();
370	uint64_t u64NextTS = pThis->u64NextTS;
371	if (u64NanoTS >= u64NextTS)
372	{
373	uint64_t iTick = ++pThis->iTick;
374	pThis->pfnTimer(pThis, pThis->pvUser, iTick);
375
376	/* status changed? */
377	if ( ASMAtomicUoReadBool(&pThis->fSuspended)
378	\|\| ASMAtomicUoReadBool(&pThis->fDestroyed))
379	continue;
380
381	/*
382	* Read timer data (it's all volatile and better if we read it all at once):
383	*/
384	iTick = pThis->iTick;
385	uint64_t const u64StartTS = pThis->u64StartTS;
386	uint64_t const u64NanoInterval = pThis->u64NanoInterval;
387	ASMCompilerBarrier();
388
389	/*
390	* Suspend if one shot.
391	*/
392	if (!u64NanoInterval)
393	{
394	ASMAtomicWriteBool(&pThis->fSuspended, true);
395	continue;
396	}
397
398	/*
399	* Calc the next time we should fire.
400	*
401	* If we're more than 60 intervals behind, just skip ahead. We
402	* don't want the timer thread running wild just because the
403	* clock changed in an unexpected way. As seen in @bugref{3611} this
404	* does happen during suspend/resume, but it may also happen
405	* if we're using a non-monotonic clock as time source.
406	*/
407	u64NextTS = u64StartTS + iTick * u64NanoInterval;
408	if (RT_LIKELY(u64NextTS > u64NanoTS))
409	cNanoSeconds = u64NextTS - u64NanoTS;
410	else
411	{
412	uint64_t iActualTick = (u64NanoTS - u64StartTS) / u64NanoInterval;
413	if (iActualTick - iTick > 60)
414	pThis->iTick = iActualTick - 1;
415	#ifdef IN_RING0
416	cNanoSeconds = RTTimerGetSystemGranularity() / 2;
417	#else
418	cNanoSeconds = RT_NS_1MS;
419	#endif
420	u64NextTS = u64NanoTS + cNanoSeconds;
421	}
422
423	pThis->u64NextTS = u64NextTS;
424	}
425	else
426	cNanoSeconds = u64NextTS - u64NanoTS;
427
428	/* block. */
429	ASMAtomicWriteBool(&pThis->fBlocked, true);
430	int rc = RTSemEventWait(pThis->hEvent,
431	(RTMSINTERVAL)(cNanoSeconds < 1000000 ? 1 : cNanoSeconds / 1000000));
432	if (RT_FAILURE(rc) && rc != VERR_INTERRUPTED && rc != VERR_TIMEOUT)
433	{
434	AssertRC(rc);
435	RTThreadSleep(1000); /* Don't cause trouble! */
436	}
437	ASMAtomicWriteBool(&pThis->fBlocked, false);
438	}
439	}
440
441	/*
442	* Release the timer resources.
443	*/
444	ASMAtomicWriteU32(&pThis->u32Magic, ~RTTIMERLR_MAGIC); /* make the handle invalid. */
445	int rc = RTSemEventDestroy(pThis->hEvent); AssertRC(rc);
446	pThis->hEvent = NIL_RTSEMEVENT;
447	pThis->hThread = NIL_RTTHREAD;
448	RTMemFree(pThis);
449
450	return VINF_SUCCESS;
451	}
452

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source: vbox/trunk/src/VBox/Runtime/generic/timerlr-generic.cpp@ 96407

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