sched-posix.cpp@ 31820

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1	/* $Id: sched-posix.cpp 28800 2010-04-27 08:22:32Z vboxsync $ */
2	/** @file
3	* IPRT - Scheduling, POSIX.
4	*/
5
6	/*
7	* Copyright (C) 2006-2007 Oracle Corporation
8	*
9	* This file is part of VirtualBox Open Source Edition (OSE), as
10	* available from http://www.virtualbox.org. This file is free software;
11	* you can redistribute it and/or modify it under the terms of the GNU
12	* General Public License (GPL) as published by the Free Software
13	* Foundation, in version 2 as it comes in the "COPYING" file of the
14	* VirtualBox OSE distribution. VirtualBox OSE is distributed in the
15	* hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
16	*
17	* The contents of this file may alternatively be used under the terms
18	* of the Common Development and Distribution License Version 1.0
19	* (CDDL) only, as it comes in the "COPYING.CDDL" file of the
20	* VirtualBox OSE distribution, in which case the provisions of the
21	* CDDL are applicable instead of those of the GPL.
22	*
23	* You may elect to license modified versions of this file under the
24	* terms and conditions of either the GPL or the CDDL or both.
25	*/
26
27	/*
28	* !WARNING!
29	*
30	* When talking about lowering and raising priority, we do NOT refer to
31	* the common direction priority values takes on unix systems (lower means
32	* higher). So, when we raise the priority of a linux thread the nice
33	* value will decrease, and when we lower the priority the nice value
34	* will increase. Confusing, right?
35	*
36	* !WARNING!
37	*/
38
39
40
41	/** @def THREAD_LOGGING
42	* Be very careful with enabling this, it may cause deadlocks when combined
43	* with the 'thread' logging prefix.
44	*/
45	#ifdef DOXYGEN_RUNNING
46	#define THREAD_LOGGING
47	#endif
48
49	/*******************************************************************************
50	* Header Files *
51	*******************************************************************************/
52	#define LOG_GROUP RTLOGGROUP_THREAD
53	#include <errno.h>
54	#include <pthread.h>
55	#include <sched.h>
56	#include <unistd.h>
57	#include <sys/resource.h>
58
59	#include <iprt/thread.h>
60	#include <iprt/process.h>
61	#include <iprt/semaphore.h>
62	#include <iprt/string.h>
63	#include <iprt/assert.h>
64	#include <iprt/log.h>
65	#include <iprt/err.h>
66	#include "internal/sched.h"
67	#include "internal/thread.h"
68
69
70	/*******************************************************************************
71	* Structures and Typedefs *
72	*******************************************************************************/
73
74	/** Array scheduler attributes corresponding to each of the thread types. */
75	typedef struct PROCPRIORITYTYPE
76	{
77	/** For sanity include the array index. */
78	RTTHREADTYPE enmType;
79	/** The thread priority or nice delta - depends on which priority type. */
80	int iPriority;
81	} PROCPRIORITYTYPE;
82
83
84	/**
85	* Configuration of one priority.
86	*/
87	typedef struct
88	{
89	/** The priority. */
90	RTPROCPRIORITY enmPriority;
91	/** The name of this priority. */
92	const char *pszName;
93	/** The process nice value. */
94	int iNice;
95	/** The delta applied to the iPriority value. */
96	int iDelta;
97	/** Array scheduler attributes corresponding to each of the thread types. */
98	const PROCPRIORITYTYPE *paTypes;
99	} PROCPRIORITY;
100
101
102	/**
103	* Saved priority settings
104	*/
105	typedef struct
106	{
107	/** Process priority. */
108	int iPriority;
109	/** Process level. */
110	struct sched_param SchedParam;
111	/** Process level. */
112	int iPolicy;
113	/** pthread level. */
114	struct sched_param PthreadSchedParam;
115	/** pthread level. */
116	int iPthreadPolicy;
117	} SAVEDPRIORITY, *PSAVEDPRIORITY;
118
119
120	/*******************************************************************************
121	* Global Variables *
122	*******************************************************************************/
123	/**
124	* Thread level priorities based on a 0..31 priority range
125	* as specified as the minium for SCHED_RR/FIFO. FreeBSD
126	* seems to be using this (needs more research to be
127	* certain).
128	*/
129	static const PROCPRIORITYTYPE g_aTypesThread[RTTHREADTYPE_END] =
130	{
131	{ RTTHREADTYPE_INVALID, -999999999 },
132	{ RTTHREADTYPE_INFREQUENT_POLLER, 5 },
133	{ RTTHREADTYPE_MAIN_HEAVY_WORKER, 12 },
134	{ RTTHREADTYPE_EMULATION, 14 },
135	{ RTTHREADTYPE_DEFAULT, 15 },
136	{ RTTHREADTYPE_GUI, 16 },
137	{ RTTHREADTYPE_MAIN_WORKER, 18 },
138	{ RTTHREADTYPE_VRDP_IO, 24 },
139	{ RTTHREADTYPE_DEBUGGER, 28 },
140	{ RTTHREADTYPE_MSG_PUMP, 29 },
141	{ RTTHREADTYPE_IO, 30 },
142	{ RTTHREADTYPE_TIMER, 31 }
143	};
144
145	static const PROCPRIORITYTYPE g_aTypesThreadFlat[RTTHREADTYPE_END] =
146	{
147	{ RTTHREADTYPE_INVALID, ~0 },
148	{ RTTHREADTYPE_INFREQUENT_POLLER, 15 },
149	{ RTTHREADTYPE_MAIN_HEAVY_WORKER, 15 },
150	{ RTTHREADTYPE_EMULATION, 15 },
151	{ RTTHREADTYPE_DEFAULT, 15 },
152	{ RTTHREADTYPE_GUI, 15 },
153	{ RTTHREADTYPE_MAIN_WORKER, 15 },
154	{ RTTHREADTYPE_VRDP_IO, 15 },
155	{ RTTHREADTYPE_DEBUGGER, 15 },
156	{ RTTHREADTYPE_MSG_PUMP, 15 },
157	{ RTTHREADTYPE_IO, 15 },
158	{ RTTHREADTYPE_TIMER, 15 }
159	};
160
161	/**
162	* Process and thread level priority, full access at thread level.
163	*/
164	static const PROCPRIORITY g_aProcessAndThread[] =
165	{
166	{ RTPROCPRIORITY_FLAT, "Flat", 0, 0, g_aTypesThreadFlat },
167	{ RTPROCPRIORITY_LOW, "Low", 9, 0, g_aTypesThread },
168	{ RTPROCPRIORITY_LOW, "Low", 11, 0, g_aTypesThread },
169	{ RTPROCPRIORITY_LOW, "Low", 15, 0, g_aTypesThread },
170	{ RTPROCPRIORITY_LOW, "Low", 17, 0, g_aTypesThread },
171	{ RTPROCPRIORITY_LOW, "Low", 19, 0, g_aTypesThread },
172	{ RTPROCPRIORITY_LOW, "Low", 7, 0, g_aTypesThread },
173	{ RTPROCPRIORITY_LOW, "Low", 5, 0, g_aTypesThread },
174	{ RTPROCPRIORITY_LOW, "Low", 3, 0, g_aTypesThread },
175	{ RTPROCPRIORITY_LOW, "Low", 1, 0, g_aTypesThread },
176	{ RTPROCPRIORITY_NORMAL, "Normal", 0, 0, g_aTypesThread },
177	{ RTPROCPRIORITY_NORMAL, "Normal", 0, 0, g_aTypesThreadFlat },
178	{ RTPROCPRIORITY_HIGH, "High", -9, 0, g_aTypesThread },
179	{ RTPROCPRIORITY_HIGH, "High", -7, 0, g_aTypesThread },
180	{ RTPROCPRIORITY_HIGH, "High", -5, 0, g_aTypesThread },
181	{ RTPROCPRIORITY_HIGH, "High", -3, 0, g_aTypesThread },
182	{ RTPROCPRIORITY_HIGH, "High", -1, 0, g_aTypesThread },
183	{ RTPROCPRIORITY_HIGH, "High", -9, 0, g_aTypesThreadFlat },
184	{ RTPROCPRIORITY_HIGH, "High", -1, 0, g_aTypesThreadFlat }
185	};
186
187	/**
188	* Deltas for a process in which we are not restricted
189	* to only be lowering the priority.
190	*/
191	static const PROCPRIORITYTYPE g_aTypesUnixFree[RTTHREADTYPE_END] =
192	{
193	{ RTTHREADTYPE_INVALID, -999999999 },
194	{ RTTHREADTYPE_INFREQUENT_POLLER, +3 },
195	{ RTTHREADTYPE_MAIN_HEAVY_WORKER, +2 },
196	{ RTTHREADTYPE_EMULATION, +1 },
197	{ RTTHREADTYPE_DEFAULT, 0 },
198	{ RTTHREADTYPE_GUI, 0 },
199	{ RTTHREADTYPE_MAIN_WORKER, 0 },
200	{ RTTHREADTYPE_VRDP_IO, -1 },
201	{ RTTHREADTYPE_DEBUGGER, -1 },
202	{ RTTHREADTYPE_MSG_PUMP, -2 },
203	{ RTTHREADTYPE_IO, -3 },
204	{ RTTHREADTYPE_TIMER, -4 }
205	};
206
207	/**
208	* Deltas for a process in which we are restricted
209	* to only be lowering the priority.
210	*/
211	static const PROCPRIORITYTYPE g_aTypesUnixRestricted[RTTHREADTYPE_END] =
212	{
213	{ RTTHREADTYPE_INVALID, -999999999 },
214	{ RTTHREADTYPE_INFREQUENT_POLLER, +3 },
215	{ RTTHREADTYPE_MAIN_HEAVY_WORKER, +2 },
216	{ RTTHREADTYPE_EMULATION, +1 },
217	{ RTTHREADTYPE_DEFAULT, 0 },
218	{ RTTHREADTYPE_GUI, 0 },
219	{ RTTHREADTYPE_MAIN_WORKER, 0 },
220	{ RTTHREADTYPE_VRDP_IO, 0 },
221	{ RTTHREADTYPE_DEBUGGER, 0 },
222	{ RTTHREADTYPE_MSG_PUMP, 0 },
223	{ RTTHREADTYPE_IO, 0 },
224	{ RTTHREADTYPE_TIMER, 0 }
225	};
226
227	/**
228	* Deltas for a process in which we are restricted
229	* to only be lowering the priority.
230	*/
231	static const PROCPRIORITYTYPE g_aTypesUnixFlat[RTTHREADTYPE_END] =
232	{
233	{ RTTHREADTYPE_INVALID, -999999999 },
234	{ RTTHREADTYPE_INFREQUENT_POLLER, 0 },
235	{ RTTHREADTYPE_MAIN_HEAVY_WORKER, 0 },
236	{ RTTHREADTYPE_EMULATION, 0 },
237	{ RTTHREADTYPE_DEFAULT, 0 },
238	{ RTTHREADTYPE_GUI, 0 },
239	{ RTTHREADTYPE_MAIN_WORKER, 0 },
240	{ RTTHREADTYPE_VRDP_IO, 0 },
241	{ RTTHREADTYPE_DEBUGGER, 0 },
242	{ RTTHREADTYPE_MSG_PUMP, 0 },
243	{ RTTHREADTYPE_IO, 0 },
244	{ RTTHREADTYPE_TIMER, 0 }
245	};
246
247	/**
248	* Process and thread level priority, full access at thread level.
249	*/
250	static const PROCPRIORITY g_aUnixConfigs[] =
251	{
252	{ RTPROCPRIORITY_FLAT, "Flat", 0, 0, g_aTypesUnixFlat },
253	{ RTPROCPRIORITY_LOW, "Low", 9, 9, g_aTypesUnixFree },
254	{ RTPROCPRIORITY_LOW, "Low", 9, 9, g_aTypesUnixFlat },
255	{ RTPROCPRIORITY_LOW, "Low", 15, 15, g_aTypesUnixFree },
256	{ RTPROCPRIORITY_LOW, "Low", 15, 15, g_aTypesUnixFlat },
257	{ RTPROCPRIORITY_LOW, "Low", 17, 17, g_aTypesUnixFree },
258	{ RTPROCPRIORITY_LOW, "Low", 17, 17, g_aTypesUnixFlat },
259	{ RTPROCPRIORITY_LOW, "Low", 19, 19, g_aTypesUnixFlat },
260	{ RTPROCPRIORITY_LOW, "Low", 9, 9, g_aTypesUnixRestricted },
261	{ RTPROCPRIORITY_LOW, "Low", 15, 15, g_aTypesUnixRestricted },
262	{ RTPROCPRIORITY_LOW, "Low", 17, 17, g_aTypesUnixRestricted },
263	{ RTPROCPRIORITY_NORMAL, "Normal", 0, 0, g_aTypesUnixFree },
264	{ RTPROCPRIORITY_NORMAL, "Normal", 0, 0, g_aTypesUnixRestricted },
265	{ RTPROCPRIORITY_NORMAL, "Normal", 0, 0, g_aTypesUnixFlat },
266	{ RTPROCPRIORITY_HIGH, "High", -9, -9, g_aTypesUnixFree },
267	{ RTPROCPRIORITY_HIGH, "High", -7, -7, g_aTypesUnixFree },
268	{ RTPROCPRIORITY_HIGH, "High", -5, -5, g_aTypesUnixFree },
269	{ RTPROCPRIORITY_HIGH, "High", -3, -3, g_aTypesUnixFree },
270	{ RTPROCPRIORITY_HIGH, "High", -1, -1, g_aTypesUnixFree },
271	{ RTPROCPRIORITY_HIGH, "High", -9, -9, g_aTypesUnixRestricted },
272	{ RTPROCPRIORITY_HIGH, "High", -7, -7, g_aTypesUnixRestricted },
273	{ RTPROCPRIORITY_HIGH, "High", -5, -5, g_aTypesUnixRestricted },
274	{ RTPROCPRIORITY_HIGH, "High", -3, -3, g_aTypesUnixRestricted },
275	{ RTPROCPRIORITY_HIGH, "High", -1, -1, g_aTypesUnixRestricted },
276	{ RTPROCPRIORITY_HIGH, "High", -9, -9, g_aTypesUnixFlat },
277	{ RTPROCPRIORITY_HIGH, "High", -7, -7, g_aTypesUnixFlat },
278	{ RTPROCPRIORITY_HIGH, "High", -5, -5, g_aTypesUnixFlat },
279	{ RTPROCPRIORITY_HIGH, "High", -3, -3, g_aTypesUnixFlat },
280	{ RTPROCPRIORITY_HIGH, "High", -1, -1, g_aTypesUnixFlat }
281	};
282
283	/**
284	* The dynamic default priority configuration.
285	*
286	* This will be recalulated at runtime depending on what the
287	* system allow us to do and what the current priority is.
288	*/
289	static PROCPRIORITY g_aDefaultPriority =
290	{
291	RTPROCPRIORITY_LOW, "Default", 0, 0, g_aTypesUnixRestricted
292	};
293
294	/** Pointer to the current priority configuration. */
295	static const PROCPRIORITY *g_pProcessPriority = &g_aDefaultPriority;
296
297
298	/** Set to what kind of scheduling priority support the host
299	* OS seems to be offering. Determined at runtime.
300	*/
301	static enum
302	{
303	OSPRIOSUP_UNDETERMINED = 0,
304	/** An excellent combination of process and thread level
305	* I.e. setpriority() works on process level, one have to be supervisor
306	* to raise priority as is the custom in unix. While pthread_setschedparam()
307	* works on thread level and we can raise the priority just like we want.
308	*
309	* I think this is what FreeBSD offers. (It is certainly analogous to what
310	* NT offers if you wondered.) Linux on the other hand doesn't provide this
311	* for processes with SCHED_OTHER policy, and I'm not sure if we want to
312	* play around with using the real-time SCHED_RR and SCHED_FIFO which would
313	* require special privilegdes anyway.
314	*/
315	OSPRIOSUP_PROCESS_AND_THREAD_LEVEL,
316	/** A rough thread level priority only.
317	* setpriority() is the only real game in town, and it works on thread level.
318	*/
319	OSPRIOSUP_THREAD_LEVEL
320	} volatile g_enmOsPrioSup = OSPRIOSUP_UNDETERMINED;
321
322	/** Set if we figure we have nice capability, meaning we can use setpriority
323	* to raise the priority. */
324	bool g_fCanNice = false;
325
326
327	/*******************************************************************************
328	* Internal Functions *
329	*******************************************************************************/
330
331
332	/**
333	* Saves all the scheduling attributes we can think of.
334	*/
335	static void rtSchedNativeSave(PSAVEDPRIORITY pSave)
336	{
337	memset(pSave, 0xff, sizeof(*pSave));
338
339	errno = 0;
340	pSave->iPriority = getpriority(PRIO_PROCESS, 0 /* current process */);
341	Assert(errno == 0);
342
343	errno = 0;
344	sched_getparam(0 /* current process */, &pSave->SchedParam);
345	Assert(errno == 0);
346
347	errno = 0;
348	pSave->iPolicy = sched_getscheduler(0 /* current process */);
349	Assert(errno == 0);
350
351	int rc = pthread_getschedparam(pthread_self(), &pSave->iPthreadPolicy, &pSave->PthreadSchedParam);
352	Assert(rc == 0); NOREF(rc);
353	}
354
355
356	/**
357	* Restores scheduling attributes.
358	* Most of this won't work right, but anyway...
359	*/
360	static void rtSchedNativeRestore(PSAVEDPRIORITY pSave)
361	{
362	setpriority(PRIO_PROCESS, 0, pSave->iPriority);
363	sched_setscheduler(0, pSave->iPolicy, &pSave->SchedParam);
364	sched_setparam(0, &pSave->SchedParam);
365	pthread_setschedparam(pthread_self(), pSave->iPthreadPolicy, &pSave->PthreadSchedParam);
366	}
367
368
369	/**
370	* Starts a worker thread and wait for it to complete.
371	* We cannot use RTThreadCreate since we're already owner of the RW lock.
372	*/
373	static int rtSchedCreateThread(void (pfnThread)(void pvArg), void pvArg)
374	{
375	/*
376	* Setup thread attributes.
377	*/
378	pthread_attr_t ThreadAttr;
379	int rc = pthread_attr_init(&ThreadAttr);
380	if (!rc)
381	{
382	rc = pthread_attr_setdetachstate(&ThreadAttr, PTHREAD_CREATE_JOINABLE);
383	if (!rc)
384	{
385	rc = pthread_attr_setstacksize(&ThreadAttr, 128*1024);
386	if (!rc)
387	{
388	/*
389	* Create the thread.
390	*/
391	pthread_t Thread;
392	rc = pthread_create(&Thread, &ThreadAttr, pfnThread, pvArg);
393	if (!rc)
394	{
395	/*
396	* Wait for the thread to finish.
397	*/
398	void pvRet = (void )-1;
399	do
400	{
401	rc = pthread_join(Thread, &pvRet);
402	} while (errno == EINTR);
403	if (rc)
404	return RTErrConvertFromErrno(rc);
405	return (int)(uintptr_t)pvRet;
406	}
407	}
408	}
409	pthread_attr_destroy(&ThreadAttr);
410	}
411	return RTErrConvertFromErrno(rc);
412	}
413
414
415	static void rtSchedDumpPriority(void)
416	{
417	#ifdef THREAD_LOGGING
418	Log(("Priority: g_fCanNice=%d g_enmOsPrioSup=%d\n", g_fCanNice, g_enmOsPrioSup));
419	Log(("Priority: enmPriority=%d \"%s\" iNice=%d iDelta=%d\n",
420	g_pProcessPriority->enmPriority,
421	g_pProcessPriority->pszName,
422	g_pProcessPriority->iNice,
423	g_pProcessPriority->iDelta));
424	Log(("Priority: %2d INFREQUENT_POLLER = %d\n", RTTHREADTYPE_INFREQUENT_POLLER, g_pProcessPriority->paTypes[RTTHREADTYPE_INFREQUENT_POLLER].iPriority));
425	Log(("Priority: %2d MAIN_HEAVY_WORKER = %d\n", RTTHREADTYPE_MAIN_HEAVY_WORKER, g_pProcessPriority->paTypes[RTTHREADTYPE_MAIN_HEAVY_WORKER].iPriority));
426	Log(("Priority: %2d EMULATION = %d\n", RTTHREADTYPE_EMULATION , g_pProcessPriority->paTypes[RTTHREADTYPE_EMULATION ].iPriority));
427	Log(("Priority: %2d DEFAULT = %d\n", RTTHREADTYPE_DEFAULT , g_pProcessPriority->paTypes[RTTHREADTYPE_DEFAULT ].iPriority));
428	Log(("Priority: %2d GUI = %d\n", RTTHREADTYPE_GUI , g_pProcessPriority->paTypes[RTTHREADTYPE_GUI ].iPriority));
429	Log(("Priority: %2d MAIN_WORKER = %d\n", RTTHREADTYPE_MAIN_WORKER , g_pProcessPriority->paTypes[RTTHREADTYPE_MAIN_WORKER ].iPriority));
430	Log(("Priority: %2d VRDP_IO = %d\n", RTTHREADTYPE_VRDP_IO , g_pProcessPriority->paTypes[RTTHREADTYPE_VRDP_IO ].iPriority));
431	Log(("Priority: %2d DEBUGGER = %d\n", RTTHREADTYPE_DEBUGGER , g_pProcessPriority->paTypes[RTTHREADTYPE_DEBUGGER ].iPriority));
432	Log(("Priority: %2d MSG_PUMP = %d\n", RTTHREADTYPE_MSG_PUMP , g_pProcessPriority->paTypes[RTTHREADTYPE_MSG_PUMP ].iPriority));
433	Log(("Priority: %2d IO = %d\n", RTTHREADTYPE_IO , g_pProcessPriority->paTypes[RTTHREADTYPE_IO ].iPriority));
434	Log(("Priority: %2d TIMER = %d\n", RTTHREADTYPE_TIMER , g_pProcessPriority->paTypes[RTTHREADTYPE_TIMER ].iPriority));
435	#endif
436	}
437
438
439	/**
440	* The prober thread.
441	* We don't want to mess with the priority of the calling thread.
442	*
443	* @remark This is pretty presumptive stuff, but if it works on Linux and
444	* FreeBSD it does what I want.
445	*/
446	static void rtSchedNativeProberThread(void pvUser)
447	{
448	SAVEDPRIORITY SavedPriority;
449	rtSchedNativeSave(&SavedPriority);
450
451	/*
452	* Let's first try and see what we get on a thread level.
453	*/
454	int iMax = sched_get_priority_max(SavedPriority.iPthreadPolicy);
455	int iMin = sched_get_priority_min(SavedPriority.iPthreadPolicy);
456	if (iMax - iMin >= 32)
457	{
458	pthread_t Self = pthread_self();
459	int i = iMin;
460	while (i <= iMax)
461	{
462	struct sched_param SchedParam = SavedPriority.PthreadSchedParam;
463	SchedParam.sched_priority = i;
464	if (pthread_setschedparam(Self, SavedPriority.iPthreadPolicy, &SchedParam))
465	break;
466	i++;
467	}
468	if (i == iMax)
469	g_enmOsPrioSup = OSPRIOSUP_PROCESS_AND_THREAD_LEVEL;
470	}
471
472	/*
473	* Ok, we didn't have the good stuff, so let's fall back on the unix stuff.
474	*/
475	if (g_enmOsPrioSup == OSPRIOSUP_UNDETERMINED)
476	g_enmOsPrioSup = OSPRIOSUP_THREAD_LEVEL;
477
478	/*
479	* Check if we can get higher priority (typically only root can do this).
480	* (Won't work right if our priority is -19 to start with, but what the heck.)
481	*
482	* We assume that the unix priority is -19 to 19. I know there are defines
483	* for this, but I don't remember which and if I'm awake enough to make sense
484	* of them from any SuS spec.
485	*/
486	int iStart = getpriority(PRIO_PROCESS, 0);
487	int i = iStart;
488	while (i-- > -19)
489	{
490	if (setpriority(PRIO_PROCESS, 0, i))
491	break;
492	}
493	if (getpriority(PRIO_PROCESS, 0) != iStart)
494	g_fCanNice = true;
495	else
496	g_fCanNice = false;
497
498	/* done */
499	rtSchedNativeRestore(&SavedPriority);
500	return (void *)VINF_SUCCESS;
501	}
502
503
504	/**
505	* Calculate the scheduling properties for all the threads in the default
506	* process priority, assuming the current thread have the type enmType.
507	*
508	* @returns iprt status code.
509	* @param enmType The thread type to be assumed for the current thread.
510	*/
511	int rtSchedNativeCalcDefaultPriority(RTTHREADTYPE enmType)
512	{
513	Assert(enmType > RTTHREADTYPE_INVALID && enmType < RTTHREADTYPE_END);
514
515	/*
516	* First figure out what's supported by the OS.
517	*/
518	if (g_enmOsPrioSup == OSPRIOSUP_UNDETERMINED)
519	{
520	int iPriority = getpriority(PRIO_PROCESS, 0);
521	int rc = rtSchedCreateThread(rtSchedNativeProberThread, NULL);
522	if (RT_FAILURE(rc))
523	return rc;
524	if (g_enmOsPrioSup == OSPRIOSUP_UNDETERMINED)
525	g_enmOsPrioSup = OSPRIOSUP_THREAD_LEVEL;
526	Assert(getpriority(PRIO_PROCESS, 0) == iPriority); NOREF(iPriority);
527	}
528
529	/*
530	* Now let's see what we can do...
531	*/
532	int iPriority = getpriority(PRIO_PROCESS, 0);
533	switch (g_enmOsPrioSup)
534	{
535	case OSPRIOSUP_PROCESS_AND_THREAD_LEVEL:
536	{
537	g_aDefaultPriority.iNice = iPriority;
538	g_aDefaultPriority.iDelta = 0;
539	g_aDefaultPriority.paTypes = g_aTypesThread;
540	Assert(enmType == g_aDefaultPriority.paTypes[enmType].enmType);
541	break;
542	}
543
544	case OSPRIOSUP_THREAD_LEVEL:
545	{
546	if (g_fCanNice)
547	g_aDefaultPriority.paTypes = g_aTypesUnixFree;
548	else
549	g_aDefaultPriority.paTypes = g_aTypesUnixRestricted;
550	Assert(enmType == g_aDefaultPriority.paTypes[enmType].enmType);
551	g_aDefaultPriority.iNice = iPriority - g_aDefaultPriority.paTypes[enmType].iPriority;
552	g_aDefaultPriority.iDelta = g_aDefaultPriority.iNice;
553	break;
554	}
555
556	default:
557	AssertFailed();
558	break;
559	}
560	rtSchedDumpPriority();
561	return VINF_SUCCESS;
562	}
563
564
565	/**
566	* The validator thread.
567	* We don't want to mess with the priority of the calling thread.
568	*
569	* @remark This is pretty presumptive stuff, but if it works on Linux and
570	* FreeBSD it does what I want.
571	*/
572	static void rtSchedNativeValidatorThread(void pvUser)
573	{
574	const PROCPRIORITY pCfg = (const PROCPRIORITY )pvUser;
575	SAVEDPRIORITY SavedPriority;
576	rtSchedNativeSave(&SavedPriority);
577
578	int rc = VINF_SUCCESS;
579	switch (g_enmOsPrioSup)
580	{
581	/*
582	* Try set the specified process priority and then try
583	* out all the thread priorities which are used.
584	*/
585	case OSPRIOSUP_PROCESS_AND_THREAD_LEVEL:
586	{
587	if (!setpriority(PRIO_PROCESS, 0, pCfg->iNice))
588	{
589	int iMin = sched_get_priority_min(SavedPriority.iPolicy);
590	pthread_t Self = pthread_self();
591	for (int i = RTTHREADTYPE_INVALID + 1; i < RTTHREADTYPE_END; i++)
592	{
593	struct sched_param SchedParam = SavedPriority.PthreadSchedParam;
594	SchedParam.sched_priority = pCfg->paTypes[i].iPriority
595	+ pCfg->iDelta + iMin;
596	rc = pthread_setschedparam(Self, SavedPriority.iPthreadPolicy, &SchedParam);
597	if (rc)
598	{
599	rc = RTErrConvertFromErrno(rc);
600	break;
601	}
602	}
603	}
604	else
605	rc = RTErrConvertFromErrno(errno);
606	break;
607	}
608
609	/*
610	* Try out the priorities from the top and down.
611	*/
612	case OSPRIOSUP_THREAD_LEVEL:
613	{
614	int i = RTTHREADTYPE_END;
615	while (--i > RTTHREADTYPE_INVALID)
616	{
617	int iPriority = pCfg->paTypes[i].iPriority + pCfg->iDelta;
618	if (setpriority(PRIO_PROCESS, 0, iPriority))
619	{
620	rc = RTErrConvertFromErrno(errno);
621	break;
622	}
623	}
624	break;
625	}
626
627	default:
628	AssertFailed();
629	break;
630	}
631
632	/* done */
633	rtSchedNativeRestore(&SavedPriority);
634	return (void *)rc;
635	}
636
637
638	/**
639	* Validates and sets the process priority.
640	* This will check that all rtThreadNativeSetPriority() will success for all the
641	* thread types when applied to the current thread.
642	*
643	* @returns iprt status code.
644	* @param enmPriority The priority to validate and set.
645	*/
646	int rtProcNativeSetPriority(RTPROCPRIORITY enmPriority)
647	{
648	Assert(enmPriority > RTPROCPRIORITY_INVALID && enmPriority < RTPROCPRIORITY_LAST);
649
650	int rc = VINF_SUCCESS;
651	if (enmPriority == RTPROCPRIORITY_DEFAULT)
652	g_pProcessPriority = &g_aDefaultPriority;
653	else
654	{
655	/*
656	* Select the array to search.
657	*/
658	const PROCPRIORITY *pa;
659	unsigned c;
660	switch (g_enmOsPrioSup)
661	{
662	case OSPRIOSUP_PROCESS_AND_THREAD_LEVEL:
663	pa = g_aProcessAndThread;
664	c = RT_ELEMENTS(g_aProcessAndThread);
665	break;
666	case OSPRIOSUP_THREAD_LEVEL:
667	pa = g_aUnixConfigs;
668	c = RT_ELEMENTS(g_aUnixConfigs);
669	break;
670	default:
671	pa = NULL;
672	c = 0;
673	break;
674	}
675
676	/*
677	* Search the array.
678	*/
679	rc = VERR_FILE_NOT_FOUND;
680	unsigned i;
681	for (i = 0; i < c; i++)
682	{
683	if (pa[i].enmPriority == enmPriority)
684	{
685	/*
686	* Validate it.
687	*/
688	int iPriority = getpriority(PRIO_PROCESS, 0);
689	int rc3 = rtSchedCreateThread(rtSchedNativeValidatorThread, (void *)&pa[i]);
690	Assert(getpriority(PRIO_PROCESS, 0) == iPriority); NOREF(iPriority);
691	if (RT_SUCCESS(rc))
692	rc = rc3;
693	if (RT_SUCCESS(rc))
694	break;
695	}
696	}
697
698	/*
699	* Did we get lucky?
700	* If so update process priority and globals.
701	*/
702	if (RT_SUCCESS(rc))
703	{
704	switch (g_enmOsPrioSup)
705	{
706	case OSPRIOSUP_PROCESS_AND_THREAD_LEVEL:
707	if (setpriority(PRIO_PROCESS, 0, pa[i].iNice))
708	{
709	rc = RTErrConvertFromErrno(errno);
710	AssertMsgFailed(("setpriority(,,%d) -> errno=%d rc=%Rrc\n", pa[i].iNice, errno, rc));
711	}
712	break;
713
714	default:
715	break;
716	}
717
718	if (RT_SUCCESS(rc))
719	g_pProcessPriority = &pa[i];
720	}
721	}
722
723	#ifdef THREAD_LOGGING
724	LogFlow(("rtProcNativeSetPriority: returns %Rrc enmPriority=%d\n", rc, enmPriority));
725	rtSchedDumpPriority();
726	#endif
727	return rc;
728	}
729
730
731	/**
732	* Sets the priority of the thread according to the thread type
733	* and current process priority.
734	*
735	* The RTTHREADINT::enmType member has not yet been updated and will be updated by
736	* the caller on a successful return.
737	*
738	* @returns iprt status code.
739	* @param Thread The thread in question.
740	* @param enmType The thread type.
741	*/
742	int rtThreadNativeSetPriority(PRTTHREADINT pThread, RTTHREADTYPE enmType)
743	{
744	Assert(enmType > RTTHREADTYPE_INVALID && enmType < RTTHREADTYPE_END);
745	Assert(enmType == g_pProcessPriority->paTypes[enmType].enmType);
746	Assert((pthread_t)pThread->Core.Key == pthread_self());
747
748	int rc = VINF_SUCCESS;
749	switch (g_enmOsPrioSup)
750	{
751	case OSPRIOSUP_PROCESS_AND_THREAD_LEVEL:
752	{
753	struct sched_param SchedParam = {-9999999};
754	int iPolicy = -7777777;
755	pthread_t Self = pthread_self();
756	rc = pthread_getschedparam(Self, &iPolicy, &SchedParam);
757	if (!rc)
758	{
759	SchedParam.sched_priority = g_pProcessPriority->paTypes[enmType].iPriority
760	+ g_pProcessPriority->iDelta
761	+ sched_get_priority_min(iPolicy);
762	rc = pthread_setschedparam(Self, iPolicy, &SchedParam);
763	if (!rc)
764	{
765	#ifdef THREAD_LOGGING
766	Log(("rtThreadNativeSetPriority: Thread=%p enmType=%d iPolicy=%d sched_priority=%d pid=%d\n",
767	pThread->Core.Key, enmType, iPolicy, SchedParam.sched_priority, getpid()));
768	#endif
769	break;
770	}
771	}
772
773	int rcNative = rc;
774	rc = RTErrConvertFromErrno(rc);
775	AssertMsgFailed(("pthread_[gs]etschedparam(%p, %d, {%d}) -> rcNative=%d rc=%Rrc\n",
776	(void *)Self, iPolicy, SchedParam.sched_priority, rcNative, rc)); NOREF(rcNative);
777	break;
778	}
779
780	case OSPRIOSUP_THREAD_LEVEL:
781	{
782	int iPriority = g_pProcessPriority->paTypes[enmType].iPriority + g_pProcessPriority->iDelta;
783	if (!setpriority(PRIO_PROCESS, 0, iPriority))
784	{
785	AssertMsg(iPriority == getpriority(PRIO_PROCESS, 0), ("iPriority=%d getpriority()=%d\n", iPriority, getpriority(PRIO_PROCESS, 0)));
786	#ifdef THREAD_LOGGING
787	Log(("rtThreadNativeSetPriority: Thread=%p enmType=%d iPriority=%d pid=%d\n", pThread->Core.Key, enmType, iPriority, getpid()));
788	#endif
789	}
790	else
791	{
792	#if 0
793	rc = RTErrConvertFromErrno(errno);
794	AssertMsgFailed(("setpriority(,, %d) -> errno=%d rc=%Rrc\n", iPriority, errno, rc));
795	#else
796	/** @todo
797	* Just keep quiet about failures now - we'll fail here because we're not
798	* allowed to raise our own priority. This is a problem when starting the
799	* threads with higher priority from EMT (i.e. most threads it starts).
800	* This is apparently inherited from the parent in some cases and not
801	* in other cases. I guess this would come down to which kind of pthread
802	* implementation is actually in use, and how many sensible patches which
803	* are installed.
804	* I need to find a system where this problem shows up in order to come up
805	* with a proper fix. There's an pthread_create attribute for not inherting
806	* scheduler stuff I think...
807	*/
808	rc = VINF_SUCCESS;
809	#endif
810	}
811	break;
812	}
813
814	/*
815	* Any thread created before we determin the default config, remains unchanged!
816	* The prober thread above is one of those.
817	*/
818	default:
819	break;
820	}
821
822	return rc;
823	}
824

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source: vbox/trunk/src/VBox/Runtime/r3/posix/sched-posix.cpp@ 31820

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