1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
|
/***************************************************************************
* Copyright (c) 2024 Microsoft Corporation
* Copyright (c) 2026-present Eclipse ThreadX contributors
*
* This program and the accompanying materials are made available under the
* terms of the MIT License which is available at
* https://opensource.org/licenses/MIT.
*
* SPDX-License-Identifier: MIT
**************************************************************************/
/**************************************************************************/
/**************************************************************************/
/** */
/** ThreadX Component */
/** */
/** Thread - High Level SMP Support */
/** */
/**************************************************************************/
/**************************************************************************/
#define TX_SOURCE_CODE
#define TX_THREAD_SMP_SOURCE_CODE
/* Include necessary system files. */
#include "tx_api.h"
#include "tx_initialize.h"
#include "tx_timer.h"
#include "tx_thread.h"
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _tx_thread_smp_rebalance_execute_list PORTABLE SMP */
/* 6.1 */
/* AUTHOR */
/* */
/* William E. Lamie, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function is responsible for mapping ready ThreadX threads with */
/* cores in the SMP . The basic idea is the standard ThreadX */
/* ready list is traversed to build the _tx_thread_execute_ptr list. */
/* Each index represents the and the corresponding entry in this */
/* array contains the thread that should be executed by that core. If */
/* the was previously running a different thread, it will be */
/* preempted and restarted so it can run the new thread. */
/* */
/* INPUT */
/* */
/* None */
/* */
/* OUTPUT */
/* */
/* None */
/* */
/* CALLS */
/* */
/* _tx_thread_smp_execute_list_clear Clear the thread execute list */
/* _tx_thread_smp_execute_list_setup Setup the thread execute list */
/* _tx_thread_smp_next_priority_find Find next priority with one */
/* or more ready threads */
/* _tx_thread_smp_remap_solution_find Attempt to remap threads to */
/* schedule another thread */
/* _tx_thread_smp_schedule_list_clear Clear the thread schedule list*/
/* */
/* CALLED BY */
/* */
/* _tx_mutex_priority_change Mutex priority change */
/* _tx_thread_create Thread create */
/* _tx_thread_preemption_change Thread preemption change */
/* _tx_thread_priority_change Thread priority change */
/* _tx_thread_relinquish Thread relinquish */
/* _tx_thread_resume Thread resume */
/* _tx_thread_smp_core_exclude Thread SMP core exclude */
/* _tx_thread_system_resume Thread system resume */
/* _tx_thread_system_suspend Thread suspend */
/* _tx_thread_time_slice Thread time-slice */
/* */
/**************************************************************************/
void _tx_thread_smp_rebalance_execute_list(UINT core_index)
{
UINT i, j, core;
UINT next_priority;
UINT last_priority;
TX_THREAD *schedule_thread;
#ifdef TX_THREAD_ENABLE_PERFORMANCE_INFO
TX_THREAD *mapped_thread;
#endif
TX_THREAD *preempted_thread;
ULONG possible_cores;
ULONG thread_possible_cores;
ULONG available_cores;
ULONG test_possible_cores;
ULONG test_cores;
UINT this_pass_complete;
UINT loop_finished;
#ifdef TX_THREAD_SMP_EQUAL_PRIORITY
TX_THREAD *highest_priority_thread;
#endif
#ifndef TX_DISABLE_PREEMPTION_THRESHOLD
ULONG priority_bit;
#if TX_MAX_PRIORITIES > 32
UINT map_index;
#endif
#endif
/* It is assumed that the preempt disable flag is still set at this point. */
/* Pickup the last schedule thread with preemption-threshold enabled. */
preempted_thread = _tx_thread_preemption__threshold_scheduled;
/* Clear the schedule list. */
_tx_thread_smp_schedule_list_clear();
/* Initialize the next priority to 0, the highest priority. */
next_priority = ((UINT) 0);
/* Initialize the last priority. */
last_priority = ((UINT) 0);
#ifndef TX_THREAD_SMP_DYNAMIC_CORE_MAX
/* Set the possible cores bit map to all cores. */
possible_cores = ((ULONG) TX_THREAD_SMP_CORE_MASK);
#else
/* Set the possible cores bit map to all cores. */
possible_cores = (((ULONG) 1) << _tx_thread_smp_max_cores) - 1;
#endif
/* Setup the available cores bit map. */
available_cores = possible_cores;
/* Clear the schedule thread pointer. */
schedule_thread = TX_NULL;
#ifdef TX_THREAD_SMP_EQUAL_PRIORITY
/* Set the highest priority thread to NULL. */
highest_priority_thread = TX_NULL;
#endif
/* Loop to rebuild the schedule list. */
i = ((UINT) 0);
loop_finished = TX_FALSE;
do
{
/* Clear the pass complete flag, which is used to skip the remaining processing
of this loop on certain conditions. */
this_pass_complete = TX_FALSE;
/* Determine if there is a thread to schedule. */
if (schedule_thread == TX_NULL)
{
/* Calculate the next ready priority. */
next_priority = _tx_thread_smp_next_priority_find(next_priority);
/* Determine if there are no more threads to execute. */
if (next_priority == ((UINT) TX_MAX_PRIORITIES))
{
/* Break out of loop. */
loop_finished = TX_TRUE;
this_pass_complete = TX_TRUE;
}
else
{
/* Determine if a thread was executed with preemption-threshold set. */
if (preempted_thread != TX_NULL)
{
/* Yes, a thread was previously preempted. Let's first see if we reached the
interrupted preemption-threshold level. */
if (next_priority >= preempted_thread -> tx_thread_preempt_threshold)
{
/* Yes, now lets see if we are within the preemption-threshold level. */
if (next_priority <= preempted_thread -> tx_thread_priority)
{
/* Yes, move the next priority to the preempted priority. */
next_priority = preempted_thread -> tx_thread_priority;
/* Setup the schedule thread to the preempted thread. */
schedule_thread = preempted_thread;
/* Start at the top of the loop. */
this_pass_complete = TX_TRUE;
}
else
{
/* Nothing else is allowed to execute after the preemption-threshold thread. */
next_priority = ((UINT) TX_MAX_PRIORITIES);
/* Break out of loop. */
loop_finished = TX_TRUE;
this_pass_complete = TX_TRUE;
}
}
}
}
/* Determine if this pass through the loop is already complete. */
if (this_pass_complete == TX_FALSE)
{
/* Pickup the next thread to schedule. */
schedule_thread = _tx_thread_priority_list[next_priority];
}
}
/* Determine if this pass through the loop is already complete. */
if (this_pass_complete == TX_FALSE)
{
/* Determine what the possible cores are for this thread. */
thread_possible_cores = schedule_thread -> tx_thread_smp_cores_allowed;
/* Apply the current possible cores. */
thread_possible_cores = thread_possible_cores & (available_cores | possible_cores);
/* Determine if it is possible to schedule this thread. */
if (thread_possible_cores == ((ULONG) 0))
{
/* No, this thread can't be scheduled. */
/* Look at the next thread at the same priority level. */
schedule_thread = schedule_thread -> tx_thread_ready_next;
/* Determine if this is the head of the list. */
if (schedule_thread == _tx_thread_priority_list[next_priority])
{
/* Set the schedule thread to NULL to force examination of the next priority level. */
schedule_thread = TX_NULL;
/* Move to the next priority level. */
next_priority++;
/* Determine if there are no more threads to execute. */
if (next_priority == ((UINT) TX_MAX_PRIORITIES))
{
/* Break out of loop. */
loop_finished = TX_TRUE;
}
}
}
else
{
/* It is possible to schedule this thread. */
/* Determine if this thread has preemption-threshold set. */
if (schedule_thread -> tx_thread_preempt_threshold < schedule_thread -> tx_thread_priority)
{
/* Yes, preemption-threshold is set. */
/* Determine if the last priority is above the preemption-threshold. If not, we can't
schedule this thread with preemption-threshold set. */
if ((last_priority >= schedule_thread -> tx_thread_preempt_threshold) && (i != ((UINT) 0)))
{
/* A thread was found that violates the next thread to be scheduled's preemption-threshold. We will simply
skip this thread and see if there is anything else we can schedule. */
/* Look at the next thread at the same priority level. */
schedule_thread = schedule_thread -> tx_thread_ready_next;
/* Determine if this is the head of the list. */
if (schedule_thread == _tx_thread_priority_list[next_priority])
{
/* Set the schedule thread to NULL to force examination of the next priority level. */
schedule_thread = TX_NULL;
/* Move to the next priority level. */
next_priority++;
/* Determine if there are no more threads to execute. */
if (next_priority == ((UINT) TX_MAX_PRIORITIES))
{
/* Break out of loop. */
loop_finished = TX_TRUE;
}
}
/* Restart the loop. */
this_pass_complete = TX_TRUE;
}
}
/* Determine if this pass through the loop is already complete. */
if (this_pass_complete == TX_FALSE)
{
#ifdef TX_THREAD_ENABLE_PERFORMANCE_INFO
/* Initialize index to an invalid value. */
j = ((UINT) TX_THREAD_SMP_MAX_CORES);
#endif
/* Determine if there is an available core for this thread to execute on. */
if ((thread_possible_cores & available_cores) != ((ULONG) 0))
{
/* Pickup the last executed core for this thread. */
j = schedule_thread -> tx_thread_smp_core_mapped;
/* Is this core valid and available? */
if ((thread_possible_cores & available_cores & (((ULONG) 1) << j)) == ((ULONG) 0))
{
/* No, we must find the next core for this thread. */
test_cores = (thread_possible_cores & available_cores);
TX_LOWEST_SET_BIT_CALCULATE(test_cores, j)
/* Setup the last executed core for this thread. */
schedule_thread -> tx_thread_smp_core_mapped = j;
}
/* Place the this thread on this core. */
_tx_thread_smp_schedule_list[j] = schedule_thread;
/* Clear the associated available cores bit. */
available_cores = available_cores & ~(((ULONG) 1) << j);
}
else
{
/* Note that we know that the thread must have at least one core excluded at this point,
since we didn't find a match and we have available cores. */
/* Now we need to see if one of the other threads in the non-excluded cores can be moved to make room
for this thread. */
/* Determine the possible core remapping attempt. */
test_possible_cores = possible_cores & ~(thread_possible_cores);
/* Attempt to remap the cores in order to schedule this thread. */
core = _tx_thread_smp_remap_solution_find(schedule_thread, available_cores, thread_possible_cores, test_possible_cores);
/* Determine if remapping was successful. */
if (core != ((UINT) TX_THREAD_SMP_MAX_CORES))
{
/* Yes, remapping was successful. Update the available cores accordingly. */
available_cores = available_cores & ~(((ULONG) 1) << core);
}
else
{
/* We couldn't assign the thread to any of the cores possible for the thread. */
/* Check to see if the thread is the last thread preempted. */
if (schedule_thread == preempted_thread)
{
/* To honor the preemption-threshold, we cannot schedule any more threads. */
loop_finished = TX_TRUE;
}
else
{
/* update the available cores for the next pass so we don't waste time looking at them again! */
possible_cores = possible_cores & (~thread_possible_cores);
/* No, we couldn't load the thread because none of the required cores were available. Look at the next thread at the same priority level. */
schedule_thread = schedule_thread -> tx_thread_ready_next;
/* Determine if this is the head of the list. */
if (schedule_thread == _tx_thread_priority_list[next_priority])
{
/* Set the schedule thread to NULL to force examination of the next priority level. */
schedule_thread = TX_NULL;
/* Move to the next priority level. */
next_priority++;
/* Determine if there are no more threads to execute. */
if (next_priority == ((UINT) TX_MAX_PRIORITIES))
{
/* Break out of loop. */
loop_finished = TX_TRUE;
}
}
}
/* Restart the loop. */
this_pass_complete = TX_TRUE;
}
}
/* Determine if this pass through the loop is already complete. */
if (this_pass_complete == TX_FALSE)
{
#ifdef TX_THREAD_SMP_EQUAL_PRIORITY
/* Determine if this is the highest priority thread. */
if (highest_priority_thread == TX_NULL)
{
/* No highest priority yet, remember this thread. */
highest_priority_thread = schedule_thread;
}
#endif
/* Increment the number of threads loaded. */
i++;
#ifdef TX_THREAD_ENABLE_PERFORMANCE_INFO
/* Determine if the thread was mapped. */
if (j != ((UINT) TX_THREAD_SMP_MAX_CORES))
{
/* Pickup the currently mapped thread. */
mapped_thread = _tx_thread_execute_ptr[j];
/* Determine if preemption is present. */
if ((mapped_thread != TX_NULL) && (schedule_thread != mapped_thread))
{
/* Determine if the previously mapped thread is still ready. */
if (mapped_thread -> tx_thread_state == TX_READY)
{
/* Determine if the caller is an interrupt or from a thread. */
if (_tx_thread_system_state[core_index] == ((ULONG) 0))
{
/* Caller is a thread, so this is a solicited preemption. */
_tx_thread_performance_solicited_preemption_count++;
/* Increment the thread's solicited preemption counter. */
mapped_thread -> tx_thread_performance_solicited_preemption_count++;
}
else
{
/* Is this an interrupt? */
if (_tx_thread_system_state[core_index] < TX_INITIALIZE_IN_PROGRESS)
{
/* Caller is an interrupt, so this is an interrupt preemption. */
_tx_thread_performance_interrupt_preemption_count++;
/* Increment the thread's interrupt preemption counter. */
mapped_thread -> tx_thread_performance_interrupt_preemption_count++;
}
}
}
}
}
#endif
/* Determine if this thread has preemption-threshold set. */
if (schedule_thread -> tx_thread_preempt_threshold < schedule_thread -> tx_thread_priority)
{
#ifndef TX_DISABLE_PREEMPTION_THRESHOLD
/* mark the bit map to show that a thread with preemption-threshold has been executed. */
#if TX_MAX_PRIORITIES > 32
/* Calculate the index into the bit map array. */
map_index = (schedule_thread -> tx_thread_priority)/((UINT) 32);
/* Set the active bit to remember that the preempt map has something set. */
TX_DIV32_BIT_SET(schedule_thread -> tx_thread_priority, priority_bit)
_tx_thread_preempted_map_active = _tx_thread_preempted_map_active | priority_bit;
#endif
/* Remember that this thread was executed with preemption-threshold set. */
TX_MOD32_BIT_SET(schedule_thread -> tx_thread_priority, priority_bit)
_tx_thread_preempted_maps[MAP_INDEX] = _tx_thread_preempted_maps[MAP_INDEX] | priority_bit;
/* Place the thread in the preempted list indicating preemption-threshold is in force. */
_tx_thread_preemption_threshold_list[schedule_thread -> tx_thread_priority] = schedule_thread;
#endif
/* Set the last thread with preemption-threshold enabled. */
_tx_thread_preemption__threshold_scheduled = schedule_thread;
/* Now break out of the scheduling loop. */
loop_finished = TX_TRUE;
}
else
{
/* Remember the last priority. */
last_priority = next_priority;
/* Pickup the next ready thread at the current priority level. */
schedule_thread = schedule_thread -> tx_thread_ready_next;
/* Determine if this is the head of the list, which implies that we have exhausted this priority level. */
if (schedule_thread == _tx_thread_priority_list[next_priority])
{
/* Set the schedule thread to NULL to force examination of the next priority level. */
schedule_thread = TX_NULL;
/* Move to the next priority level. */
next_priority++;
#ifdef TX_THREAD_SMP_EQUAL_PRIORITY
/* Determine if there is a highest priority thread. */
if (highest_priority_thread)
{
/* Yes, break out of the loop, since only same priority threads can be
scheduled in this mode. */
loop_finished = TX_TRUE;
}
#endif
/* Determine if there are no more threads to execute. */
if (next_priority == ((UINT) TX_MAX_PRIORITIES))
{
/* Break out of loop. */
loop_finished = TX_TRUE;
}
}
}
}
}
}
}
/* Determine if the loop is finished. */
if (loop_finished == TX_TRUE)
{
/* Finished, break the loop. */
break;
}
#ifndef TX_THREAD_SMP_DYNAMIC_CORE_MAX
} while (i < ((UINT) TX_THREAD_SMP_MAX_CORES));
#else
} while (i < _tx_thread_smp_max_cores);
#endif
/* Clear the execute list. */
_tx_thread_smp_execute_list_clear();
/* Setup the execute list based on the updated schedule list. */
_tx_thread_smp_execute_list_setup(core_index);
}
|
