sched-posix.cpp@ 82660

Last change on this file since 82660 was 77910, checked in by vboxsync, 6 years ago
Main: bugref:7929: Added ability to change the priority of the VM process
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File size: 31.7 KB

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1	/* $Id: sched-posix.cpp 77910 2019-03-27 11:33:01Z vboxsync $ */
2	/** @file
3	* IPRT - Scheduling, POSIX.
4	*/
5
6	/*
7	* Copyright (C) 2006-2019 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	/*********************************************************************************************************************************
51	* Header Files *
52	*********************************************************************************************************************************/
53	#define LOG_GROUP RTLOGGROUP_THREAD
54	#include <errno.h>
55	#include <pthread.h>
56	#include <sched.h>
57	#include <unistd.h>
58	#include <sys/resource.h>
59
60	#include <iprt/thread.h>
61	#include <iprt/process.h>
62	#include <iprt/semaphore.h>
63	#include <iprt/string.h>
64	#include <iprt/assert.h>
65	#include <iprt/log.h>
66	#include <iprt/err.h>
67	#include "internal/sched.h"
68	#include "internal/thread.h"
69
70
71	/*********************************************************************************************************************************
72	* Structures and Typedefs *
73	*********************************************************************************************************************************/
74
75	/** Array scheduler attributes corresponding to each of the thread types. */
76	typedef struct PROCPRIORITYTYPE
77	{
78	/** For sanity include the array index. */
79	RTTHREADTYPE enmType;
80	/** The thread priority or nice delta - depends on which priority type. */
81	int iPriority;
82	} PROCPRIORITYTYPE;
83
84
85	/**
86	* Configuration of one priority.
87	*/
88	typedef struct
89	{
90	/** The priority. */
91	RTPROCPRIORITY enmPriority;
92	/** The name of this priority. */
93	const char *pszName;
94	/** The process nice value. */
95	int iNice;
96	/** The delta applied to the iPriority value. */
97	int iDelta;
98	/** Array scheduler attributes corresponding to each of the thread types. */
99	const PROCPRIORITYTYPE *paTypes;
100	} PROCPRIORITY;
101
102
103	/**
104	* Saved priority settings
105	*/
106	typedef struct
107	{
108	/** Process priority. */
109	int iPriority;
110	/** Process level. */
111	struct sched_param SchedParam;
112	/** Process level. */
113	int iPolicy;
114	/** pthread level. */
115	struct sched_param PthreadSchedParam;
116	/** pthread level. */
117	int iPthreadPolicy;
118	} SAVEDPRIORITY, *PSAVEDPRIORITY;
119
120
121	/*********************************************************************************************************************************
122	* Global Variables *
123	*********************************************************************************************************************************/
124	/**
125	* Thread level priorities based on a 0..31 priority range
126	* as specified as the minimum for SCHED_RR/FIFO. FreeBSD
127	* seems to be using this (needs more research to be
128	* certain).
129	*/
130	static const PROCPRIORITYTYPE g_aTypesThread[RTTHREADTYPE_END] =
131	{
132	{ RTTHREADTYPE_INVALID, -999999999 },
133	{ RTTHREADTYPE_INFREQUENT_POLLER, 5 },
134	{ RTTHREADTYPE_MAIN_HEAVY_WORKER, 12 },
135	{ RTTHREADTYPE_EMULATION, 14 },
136	{ RTTHREADTYPE_DEFAULT, 15 },
137	{ RTTHREADTYPE_GUI, 16 },
138	{ RTTHREADTYPE_MAIN_WORKER, 18 },
139	{ RTTHREADTYPE_VRDP_IO, 24 },
140	{ RTTHREADTYPE_DEBUGGER, 28 },
141	{ RTTHREADTYPE_MSG_PUMP, 29 },
142	{ RTTHREADTYPE_IO, 30 },
143	{ RTTHREADTYPE_TIMER, 31 }
144	};
145
146	static const PROCPRIORITYTYPE g_aTypesThreadFlat[RTTHREADTYPE_END] =
147	{
148	{ RTTHREADTYPE_INVALID, ~0 },
149	{ RTTHREADTYPE_INFREQUENT_POLLER, 15 },
150	{ RTTHREADTYPE_MAIN_HEAVY_WORKER, 15 },
151	{ RTTHREADTYPE_EMULATION, 15 },
152	{ RTTHREADTYPE_DEFAULT, 15 },
153	{ RTTHREADTYPE_GUI, 15 },
154	{ RTTHREADTYPE_MAIN_WORKER, 15 },
155	{ RTTHREADTYPE_VRDP_IO, 15 },
156	{ RTTHREADTYPE_DEBUGGER, 15 },
157	{ RTTHREADTYPE_MSG_PUMP, 15 },
158	{ RTTHREADTYPE_IO, 15 },
159	{ RTTHREADTYPE_TIMER, 15 }
160	};
161
162	/**
163	* Process and thread level priority, full access at thread level.
164	*/
165	static const PROCPRIORITY g_aProcessAndThread[] =
166	{
167	{ RTPROCPRIORITY_FLAT, "Flat", 0, 0, g_aTypesThreadFlat },
168	{ RTPROCPRIORITY_LOW, "Low", 9, 0, g_aTypesThread },
169	{ RTPROCPRIORITY_LOW, "Low", 11, 0, g_aTypesThread },
170	{ RTPROCPRIORITY_LOW, "Low", 15, 0, g_aTypesThread },
171	{ RTPROCPRIORITY_LOW, "Low", 17, 0, g_aTypesThread },
172	{ RTPROCPRIORITY_LOW, "Low", 19, 0, g_aTypesThread },
173	{ RTPROCPRIORITY_LOW, "Low", 7, 0, g_aTypesThread },
174	{ RTPROCPRIORITY_LOW, "Low", 5, 0, g_aTypesThread },
175	{ RTPROCPRIORITY_LOW, "Low", 3, 0, g_aTypesThread },
176	{ RTPROCPRIORITY_LOW, "Low", 1, 0, g_aTypesThread },
177	{ RTPROCPRIORITY_NORMAL, "Normal", 0, 0, g_aTypesThread },
178	{ RTPROCPRIORITY_NORMAL, "Normal", 0, 0, g_aTypesThreadFlat },
179	{ RTPROCPRIORITY_HIGH, "High", -9, 0, g_aTypesThread },
180	{ RTPROCPRIORITY_HIGH, "High", -7, 0, g_aTypesThread },
181	{ RTPROCPRIORITY_HIGH, "High", -5, 0, g_aTypesThread },
182	{ RTPROCPRIORITY_HIGH, "High", -3, 0, g_aTypesThread },
183	{ RTPROCPRIORITY_HIGH, "High", -1, 0, g_aTypesThread },
184	{ RTPROCPRIORITY_HIGH, "High", -9, 0, g_aTypesThreadFlat },
185	{ RTPROCPRIORITY_HIGH, "High", -1, 0, g_aTypesThreadFlat }
186	};
187
188	/**
189	* Deltas for a process in which we are not restricted
190	* to only be lowering the priority.
191	*/
192	static const PROCPRIORITYTYPE g_aTypesUnixFree[RTTHREADTYPE_END] =
193	{
194	{ RTTHREADTYPE_INVALID, -999999999 },
195	{ RTTHREADTYPE_INFREQUENT_POLLER, +3 },
196	{ RTTHREADTYPE_MAIN_HEAVY_WORKER, +2 },
197	{ RTTHREADTYPE_EMULATION, +1 },
198	{ RTTHREADTYPE_DEFAULT, 0 },
199	{ RTTHREADTYPE_GUI, 0 },
200	{ RTTHREADTYPE_MAIN_WORKER, 0 },
201	{ RTTHREADTYPE_VRDP_IO, -1 },
202	{ RTTHREADTYPE_DEBUGGER, -1 },
203	{ RTTHREADTYPE_MSG_PUMP, -2 },
204	{ RTTHREADTYPE_IO, -3 },
205	{ RTTHREADTYPE_TIMER, -4 }
206	};
207
208	/**
209	* Deltas for a process in which we are restricted
210	* to only be lowering the priority.
211	*/
212	static const PROCPRIORITYTYPE g_aTypesUnixRestricted[RTTHREADTYPE_END] =
213	{
214	{ RTTHREADTYPE_INVALID, -999999999 },
215	{ RTTHREADTYPE_INFREQUENT_POLLER, +3 },
216	{ RTTHREADTYPE_MAIN_HEAVY_WORKER, +2 },
217	{ RTTHREADTYPE_EMULATION, +1 },
218	{ RTTHREADTYPE_DEFAULT, 0 },
219	{ RTTHREADTYPE_GUI, 0 },
220	{ RTTHREADTYPE_MAIN_WORKER, 0 },
221	{ RTTHREADTYPE_VRDP_IO, 0 },
222	{ RTTHREADTYPE_DEBUGGER, 0 },
223	{ RTTHREADTYPE_MSG_PUMP, 0 },
224	{ RTTHREADTYPE_IO, 0 },
225	{ RTTHREADTYPE_TIMER, 0 }
226	};
227
228	/**
229	* Deltas for a process in which we are restricted
230	* to only be lowering the priority.
231	*/
232	static const PROCPRIORITYTYPE g_aTypesUnixFlat[RTTHREADTYPE_END] =
233	{
234	{ RTTHREADTYPE_INVALID, -999999999 },
235	{ RTTHREADTYPE_INFREQUENT_POLLER, 0 },
236	{ RTTHREADTYPE_MAIN_HEAVY_WORKER, 0 },
237	{ RTTHREADTYPE_EMULATION, 0 },
238	{ RTTHREADTYPE_DEFAULT, 0 },
239	{ RTTHREADTYPE_GUI, 0 },
240	{ RTTHREADTYPE_MAIN_WORKER, 0 },
241	{ RTTHREADTYPE_VRDP_IO, 0 },
242	{ RTTHREADTYPE_DEBUGGER, 0 },
243	{ RTTHREADTYPE_MSG_PUMP, 0 },
244	{ RTTHREADTYPE_IO, 0 },
245	{ RTTHREADTYPE_TIMER, 0 }
246	};
247
248	/**
249	* Process and thread level priority, full access at thread level.
250	*/
251	static const PROCPRIORITY g_aUnixConfigs[] =
252	{
253	{ RTPROCPRIORITY_FLAT, "Flat", 0, 0, g_aTypesUnixFlat },
254	{ RTPROCPRIORITY_LOW, "Low", 9, 9, g_aTypesUnixFree },
255	{ RTPROCPRIORITY_LOW, "Low", 9, 9, g_aTypesUnixFlat },
256	{ RTPROCPRIORITY_LOW, "Low", 15, 15, g_aTypesUnixFree },
257	{ RTPROCPRIORITY_LOW, "Low", 15, 15, g_aTypesUnixFlat },
258	{ RTPROCPRIORITY_LOW, "Low", 17, 17, g_aTypesUnixFree },
259	{ RTPROCPRIORITY_LOW, "Low", 17, 17, g_aTypesUnixFlat },
260	{ RTPROCPRIORITY_LOW, "Low", 19, 19, g_aTypesUnixFlat },
261	{ RTPROCPRIORITY_LOW, "Low", 9, 9, g_aTypesUnixRestricted },
262	{ RTPROCPRIORITY_LOW, "Low", 15, 15, g_aTypesUnixRestricted },
263	{ RTPROCPRIORITY_LOW, "Low", 17, 17, g_aTypesUnixRestricted },
264	{ RTPROCPRIORITY_NORMAL, "Normal", 0, 0, g_aTypesUnixFree },
265	{ RTPROCPRIORITY_NORMAL, "Normal", 0, 0, g_aTypesUnixRestricted },
266	{ RTPROCPRIORITY_NORMAL, "Normal", 0, 0, g_aTypesUnixFlat },
267	{ RTPROCPRIORITY_HIGH, "High", -9, -9, g_aTypesUnixFree },
268	{ RTPROCPRIORITY_HIGH, "High", -7, -7, g_aTypesUnixFree },
269	{ RTPROCPRIORITY_HIGH, "High", -5, -5, g_aTypesUnixFree },
270	{ RTPROCPRIORITY_HIGH, "High", -3, -3, g_aTypesUnixFree },
271	{ RTPROCPRIORITY_HIGH, "High", -1, -1, g_aTypesUnixFree },
272	{ RTPROCPRIORITY_HIGH, "High", -9, -9, g_aTypesUnixRestricted },
273	{ RTPROCPRIORITY_HIGH, "High", -7, -7, g_aTypesUnixRestricted },
274	{ RTPROCPRIORITY_HIGH, "High", -5, -5, g_aTypesUnixRestricted },
275	{ RTPROCPRIORITY_HIGH, "High", -3, -3, g_aTypesUnixRestricted },
276	{ RTPROCPRIORITY_HIGH, "High", -1, -1, g_aTypesUnixRestricted },
277	{ RTPROCPRIORITY_HIGH, "High", -9, -9, g_aTypesUnixFlat },
278	{ RTPROCPRIORITY_HIGH, "High", -7, -7, g_aTypesUnixFlat },
279	{ RTPROCPRIORITY_HIGH, "High", -5, -5, g_aTypesUnixFlat },
280	{ RTPROCPRIORITY_HIGH, "High", -3, -3, g_aTypesUnixFlat },
281	{ RTPROCPRIORITY_HIGH, "High", -1, -1, g_aTypesUnixFlat }
282	};
283
284	/**
285	* The dynamic default priority configuration.
286	*
287	* This will be recalulated at runtime depending on what the
288	* system allow us to do and what the current priority is.
289	*/
290	static PROCPRIORITY g_aDefaultPriority =
291	{
292	RTPROCPRIORITY_LOW, "Default", 0, 0, g_aTypesUnixRestricted
293	};
294
295	/** Pointer to the current priority configuration. */
296	static const PROCPRIORITY *g_pProcessPriority = &g_aDefaultPriority;
297
298
299	/** Set to what kind of scheduling priority support the host
300	* OS seems to be offering. Determined at runtime.
301	*/
302	static enum
303	{
304	OSPRIOSUP_UNDETERMINED = 0,
305	/** An excellent combination of process and thread level
306	* I.e. setpriority() works on process level, one have to be supervisor
307	* to raise priority as is the custom in unix. While pthread_setschedparam()
308	* works on thread level and we can raise the priority just like we want.
309	*
310	* I think this is what FreeBSD offers. (It is certainly analogous to what
311	* NT offers if you wondered.) Linux on the other hand doesn't provide this
312	* for processes with SCHED_OTHER policy, and I'm not sure if we want to
313	* play around with using the real-time SCHED_RR and SCHED_FIFO which would
314	* require special privileges anyway.
315	*/
316	OSPRIOSUP_PROCESS_AND_THREAD_LEVEL,
317	/** A rough thread level priority only.
318	* setpriority() is the only real game in town, and it works on thread level.
319	*/
320	OSPRIOSUP_THREAD_LEVEL
321	} volatile g_enmOsPrioSup = OSPRIOSUP_UNDETERMINED;
322
323	/** Set if we figure we have nice capability, meaning we can use setpriority
324	* to raise the priority. */
325	static bool g_fCanNice = false;
326
327
328	/*********************************************************************************************************************************
329	* Internal Functions *
330	*********************************************************************************************************************************/
331
332
333	/**
334	* Saves all the scheduling attributes we can think of.
335	*/
336	static void rtSchedNativeSave(PSAVEDPRIORITY pSave)
337	{
338	memset(pSave, 0xff, sizeof(*pSave));
339
340	errno = 0;
341	pSave->iPriority = getpriority(PRIO_PROCESS, 0 /* current process */);
342	Assert(errno == 0);
343
344	errno = 0;
345	sched_getparam(0 /* current process */, &pSave->SchedParam);
346	Assert(errno == 0);
347
348	errno = 0;
349	pSave->iPolicy = sched_getscheduler(0 /* current process */);
350	Assert(errno == 0);
351
352	int rc = pthread_getschedparam(pthread_self(), &pSave->iPthreadPolicy, &pSave->PthreadSchedParam);
353	Assert(rc == 0); NOREF(rc);
354	}
355
356
357	/**
358	* Restores scheduling attributes.
359	* Most of this won't work right, but anyway...
360	*/
361	static void rtSchedNativeRestore(PSAVEDPRIORITY pSave)
362	{
363	setpriority(PRIO_PROCESS, 0, pSave->iPriority);
364	sched_setscheduler(0, pSave->iPolicy, &pSave->SchedParam);
365	sched_setparam(0, &pSave->SchedParam);
366	pthread_setschedparam(pthread_self(), pSave->iPthreadPolicy, &pSave->PthreadSchedParam);
367	}
368
369
370	/**
371	* Starts a worker thread and wait for it to complete.
372	* We cannot use RTThreadCreate since we're already owner of the RW lock.
373	*/
374	static int rtSchedCreateThread(void (pfnThread)(void pvArg), void pvArg)
375	{
376	/*
377	* Setup thread attributes.
378	*/
379	pthread_attr_t ThreadAttr;
380	int rc = pthread_attr_init(&ThreadAttr);
381	if (!rc)
382	{
383	rc = pthread_attr_setdetachstate(&ThreadAttr, PTHREAD_CREATE_JOINABLE);
384	if (!rc)
385	{
386	rc = pthread_attr_setstacksize(&ThreadAttr, 128*1024);
387	if (!rc)
388	{
389	/*
390	* Create the thread.
391	*/
392	pthread_t Thread;
393	rc = pthread_create(&Thread, &ThreadAttr, pfnThread, pvArg);
394	if (!rc)
395	{
396	pthread_attr_destroy(&ThreadAttr);
397	/*
398	* Wait for the thread to finish.
399	*/
400	void pvRet = (void )-1;
401	do
402	{
403	rc = pthread_join(Thread, &pvRet);
404	} while (rc == EINTR);
405	if (rc)
406	return RTErrConvertFromErrno(rc);
407	return (int)(uintptr_t)pvRet;
408	}
409	}
410	}
411	pthread_attr_destroy(&ThreadAttr);
412	}
413	return RTErrConvertFromErrno(rc);
414	}
415
416
417	static void rtSchedDumpPriority(void)
418	{
419	#ifdef THREAD_LOGGING
420	Log(("Priority: g_fCanNice=%d g_enmOsPrioSup=%d\n", g_fCanNice, g_enmOsPrioSup));
421	Log(("Priority: enmPriority=%d \"%s\" iNice=%d iDelta=%d\n",
422	g_pProcessPriority->enmPriority,
423	g_pProcessPriority->pszName,
424	g_pProcessPriority->iNice,
425	g_pProcessPriority->iDelta));
426	Log(("Priority: %2d INFREQUENT_POLLER = %d\n", RTTHREADTYPE_INFREQUENT_POLLER, g_pProcessPriority->paTypes[RTTHREADTYPE_INFREQUENT_POLLER].iPriority));
427	Log(("Priority: %2d MAIN_HEAVY_WORKER = %d\n", RTTHREADTYPE_MAIN_HEAVY_WORKER, g_pProcessPriority->paTypes[RTTHREADTYPE_MAIN_HEAVY_WORKER].iPriority));
428	Log(("Priority: %2d EMULATION = %d\n", RTTHREADTYPE_EMULATION , g_pProcessPriority->paTypes[RTTHREADTYPE_EMULATION ].iPriority));
429	Log(("Priority: %2d DEFAULT = %d\n", RTTHREADTYPE_DEFAULT , g_pProcessPriority->paTypes[RTTHREADTYPE_DEFAULT ].iPriority));
430	Log(("Priority: %2d GUI = %d\n", RTTHREADTYPE_GUI , g_pProcessPriority->paTypes[RTTHREADTYPE_GUI ].iPriority));
431	Log(("Priority: %2d MAIN_WORKER = %d\n", RTTHREADTYPE_MAIN_WORKER , g_pProcessPriority->paTypes[RTTHREADTYPE_MAIN_WORKER ].iPriority));
432	Log(("Priority: %2d VRDP_IO = %d\n", RTTHREADTYPE_VRDP_IO , g_pProcessPriority->paTypes[RTTHREADTYPE_VRDP_IO ].iPriority));
433	Log(("Priority: %2d DEBUGGER = %d\n", RTTHREADTYPE_DEBUGGER , g_pProcessPriority->paTypes[RTTHREADTYPE_DEBUGGER ].iPriority));
434	Log(("Priority: %2d MSG_PUMP = %d\n", RTTHREADTYPE_MSG_PUMP , g_pProcessPriority->paTypes[RTTHREADTYPE_MSG_PUMP ].iPriority));
435	Log(("Priority: %2d IO = %d\n", RTTHREADTYPE_IO , g_pProcessPriority->paTypes[RTTHREADTYPE_IO ].iPriority));
436	Log(("Priority: %2d TIMER = %d\n", RTTHREADTYPE_TIMER , g_pProcessPriority->paTypes[RTTHREADTYPE_TIMER ].iPriority));
437	#endif
438	}
439
440
441	/**
442	* The prober thread.
443	* We don't want to mess with the priority of the calling thread.
444	*
445	* @remark This is pretty presumptive stuff, but if it works on Linux and
446	* FreeBSD it does what I want.
447	*/
448	static void rtSchedNativeProberThread(void pvUser)
449	{
450	SAVEDPRIORITY SavedPriority;
451	rtSchedNativeSave(&SavedPriority);
452
453	/*
454	* Let's first try and see what we get on a thread level.
455	*/
456	int iMax = sched_get_priority_max(SavedPriority.iPthreadPolicy);
457	int iMin = sched_get_priority_min(SavedPriority.iPthreadPolicy);
458	if (iMax - iMin >= 32)
459	{
460	pthread_t Self = pthread_self();
461	int i = iMin;
462	while (i <= iMax)
463	{
464	struct sched_param SchedParam = SavedPriority.PthreadSchedParam;
465	SchedParam.sched_priority = i;
466	if (pthread_setschedparam(Self, SavedPriority.iPthreadPolicy, &SchedParam))
467	break;
468	i++;
469	}
470	if (i == iMax)
471	g_enmOsPrioSup = OSPRIOSUP_PROCESS_AND_THREAD_LEVEL;
472	}
473
474	/*
475	* Ok, we didn't have the good stuff, so let's fall back on the unix stuff.
476	*/
477	if (g_enmOsPrioSup == OSPRIOSUP_UNDETERMINED)
478	g_enmOsPrioSup = OSPRIOSUP_THREAD_LEVEL;
479
480	/*
481	* Check if we can get higher priority (typically only root can do this).
482	* (Won't work right if our priority is -19 to start with, but what the heck.)
483	*
484	* We assume that the unix priority is -19 to 19. I know there are defines
485	* for this, but I don't remember which and if I'm awake enough to make sense
486	* of them from any SuS spec.
487	*/
488	int iStart = getpriority(PRIO_PROCESS, 0);
489	int i = iStart;
490	while (i-- > -19)
491	{
492	if (setpriority(PRIO_PROCESS, 0, i))
493	break;
494	}
495	if (getpriority(PRIO_PROCESS, 0) != iStart)
496	g_fCanNice = true;
497	else
498	g_fCanNice = false;
499
500	/* done */
501	rtSchedNativeRestore(&SavedPriority);
502	RT_NOREF(pvUser);
503	return (void *)VINF_SUCCESS;
504	}
505
506
507	/**
508	* Calculate the scheduling properties for all the threads in the default
509	* process priority, assuming the current thread have the type enmType.
510	*
511	* @returns iprt status code.
512	* @param enmType The thread type to be assumed for the current thread.
513	*/
514	DECLHIDDEN(int) rtSchedNativeCalcDefaultPriority(RTTHREADTYPE enmType)
515	{
516	Assert(enmType > RTTHREADTYPE_INVALID && enmType < RTTHREADTYPE_END);
517
518	/*
519	* First figure out what's supported by the OS.
520	*/
521	if (g_enmOsPrioSup == OSPRIOSUP_UNDETERMINED)
522	{
523	int iPriority = getpriority(PRIO_PROCESS, 0);
524	int rc = rtSchedCreateThread(rtSchedNativeProberThread, NULL);
525	if (RT_FAILURE(rc))
526	return rc;
527	if (g_enmOsPrioSup == OSPRIOSUP_UNDETERMINED)
528	g_enmOsPrioSup = OSPRIOSUP_THREAD_LEVEL;
529	Assert(getpriority(PRIO_PROCESS, 0) == iPriority); NOREF(iPriority);
530	}
531
532	/*
533	* Now let's see what we can do...
534	*/
535	int iPriority = getpriority(PRIO_PROCESS, 0);
536	switch (g_enmOsPrioSup)
537	{
538	case OSPRIOSUP_PROCESS_AND_THREAD_LEVEL:
539	{
540	g_aDefaultPriority.iNice = iPriority;
541	g_aDefaultPriority.iDelta = 0;
542	g_aDefaultPriority.paTypes = g_aTypesThread;
543	Assert(enmType == g_aDefaultPriority.paTypes[enmType].enmType);
544	break;
545	}
546
547	case OSPRIOSUP_THREAD_LEVEL:
548	{
549	if (g_fCanNice)
550	g_aDefaultPriority.paTypes = g_aTypesUnixFree;
551	else
552	g_aDefaultPriority.paTypes = g_aTypesUnixRestricted;
553	Assert(enmType == g_aDefaultPriority.paTypes[enmType].enmType);
554	g_aDefaultPriority.iNice = iPriority - g_aDefaultPriority.paTypes[enmType].iPriority;
555	g_aDefaultPriority.iDelta = g_aDefaultPriority.iNice;
556	break;
557	}
558
559	default:
560	AssertFailed();
561	break;
562	}
563	rtSchedDumpPriority();
564	return VINF_SUCCESS;
565	}
566
567
568	/**
569	* The validator thread.
570	* We don't want to mess with the priority of the calling thread.
571	*
572	* @remark This is pretty presumptive stuff, but if it works on Linux and
573	* FreeBSD it does what I want.
574	*/
575	static void rtSchedNativeValidatorThread(void pvUser)
576	{
577	const PROCPRIORITY pCfg = (const PROCPRIORITY )pvUser;
578	SAVEDPRIORITY SavedPriority;
579	rtSchedNativeSave(&SavedPriority);
580
581	int rc = VINF_SUCCESS;
582	switch (g_enmOsPrioSup)
583	{
584	/*
585	* Try set the specified process priority and then try
586	* out all the thread priorities which are used.
587	*/
588	case OSPRIOSUP_PROCESS_AND_THREAD_LEVEL:
589	{
590	if (!setpriority(PRIO_PROCESS, 0, pCfg->iNice))
591	{
592	int iMin = sched_get_priority_min(SavedPriority.iPolicy);
593	pthread_t Self = pthread_self();
594	for (int i = RTTHREADTYPE_INVALID + 1; i < RTTHREADTYPE_END; i++)
595	{
596	struct sched_param SchedParam = SavedPriority.PthreadSchedParam;
597	SchedParam.sched_priority = pCfg->paTypes[i].iPriority
598	+ pCfg->iDelta + iMin;
599	rc = pthread_setschedparam(Self, SavedPriority.iPthreadPolicy, &SchedParam);
600	if (rc)
601	{
602	rc = RTErrConvertFromErrno(rc);
603	break;
604	}
605	}
606	}
607	else
608	rc = RTErrConvertFromErrno(errno);
609	break;
610	}
611
612	/*
613	* Try out the priorities from the top and down.
614	*/
615	case OSPRIOSUP_THREAD_LEVEL:
616	{
617	int i = RTTHREADTYPE_END;
618	while (--i > RTTHREADTYPE_INVALID)
619	{
620	int iPriority = pCfg->paTypes[i].iPriority + pCfg->iDelta;
621	if (setpriority(PRIO_PROCESS, 0, iPriority))
622	{
623	rc = RTErrConvertFromErrno(errno);
624	break;
625	}
626	}
627	break;
628	}
629
630	default:
631	AssertFailed();
632	break;
633	}
634
635	/* done */
636	rtSchedNativeRestore(&SavedPriority);
637	return (void *)(intptr_t)rc;
638	}
639
640
641	/**
642	* Validates and sets the process priority.
643	* This will check that all rtThreadNativeSetPriority() will success for all the
644	* thread types when applied to the current thread.
645	*
646	* @returns iprt status code.
647	* @param enmPriority The priority to validate and set.
648	*/
649	DECLHIDDEN(int) rtProcNativeSetPriority(RTPROCPRIORITY enmPriority)
650	{
651	Assert(enmPriority > RTPROCPRIORITY_INVALID && enmPriority < RTPROCPRIORITY_LAST);
652
653	#ifdef RTTHREAD_POSIX_WITH_CREATE_PRIORITY_PROXY
654	/*
655	* Make sure the proxy creation thread is started so we don't 'lose' our
656	* initial priority if it's lowered.
657	*/
658	rtThreadPosixPriorityProxyStart();
659	#endif
660
661	/*
662	* Nothing to validate for the default priority (assuming no external renice).
663	*/
664	int rc = VINF_SUCCESS;
665	if (enmPriority == RTPROCPRIORITY_DEFAULT)
666	g_pProcessPriority = &g_aDefaultPriority;
667	else
668	{
669	/*
670	* Select the array to search.
671	*/
672	const PROCPRIORITY *pa;
673	unsigned c;
674	switch (g_enmOsPrioSup)
675	{
676	case OSPRIOSUP_PROCESS_AND_THREAD_LEVEL:
677	pa = g_aProcessAndThread;
678	c = RT_ELEMENTS(g_aProcessAndThread);
679	break;
680	case OSPRIOSUP_THREAD_LEVEL:
681	pa = g_aUnixConfigs;
682	c = RT_ELEMENTS(g_aUnixConfigs);
683	break;
684	default:
685	pa = NULL;
686	c = 0;
687	break;
688	}
689
690	/*
691	* Search the array.
692	*/
693	rc = VERR_FILE_NOT_FOUND;
694	unsigned i;
695	for (i = 0; i < c; i++)
696	{
697	if (pa[i].enmPriority == enmPriority)
698	{
699	/*
700	* Validate it.
701	*/
702	int iPriority = getpriority(PRIO_PROCESS, 0);
703	int rc3 = rtSchedCreateThread(rtSchedNativeValidatorThread, (void *)&pa[i]);
704	Assert(getpriority(PRIO_PROCESS, 0) == iPriority); NOREF(iPriority);
705	if (RT_SUCCESS(rc))
706	rc = rc3;
707	if (RT_SUCCESS(rc))
708	break;
709	}
710	}
711
712	/*
713	* Did we get lucky?
714	* If so update process priority and globals.
715	*/
716	if (RT_SUCCESS(rc))
717	{
718	switch (g_enmOsPrioSup)
719	{
720	case OSPRIOSUP_PROCESS_AND_THREAD_LEVEL:
721	if (setpriority(PRIO_PROCESS, 0, pa[i].iNice))
722	{
723	rc = RTErrConvertFromErrno(errno);
724	AssertMsgFailed(("setpriority(,,%d) -> errno=%d rc=%Rrc\n", pa[i].iNice, errno, rc));
725	}
726	break;
727
728	default:
729	break;
730	}
731
732	if (RT_SUCCESS(rc))
733	g_pProcessPriority = &pa[i];
734	}
735	}
736
737	#ifdef THREAD_LOGGING
738	LogFlow(("rtProcNativeSetPriority: returns %Rrc enmPriority=%d\n", rc, enmPriority));
739	rtSchedDumpPriority();
740	#endif
741	return rc;
742	}
743
744
745	/**
746	* Worker for rtThreadNativeSetPriority/OSPRIOSUP_PROCESS_AND_THREAD_LEVEL
747	* that's either called on the priority proxy thread or directly if no proxy.
748	*/
749	static DECLCALLBACK(int) rtThreadPosixSetPriorityOnProcAndThrdCallback(PRTTHREADINT pThread, RTTHREADTYPE enmType)
750	{
751	struct sched_param SchedParam = {-9999999};
752	int iPolicy = -7777777;
753	int rc = pthread_getschedparam((pthread_t)pThread->Core.Key, &iPolicy, &SchedParam);
754	if (!rc)
755	{
756	SchedParam.sched_priority = g_pProcessPriority->paTypes[enmType].iPriority
757	+ g_pProcessPriority->iDelta
758	+ sched_get_priority_min(iPolicy);
759
760	rc = pthread_setschedparam((pthread_t)pThread->Core.Key, iPolicy, &SchedParam);
761	if (!rc)
762	{
763	#ifdef THREAD_LOGGING
764	Log(("rtThreadNativeSetPriority: Thread=%p enmType=%d iPolicy=%d sched_priority=%d pid=%d\n",
765	pThread->Core.Key, enmType, iPolicy, SchedParam.sched_priority, getpid()));
766	#endif
767	return VINF_SUCCESS;
768	}
769	}
770
771	int rcNative = rc;
772	rc = RTErrConvertFromErrno(rc);
773	AssertMsgFailed(("pthread_[gs]etschedparam(%p, %d, {%d}) -> rcNative=%d rc=%Rrc\n",
774	(void *)pThread->Core.Key, iPolicy, SchedParam.sched_priority, rcNative, rc)); NOREF(rcNative);
775	return rc;
776	}
777
778
779	/**
780	* Sets the priority of the thread according to the thread type
781	* and current process priority.
782	*
783	* The RTTHREADINT::enmType member has not yet been updated and will be updated by
784	* the caller on a successful return.
785	*
786	* @returns iprt status code.
787	* @param Thread The thread in question.
788	* @param enmType The thread type.
789	*/
790	DECLHIDDEN(int) rtThreadNativeSetPriority(PRTTHREADINT pThread, RTTHREADTYPE enmType)
791	{
792	Assert(enmType > RTTHREADTYPE_INVALID && enmType < RTTHREADTYPE_END);
793	Assert(enmType == g_pProcessPriority->paTypes[enmType].enmType);
794
795	int rc = VINF_SUCCESS;
796	switch (g_enmOsPrioSup)
797	{
798	case OSPRIOSUP_PROCESS_AND_THREAD_LEVEL:
799	{
800	#ifdef RTTHREAD_POSIX_WITH_CREATE_PRIORITY_PROXY
801	if (rtThreadPosixPriorityProxyStart())
802	rc = rtThreadPosixPriorityProxyCall(pThread, (PFNRT)rtThreadPosixSetPriorityOnProcAndThrdCallback,
803	2, pThread, enmType);
804	else
805	#endif
806	rc = rtThreadPosixSetPriorityOnProcAndThrdCallback(pThread, enmType);
807	break;
808	}
809
810	case OSPRIOSUP_THREAD_LEVEL:
811	{
812	/* No cross platform way of getting the 'who' parameter value for
813	arbitrary threads, so this is restricted to the calling thread only. */
814	AssertReturn((pthread_t)pThread->Core.Key == pthread_self(), VERR_NOT_SUPPORTED);
815
816	int iPriority = g_pProcessPriority->paTypes[enmType].iPriority + g_pProcessPriority->iDelta;
817	if (!setpriority(PRIO_PROCESS, 0, iPriority))
818	{
819	AssertMsg(iPriority == getpriority(PRIO_PROCESS, 0), ("iPriority=%d getpriority()=%d\n", iPriority, getpriority(PRIO_PROCESS, 0)));
820	#ifdef THREAD_LOGGING
821	Log(("rtThreadNativeSetPriority: Thread=%p enmType=%d iPriority=%d pid=%d\n", pThread->Core.Key, enmType, iPriority, getpid()));
822	#endif
823	}
824	else
825	{
826	#if 0
827	rc = RTErrConvertFromErrno(errno);
828	AssertMsgFailed(("setpriority(,, %d) -> errno=%d rc=%Rrc\n", iPriority, errno, rc));
829	#else
830	/** @todo
831	* Just keep quiet about failures now - we'll fail here because we're not
832	* allowed to raise our own priority. This is a problem when starting the
833	* threads with higher priority from EMT (i.e. most threads it starts).
834	* This is apparently inherited from the parent in some cases and not
835	* in other cases. I guess this would come down to which kind of pthread
836	* implementation is actually in use, and how many sensible patches which
837	* are installed.
838	* I need to find a system where this problem shows up in order to come up
839	* with a proper fix. There's an pthread_create attribute for not inheriting
840	* scheduler stuff I think...
841	*/
842	rc = VINF_SUCCESS;
843	#endif
844	}
845	break;
846	}
847
848	/*
849	* Any thread created before we determine the default config, remains unchanged!
850	* The prober thread above is one of those.
851	*/
852	default:
853	break;
854	}
855
856	return rc;
857	}
858

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source: vbox/trunk/src/VBox/Runtime/r3/posix/sched-posix.cpp@ 82660

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