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d6d71ee4 JP |
1 | /* |
2 | * intel_powerclamp.c - package c-state idle injection | |
3 | * | |
4 | * Copyright (c) 2012, Intel Corporation. | |
5 | * | |
6 | * Authors: | |
7 | * Arjan van de Ven <arjan@linux.intel.com> | |
8 | * Jacob Pan <jacob.jun.pan@linux.intel.com> | |
9 | * | |
10 | * This program is free software; you can redistribute it and/or modify it | |
11 | * under the terms and conditions of the GNU General Public License, | |
12 | * version 2, as published by the Free Software Foundation. | |
13 | * | |
14 | * This program is distributed in the hope it will be useful, but WITHOUT | |
15 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
16 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
17 | * more details. | |
18 | * | |
19 | * You should have received a copy of the GNU General Public License along with | |
20 | * this program; if not, write to the Free Software Foundation, Inc., | |
21 | * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA. | |
22 | * | |
23 | * | |
24 | * TODO: | |
25 | * 1. better handle wakeup from external interrupts, currently a fixed | |
26 | * compensation is added to clamping duration when excessive amount | |
27 | * of wakeups are observed during idle time. the reason is that in | |
28 | * case of external interrupts without need for ack, clamping down | |
29 | * cpu in non-irq context does not reduce irq. for majority of the | |
30 | * cases, clamping down cpu does help reduce irq as well, we should | |
31 | * be able to differenciate the two cases and give a quantitative | |
32 | * solution for the irqs that we can control. perhaps based on | |
33 | * get_cpu_iowait_time_us() | |
34 | * | |
35 | * 2. synchronization with other hw blocks | |
36 | * | |
37 | * | |
38 | */ | |
39 | ||
40 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt | |
41 | ||
42 | #include <linux/module.h> | |
43 | #include <linux/kernel.h> | |
44 | #include <linux/delay.h> | |
45 | #include <linux/kthread.h> | |
46 | #include <linux/freezer.h> | |
47 | #include <linux/cpu.h> | |
48 | #include <linux/thermal.h> | |
49 | #include <linux/slab.h> | |
50 | #include <linux/tick.h> | |
51 | #include <linux/debugfs.h> | |
52 | #include <linux/seq_file.h> | |
19cc90f5 | 53 | #include <linux/sched/rt.h> |
d6d71ee4 JP |
54 | |
55 | #include <asm/nmi.h> | |
56 | #include <asm/msr.h> | |
57 | #include <asm/mwait.h> | |
58 | #include <asm/cpu_device_id.h> | |
59 | #include <asm/idle.h> | |
60 | #include <asm/hardirq.h> | |
61 | ||
62 | #define MAX_TARGET_RATIO (50U) | |
63 | /* For each undisturbed clamping period (no extra wake ups during idle time), | |
64 | * we increment the confidence counter for the given target ratio. | |
65 | * CONFIDENCE_OK defines the level where runtime calibration results are | |
66 | * valid. | |
67 | */ | |
68 | #define CONFIDENCE_OK (3) | |
69 | /* Default idle injection duration, driver adjust sleep time to meet target | |
70 | * idle ratio. Similar to frequency modulation. | |
71 | */ | |
72 | #define DEFAULT_DURATION_JIFFIES (6) | |
73 | ||
74 | static unsigned int target_mwait; | |
75 | static struct dentry *debug_dir; | |
76 | ||
77 | /* user selected target */ | |
78 | static unsigned int set_target_ratio; | |
79 | static unsigned int current_ratio; | |
80 | static bool should_skip; | |
81 | static bool reduce_irq; | |
82 | static atomic_t idle_wakeup_counter; | |
83 | static unsigned int control_cpu; /* The cpu assigned to collect stat and update | |
84 | * control parameters. default to BSP but BSP | |
85 | * can be offlined. | |
86 | */ | |
87 | static bool clamping; | |
88 | ||
89 | ||
90 | static struct task_struct * __percpu *powerclamp_thread; | |
91 | static struct thermal_cooling_device *cooling_dev; | |
92 | static unsigned long *cpu_clamping_mask; /* bit map for tracking per cpu | |
93 | * clamping thread | |
94 | */ | |
95 | ||
96 | static unsigned int duration; | |
97 | static unsigned int pkg_cstate_ratio_cur; | |
98 | static unsigned int window_size; | |
99 | ||
100 | static int duration_set(const char *arg, const struct kernel_param *kp) | |
101 | { | |
102 | int ret = 0; | |
103 | unsigned long new_duration; | |
104 | ||
105 | ret = kstrtoul(arg, 10, &new_duration); | |
106 | if (ret) | |
107 | goto exit; | |
108 | if (new_duration > 25 || new_duration < 6) { | |
109 | pr_err("Out of recommended range %lu, between 6-25ms\n", | |
110 | new_duration); | |
111 | ret = -EINVAL; | |
112 | } | |
113 | ||
114 | duration = clamp(new_duration, 6ul, 25ul); | |
115 | smp_mb(); | |
116 | ||
117 | exit: | |
118 | ||
119 | return ret; | |
120 | } | |
121 | ||
122 | static struct kernel_param_ops duration_ops = { | |
123 | .set = duration_set, | |
124 | .get = param_get_int, | |
125 | }; | |
126 | ||
127 | ||
128 | module_param_cb(duration, &duration_ops, &duration, 0644); | |
129 | MODULE_PARM_DESC(duration, "forced idle time for each attempt in msec."); | |
130 | ||
131 | struct powerclamp_calibration_data { | |
132 | unsigned long confidence; /* used for calibration, basically a counter | |
133 | * gets incremented each time a clamping | |
134 | * period is completed without extra wakeups | |
135 | * once that counter is reached given level, | |
136 | * compensation is deemed usable. | |
137 | */ | |
138 | unsigned long steady_comp; /* steady state compensation used when | |
139 | * no extra wakeups occurred. | |
140 | */ | |
141 | unsigned long dynamic_comp; /* compensate excessive wakeup from idle | |
142 | * mostly from external interrupts. | |
143 | */ | |
144 | }; | |
145 | ||
146 | static struct powerclamp_calibration_data cal_data[MAX_TARGET_RATIO]; | |
147 | ||
148 | static int window_size_set(const char *arg, const struct kernel_param *kp) | |
149 | { | |
150 | int ret = 0; | |
151 | unsigned long new_window_size; | |
152 | ||
153 | ret = kstrtoul(arg, 10, &new_window_size); | |
154 | if (ret) | |
155 | goto exit_win; | |
156 | if (new_window_size > 10 || new_window_size < 2) { | |
157 | pr_err("Out of recommended window size %lu, between 2-10\n", | |
158 | new_window_size); | |
159 | ret = -EINVAL; | |
160 | } | |
161 | ||
162 | window_size = clamp(new_window_size, 2ul, 10ul); | |
163 | smp_mb(); | |
164 | ||
165 | exit_win: | |
166 | ||
167 | return ret; | |
168 | } | |
169 | ||
170 | static struct kernel_param_ops window_size_ops = { | |
171 | .set = window_size_set, | |
172 | .get = param_get_int, | |
173 | }; | |
174 | ||
175 | module_param_cb(window_size, &window_size_ops, &window_size, 0644); | |
176 | MODULE_PARM_DESC(window_size, "sliding window in number of clamping cycles\n" | |
177 | "\tpowerclamp controls idle ratio within this window. larger\n" | |
178 | "\twindow size results in slower response time but more smooth\n" | |
179 | "\tclamping results. default to 2."); | |
180 | ||
181 | static void find_target_mwait(void) | |
182 | { | |
183 | unsigned int eax, ebx, ecx, edx; | |
184 | unsigned int highest_cstate = 0; | |
185 | unsigned int highest_subcstate = 0; | |
186 | int i; | |
187 | ||
188 | if (boot_cpu_data.cpuid_level < CPUID_MWAIT_LEAF) | |
189 | return; | |
190 | ||
191 | cpuid(CPUID_MWAIT_LEAF, &eax, &ebx, &ecx, &edx); | |
192 | ||
193 | if (!(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED) || | |
194 | !(ecx & CPUID5_ECX_INTERRUPT_BREAK)) | |
195 | return; | |
196 | ||
197 | edx >>= MWAIT_SUBSTATE_SIZE; | |
198 | for (i = 0; i < 7 && edx; i++, edx >>= MWAIT_SUBSTATE_SIZE) { | |
199 | if (edx & MWAIT_SUBSTATE_MASK) { | |
200 | highest_cstate = i; | |
201 | highest_subcstate = edx & MWAIT_SUBSTATE_MASK; | |
202 | } | |
203 | } | |
204 | target_mwait = (highest_cstate << MWAIT_SUBSTATE_SIZE) | | |
205 | (highest_subcstate - 1); | |
206 | ||
207 | } | |
208 | ||
7734e3ac YS |
209 | static bool has_pkg_state_counter(void) |
210 | { | |
211 | u64 tmp; | |
212 | return !rdmsrl_safe(MSR_PKG_C2_RESIDENCY, &tmp) || | |
213 | !rdmsrl_safe(MSR_PKG_C3_RESIDENCY, &tmp) || | |
214 | !rdmsrl_safe(MSR_PKG_C6_RESIDENCY, &tmp) || | |
215 | !rdmsrl_safe(MSR_PKG_C7_RESIDENCY, &tmp); | |
216 | } | |
217 | ||
d6d71ee4 JP |
218 | static u64 pkg_state_counter(void) |
219 | { | |
220 | u64 val; | |
221 | u64 count = 0; | |
222 | ||
223 | static bool skip_c2; | |
224 | static bool skip_c3; | |
225 | static bool skip_c6; | |
226 | static bool skip_c7; | |
227 | ||
228 | if (!skip_c2) { | |
229 | if (!rdmsrl_safe(MSR_PKG_C2_RESIDENCY, &val)) | |
230 | count += val; | |
231 | else | |
232 | skip_c2 = true; | |
233 | } | |
234 | ||
235 | if (!skip_c3) { | |
236 | if (!rdmsrl_safe(MSR_PKG_C3_RESIDENCY, &val)) | |
237 | count += val; | |
238 | else | |
239 | skip_c3 = true; | |
240 | } | |
241 | ||
242 | if (!skip_c6) { | |
243 | if (!rdmsrl_safe(MSR_PKG_C6_RESIDENCY, &val)) | |
244 | count += val; | |
245 | else | |
246 | skip_c6 = true; | |
247 | } | |
248 | ||
249 | if (!skip_c7) { | |
250 | if (!rdmsrl_safe(MSR_PKG_C7_RESIDENCY, &val)) | |
251 | count += val; | |
252 | else | |
253 | skip_c7 = true; | |
254 | } | |
255 | ||
256 | return count; | |
257 | } | |
258 | ||
259 | static void noop_timer(unsigned long foo) | |
260 | { | |
261 | /* empty... just the fact that we get the interrupt wakes us up */ | |
262 | } | |
263 | ||
264 | static unsigned int get_compensation(int ratio) | |
265 | { | |
266 | unsigned int comp = 0; | |
267 | ||
268 | /* we only use compensation if all adjacent ones are good */ | |
269 | if (ratio == 1 && | |
270 | cal_data[ratio].confidence >= CONFIDENCE_OK && | |
271 | cal_data[ratio + 1].confidence >= CONFIDENCE_OK && | |
272 | cal_data[ratio + 2].confidence >= CONFIDENCE_OK) { | |
273 | comp = (cal_data[ratio].steady_comp + | |
274 | cal_data[ratio + 1].steady_comp + | |
275 | cal_data[ratio + 2].steady_comp) / 3; | |
276 | } else if (ratio == MAX_TARGET_RATIO - 1 && | |
277 | cal_data[ratio].confidence >= CONFIDENCE_OK && | |
278 | cal_data[ratio - 1].confidence >= CONFIDENCE_OK && | |
279 | cal_data[ratio - 2].confidence >= CONFIDENCE_OK) { | |
280 | comp = (cal_data[ratio].steady_comp + | |
281 | cal_data[ratio - 1].steady_comp + | |
282 | cal_data[ratio - 2].steady_comp) / 3; | |
283 | } else if (cal_data[ratio].confidence >= CONFIDENCE_OK && | |
284 | cal_data[ratio - 1].confidence >= CONFIDENCE_OK && | |
285 | cal_data[ratio + 1].confidence >= CONFIDENCE_OK) { | |
286 | comp = (cal_data[ratio].steady_comp + | |
287 | cal_data[ratio - 1].steady_comp + | |
288 | cal_data[ratio + 1].steady_comp) / 3; | |
289 | } | |
290 | ||
291 | /* REVISIT: simple penalty of double idle injection */ | |
292 | if (reduce_irq) | |
293 | comp = ratio; | |
294 | /* do not exceed limit */ | |
295 | if (comp + ratio >= MAX_TARGET_RATIO) | |
296 | comp = MAX_TARGET_RATIO - ratio - 1; | |
297 | ||
298 | return comp; | |
299 | } | |
300 | ||
301 | static void adjust_compensation(int target_ratio, unsigned int win) | |
302 | { | |
303 | int delta; | |
304 | struct powerclamp_calibration_data *d = &cal_data[target_ratio]; | |
305 | ||
306 | /* | |
307 | * adjust compensations if confidence level has not been reached or | |
308 | * there are too many wakeups during the last idle injection period, we | |
309 | * cannot trust the data for compensation. | |
310 | */ | |
311 | if (d->confidence >= CONFIDENCE_OK || | |
312 | atomic_read(&idle_wakeup_counter) > | |
313 | win * num_online_cpus()) | |
314 | return; | |
315 | ||
316 | delta = set_target_ratio - current_ratio; | |
317 | /* filter out bad data */ | |
318 | if (delta >= 0 && delta <= (1+target_ratio/10)) { | |
319 | if (d->steady_comp) | |
320 | d->steady_comp = | |
321 | roundup(delta+d->steady_comp, 2)/2; | |
322 | else | |
323 | d->steady_comp = delta; | |
324 | d->confidence++; | |
325 | } | |
326 | } | |
327 | ||
328 | static bool powerclamp_adjust_controls(unsigned int target_ratio, | |
329 | unsigned int guard, unsigned int win) | |
330 | { | |
331 | static u64 msr_last, tsc_last; | |
332 | u64 msr_now, tsc_now; | |
333 | u64 val64; | |
334 | ||
335 | /* check result for the last window */ | |
336 | msr_now = pkg_state_counter(); | |
337 | rdtscll(tsc_now); | |
338 | ||
339 | /* calculate pkg cstate vs tsc ratio */ | |
340 | if (!msr_last || !tsc_last) | |
341 | current_ratio = 1; | |
342 | else if (tsc_now-tsc_last) { | |
343 | val64 = 100*(msr_now-msr_last); | |
344 | do_div(val64, (tsc_now-tsc_last)); | |
345 | current_ratio = val64; | |
346 | } | |
347 | ||
348 | /* update record */ | |
349 | msr_last = msr_now; | |
350 | tsc_last = tsc_now; | |
351 | ||
352 | adjust_compensation(target_ratio, win); | |
353 | /* | |
354 | * too many external interrupts, set flag such | |
355 | * that we can take measure later. | |
356 | */ | |
357 | reduce_irq = atomic_read(&idle_wakeup_counter) >= | |
358 | 2 * win * num_online_cpus(); | |
359 | ||
360 | atomic_set(&idle_wakeup_counter, 0); | |
361 | /* if we are above target+guard, skip */ | |
362 | return set_target_ratio + guard <= current_ratio; | |
363 | } | |
364 | ||
365 | static int clamp_thread(void *arg) | |
366 | { | |
367 | int cpunr = (unsigned long)arg; | |
368 | DEFINE_TIMER(wakeup_timer, noop_timer, 0, 0); | |
369 | static const struct sched_param param = { | |
370 | .sched_priority = MAX_USER_RT_PRIO/2, | |
371 | }; | |
372 | unsigned int count = 0; | |
373 | unsigned int target_ratio; | |
374 | ||
375 | set_bit(cpunr, cpu_clamping_mask); | |
376 | set_freezable(); | |
377 | init_timer_on_stack(&wakeup_timer); | |
378 | sched_setscheduler(current, SCHED_FIFO, ¶m); | |
379 | ||
380 | while (true == clamping && !kthread_should_stop() && | |
381 | cpu_online(cpunr)) { | |
382 | int sleeptime; | |
383 | unsigned long target_jiffies; | |
384 | unsigned int guard; | |
385 | unsigned int compensation = 0; | |
386 | int interval; /* jiffies to sleep for each attempt */ | |
387 | unsigned int duration_jiffies = msecs_to_jiffies(duration); | |
388 | unsigned int window_size_now; | |
389 | ||
390 | try_to_freeze(); | |
391 | /* | |
392 | * make sure user selected ratio does not take effect until | |
393 | * the next round. adjust target_ratio if user has changed | |
394 | * target such that we can converge quickly. | |
395 | */ | |
396 | target_ratio = set_target_ratio; | |
397 | guard = 1 + target_ratio/20; | |
398 | window_size_now = window_size; | |
399 | count++; | |
400 | ||
401 | /* | |
402 | * systems may have different ability to enter package level | |
403 | * c-states, thus we need to compensate the injected idle ratio | |
404 | * to achieve the actual target reported by the HW. | |
405 | */ | |
406 | compensation = get_compensation(target_ratio); | |
407 | interval = duration_jiffies*100/(target_ratio+compensation); | |
408 | ||
409 | /* align idle time */ | |
410 | target_jiffies = roundup(jiffies, interval); | |
411 | sleeptime = target_jiffies - jiffies; | |
412 | if (sleeptime <= 0) | |
413 | sleeptime = 1; | |
414 | schedule_timeout_interruptible(sleeptime); | |
415 | /* | |
416 | * only elected controlling cpu can collect stats and update | |
417 | * control parameters. | |
418 | */ | |
419 | if (cpunr == control_cpu && !(count%window_size_now)) { | |
420 | should_skip = | |
421 | powerclamp_adjust_controls(target_ratio, | |
422 | guard, window_size_now); | |
423 | smp_mb(); | |
424 | } | |
425 | ||
426 | if (should_skip) | |
427 | continue; | |
428 | ||
429 | target_jiffies = jiffies + duration_jiffies; | |
430 | mod_timer(&wakeup_timer, target_jiffies); | |
431 | if (unlikely(local_softirq_pending())) | |
432 | continue; | |
433 | /* | |
434 | * stop tick sched during idle time, interrupts are still | |
435 | * allowed. thus jiffies are updated properly. | |
436 | */ | |
437 | preempt_disable(); | |
438 | tick_nohz_idle_enter(); | |
439 | /* mwait until target jiffies is reached */ | |
440 | while (time_before(jiffies, target_jiffies)) { | |
441 | unsigned long ecx = 1; | |
442 | unsigned long eax = target_mwait; | |
443 | ||
444 | /* | |
445 | * REVISIT: may call enter_idle() to notify drivers who | |
446 | * can save power during cpu idle. same for exit_idle() | |
447 | */ | |
448 | local_touch_nmi(); | |
449 | stop_critical_timings(); | |
16824255 | 450 | mwait_idle_with_hints(eax, ecx); |
d6d71ee4 JP |
451 | start_critical_timings(); |
452 | atomic_inc(&idle_wakeup_counter); | |
453 | } | |
454 | tick_nohz_idle_exit(); | |
130816ce | 455 | preempt_enable(); |
d6d71ee4 JP |
456 | } |
457 | del_timer_sync(&wakeup_timer); | |
458 | clear_bit(cpunr, cpu_clamping_mask); | |
459 | ||
460 | return 0; | |
461 | } | |
462 | ||
463 | /* | |
464 | * 1 HZ polling while clamping is active, useful for userspace | |
465 | * to monitor actual idle ratio. | |
466 | */ | |
467 | static void poll_pkg_cstate(struct work_struct *dummy); | |
468 | static DECLARE_DELAYED_WORK(poll_pkg_cstate_work, poll_pkg_cstate); | |
469 | static void poll_pkg_cstate(struct work_struct *dummy) | |
470 | { | |
471 | static u64 msr_last; | |
472 | static u64 tsc_last; | |
473 | static unsigned long jiffies_last; | |
474 | ||
475 | u64 msr_now; | |
476 | unsigned long jiffies_now; | |
477 | u64 tsc_now; | |
478 | u64 val64; | |
479 | ||
480 | msr_now = pkg_state_counter(); | |
481 | rdtscll(tsc_now); | |
482 | jiffies_now = jiffies; | |
483 | ||
484 | /* calculate pkg cstate vs tsc ratio */ | |
485 | if (!msr_last || !tsc_last) | |
486 | pkg_cstate_ratio_cur = 1; | |
487 | else { | |
488 | if (tsc_now - tsc_last) { | |
489 | val64 = 100 * (msr_now - msr_last); | |
490 | do_div(val64, (tsc_now - tsc_last)); | |
491 | pkg_cstate_ratio_cur = val64; | |
492 | } | |
493 | } | |
494 | ||
495 | /* update record */ | |
496 | msr_last = msr_now; | |
497 | jiffies_last = jiffies_now; | |
498 | tsc_last = tsc_now; | |
499 | ||
500 | if (true == clamping) | |
501 | schedule_delayed_work(&poll_pkg_cstate_work, HZ); | |
502 | } | |
503 | ||
504 | static int start_power_clamp(void) | |
505 | { | |
506 | unsigned long cpu; | |
507 | struct task_struct *thread; | |
508 | ||
509 | /* check if pkg cstate counter is completely 0, abort in this case */ | |
7734e3ac | 510 | if (!has_pkg_state_counter()) { |
d6d71ee4 JP |
511 | pr_err("pkg cstate counter not functional, abort\n"); |
512 | return -EINVAL; | |
513 | } | |
514 | ||
c8165dc0 | 515 | set_target_ratio = clamp(set_target_ratio, 0U, MAX_TARGET_RATIO - 1); |
d6d71ee4 JP |
516 | /* prevent cpu hotplug */ |
517 | get_online_cpus(); | |
518 | ||
519 | /* prefer BSP */ | |
520 | control_cpu = 0; | |
521 | if (!cpu_online(control_cpu)) | |
522 | control_cpu = smp_processor_id(); | |
523 | ||
524 | clamping = true; | |
525 | schedule_delayed_work(&poll_pkg_cstate_work, 0); | |
526 | ||
527 | /* start one thread per online cpu */ | |
528 | for_each_online_cpu(cpu) { | |
529 | struct task_struct **p = | |
530 | per_cpu_ptr(powerclamp_thread, cpu); | |
531 | ||
532 | thread = kthread_create_on_node(clamp_thread, | |
533 | (void *) cpu, | |
534 | cpu_to_node(cpu), | |
535 | "kidle_inject/%ld", cpu); | |
536 | /* bind to cpu here */ | |
537 | if (likely(!IS_ERR(thread))) { | |
538 | kthread_bind(thread, cpu); | |
539 | wake_up_process(thread); | |
540 | *p = thread; | |
541 | } | |
542 | ||
543 | } | |
544 | put_online_cpus(); | |
545 | ||
546 | return 0; | |
547 | } | |
548 | ||
549 | static void end_power_clamp(void) | |
550 | { | |
551 | int i; | |
552 | struct task_struct *thread; | |
553 | ||
554 | clamping = false; | |
555 | /* | |
556 | * make clamping visible to other cpus and give per cpu clamping threads | |
557 | * sometime to exit, or gets killed later. | |
558 | */ | |
559 | smp_mb(); | |
560 | msleep(20); | |
561 | if (bitmap_weight(cpu_clamping_mask, num_possible_cpus())) { | |
562 | for_each_set_bit(i, cpu_clamping_mask, num_possible_cpus()) { | |
563 | pr_debug("clamping thread for cpu %d alive, kill\n", i); | |
564 | thread = *per_cpu_ptr(powerclamp_thread, i); | |
565 | kthread_stop(thread); | |
566 | } | |
567 | } | |
568 | } | |
569 | ||
570 | static int powerclamp_cpu_callback(struct notifier_block *nfb, | |
571 | unsigned long action, void *hcpu) | |
572 | { | |
573 | unsigned long cpu = (unsigned long)hcpu; | |
574 | struct task_struct *thread; | |
575 | struct task_struct **percpu_thread = | |
576 | per_cpu_ptr(powerclamp_thread, cpu); | |
577 | ||
578 | if (false == clamping) | |
579 | goto exit_ok; | |
580 | ||
581 | switch (action) { | |
582 | case CPU_ONLINE: | |
583 | thread = kthread_create_on_node(clamp_thread, | |
584 | (void *) cpu, | |
585 | cpu_to_node(cpu), | |
586 | "kidle_inject/%lu", cpu); | |
587 | if (likely(!IS_ERR(thread))) { | |
588 | kthread_bind(thread, cpu); | |
589 | wake_up_process(thread); | |
590 | *percpu_thread = thread; | |
591 | } | |
592 | /* prefer BSP as controlling CPU */ | |
593 | if (cpu == 0) { | |
594 | control_cpu = 0; | |
595 | smp_mb(); | |
596 | } | |
597 | break; | |
598 | case CPU_DEAD: | |
599 | if (test_bit(cpu, cpu_clamping_mask)) { | |
600 | pr_err("cpu %lu dead but powerclamping thread is not\n", | |
601 | cpu); | |
602 | kthread_stop(*percpu_thread); | |
603 | } | |
604 | if (cpu == control_cpu) { | |
605 | control_cpu = smp_processor_id(); | |
606 | smp_mb(); | |
607 | } | |
608 | } | |
609 | ||
610 | exit_ok: | |
611 | return NOTIFY_OK; | |
612 | } | |
613 | ||
614 | static struct notifier_block powerclamp_cpu_notifier = { | |
615 | .notifier_call = powerclamp_cpu_callback, | |
616 | }; | |
617 | ||
618 | static int powerclamp_get_max_state(struct thermal_cooling_device *cdev, | |
619 | unsigned long *state) | |
620 | { | |
621 | *state = MAX_TARGET_RATIO; | |
622 | ||
623 | return 0; | |
624 | } | |
625 | ||
626 | static int powerclamp_get_cur_state(struct thermal_cooling_device *cdev, | |
627 | unsigned long *state) | |
628 | { | |
629 | if (true == clamping) | |
630 | *state = pkg_cstate_ratio_cur; | |
631 | else | |
632 | /* to save power, do not poll idle ratio while not clamping */ | |
633 | *state = -1; /* indicates invalid state */ | |
634 | ||
635 | return 0; | |
636 | } | |
637 | ||
638 | static int powerclamp_set_cur_state(struct thermal_cooling_device *cdev, | |
639 | unsigned long new_target_ratio) | |
640 | { | |
641 | int ret = 0; | |
642 | ||
643 | new_target_ratio = clamp(new_target_ratio, 0UL, | |
644 | (unsigned long) (MAX_TARGET_RATIO-1)); | |
645 | if (set_target_ratio == 0 && new_target_ratio > 0) { | |
646 | pr_info("Start idle injection to reduce power\n"); | |
647 | set_target_ratio = new_target_ratio; | |
648 | ret = start_power_clamp(); | |
649 | goto exit_set; | |
650 | } else if (set_target_ratio > 0 && new_target_ratio == 0) { | |
651 | pr_info("Stop forced idle injection\n"); | |
652 | set_target_ratio = 0; | |
653 | end_power_clamp(); | |
654 | } else /* adjust currently running */ { | |
655 | set_target_ratio = new_target_ratio; | |
656 | /* make new set_target_ratio visible to other cpus */ | |
657 | smp_mb(); | |
658 | } | |
659 | ||
660 | exit_set: | |
661 | return ret; | |
662 | } | |
663 | ||
664 | /* bind to generic thermal layer as cooling device*/ | |
665 | static struct thermal_cooling_device_ops powerclamp_cooling_ops = { | |
666 | .get_max_state = powerclamp_get_max_state, | |
667 | .get_cur_state = powerclamp_get_cur_state, | |
668 | .set_cur_state = powerclamp_set_cur_state, | |
669 | }; | |
670 | ||
671 | /* runs on Nehalem and later */ | |
672 | static const struct x86_cpu_id intel_powerclamp_ids[] = { | |
673 | { X86_VENDOR_INTEL, 6, 0x1a}, | |
674 | { X86_VENDOR_INTEL, 6, 0x1c}, | |
675 | { X86_VENDOR_INTEL, 6, 0x1e}, | |
676 | { X86_VENDOR_INTEL, 6, 0x1f}, | |
677 | { X86_VENDOR_INTEL, 6, 0x25}, | |
678 | { X86_VENDOR_INTEL, 6, 0x26}, | |
679 | { X86_VENDOR_INTEL, 6, 0x2a}, | |
680 | { X86_VENDOR_INTEL, 6, 0x2c}, | |
681 | { X86_VENDOR_INTEL, 6, 0x2d}, | |
682 | { X86_VENDOR_INTEL, 6, 0x2e}, | |
683 | { X86_VENDOR_INTEL, 6, 0x2f}, | |
9a17f56c | 684 | { X86_VENDOR_INTEL, 6, 0x37}, |
d6d71ee4 | 685 | { X86_VENDOR_INTEL, 6, 0x3a}, |
90fc9cd2 | 686 | { X86_VENDOR_INTEL, 6, 0x3c}, |
9a17f56c | 687 | { X86_VENDOR_INTEL, 6, 0x3d}, |
90fc9cd2 JP |
688 | { X86_VENDOR_INTEL, 6, 0x3e}, |
689 | { X86_VENDOR_INTEL, 6, 0x3f}, | |
690 | { X86_VENDOR_INTEL, 6, 0x45}, | |
691 | { X86_VENDOR_INTEL, 6, 0x46}, | |
d6d71ee4 JP |
692 | {} |
693 | }; | |
694 | MODULE_DEVICE_TABLE(x86cpu, intel_powerclamp_ids); | |
695 | ||
696 | static int powerclamp_probe(void) | |
697 | { | |
698 | if (!x86_match_cpu(intel_powerclamp_ids)) { | |
699 | pr_err("Intel powerclamp does not run on family %d model %d\n", | |
700 | boot_cpu_data.x86, boot_cpu_data.x86_model); | |
701 | return -ENODEV; | |
702 | } | |
703 | if (!boot_cpu_has(X86_FEATURE_NONSTOP_TSC) || | |
704 | !boot_cpu_has(X86_FEATURE_CONSTANT_TSC) || | |
705 | !boot_cpu_has(X86_FEATURE_MWAIT) || | |
706 | !boot_cpu_has(X86_FEATURE_ARAT)) | |
707 | return -ENODEV; | |
708 | ||
709 | /* find the deepest mwait value */ | |
710 | find_target_mwait(); | |
711 | ||
712 | return 0; | |
713 | } | |
714 | ||
715 | static int powerclamp_debug_show(struct seq_file *m, void *unused) | |
716 | { | |
717 | int i = 0; | |
718 | ||
719 | seq_printf(m, "controlling cpu: %d\n", control_cpu); | |
720 | seq_printf(m, "pct confidence steady dynamic (compensation)\n"); | |
721 | for (i = 0; i < MAX_TARGET_RATIO; i++) { | |
722 | seq_printf(m, "%d\t%lu\t%lu\t%lu\n", | |
723 | i, | |
724 | cal_data[i].confidence, | |
725 | cal_data[i].steady_comp, | |
726 | cal_data[i].dynamic_comp); | |
727 | } | |
728 | ||
729 | return 0; | |
730 | } | |
731 | ||
732 | static int powerclamp_debug_open(struct inode *inode, | |
733 | struct file *file) | |
734 | { | |
735 | return single_open(file, powerclamp_debug_show, inode->i_private); | |
736 | } | |
737 | ||
738 | static const struct file_operations powerclamp_debug_fops = { | |
739 | .open = powerclamp_debug_open, | |
740 | .read = seq_read, | |
741 | .llseek = seq_lseek, | |
742 | .release = single_release, | |
743 | .owner = THIS_MODULE, | |
744 | }; | |
745 | ||
746 | static inline void powerclamp_create_debug_files(void) | |
747 | { | |
748 | debug_dir = debugfs_create_dir("intel_powerclamp", NULL); | |
749 | if (!debug_dir) | |
750 | return; | |
751 | ||
752 | if (!debugfs_create_file("powerclamp_calib", S_IRUGO, debug_dir, | |
753 | cal_data, &powerclamp_debug_fops)) | |
754 | goto file_error; | |
755 | ||
756 | return; | |
757 | ||
758 | file_error: | |
759 | debugfs_remove_recursive(debug_dir); | |
760 | } | |
761 | ||
762 | static int powerclamp_init(void) | |
763 | { | |
764 | int retval; | |
765 | int bitmap_size; | |
766 | ||
767 | bitmap_size = BITS_TO_LONGS(num_possible_cpus()) * sizeof(long); | |
768 | cpu_clamping_mask = kzalloc(bitmap_size, GFP_KERNEL); | |
769 | if (!cpu_clamping_mask) | |
770 | return -ENOMEM; | |
771 | ||
772 | /* probe cpu features and ids here */ | |
773 | retval = powerclamp_probe(); | |
774 | if (retval) | |
c32a5087 | 775 | goto exit_free; |
776 | ||
d6d71ee4 JP |
777 | /* set default limit, maybe adjusted during runtime based on feedback */ |
778 | window_size = 2; | |
779 | register_hotcpu_notifier(&powerclamp_cpu_notifier); | |
c32a5087 | 780 | |
d6d71ee4 | 781 | powerclamp_thread = alloc_percpu(struct task_struct *); |
c32a5087 | 782 | if (!powerclamp_thread) { |
783 | retval = -ENOMEM; | |
784 | goto exit_unregister; | |
785 | } | |
786 | ||
d6d71ee4 JP |
787 | cooling_dev = thermal_cooling_device_register("intel_powerclamp", NULL, |
788 | &powerclamp_cooling_ops); | |
c32a5087 | 789 | if (IS_ERR(cooling_dev)) { |
790 | retval = -ENODEV; | |
791 | goto exit_free_thread; | |
792 | } | |
d6d71ee4 JP |
793 | |
794 | if (!duration) | |
795 | duration = jiffies_to_msecs(DEFAULT_DURATION_JIFFIES); | |
c32a5087 | 796 | |
d6d71ee4 JP |
797 | powerclamp_create_debug_files(); |
798 | ||
799 | return 0; | |
c32a5087 | 800 | |
801 | exit_free_thread: | |
802 | free_percpu(powerclamp_thread); | |
803 | exit_unregister: | |
804 | unregister_hotcpu_notifier(&powerclamp_cpu_notifier); | |
805 | exit_free: | |
806 | kfree(cpu_clamping_mask); | |
807 | return retval; | |
d6d71ee4 JP |
808 | } |
809 | module_init(powerclamp_init); | |
810 | ||
811 | static void powerclamp_exit(void) | |
812 | { | |
813 | unregister_hotcpu_notifier(&powerclamp_cpu_notifier); | |
814 | end_power_clamp(); | |
815 | free_percpu(powerclamp_thread); | |
816 | thermal_cooling_device_unregister(cooling_dev); | |
817 | kfree(cpu_clamping_mask); | |
818 | ||
819 | cancel_delayed_work_sync(&poll_pkg_cstate_work); | |
820 | debugfs_remove_recursive(debug_dir); | |
821 | } | |
822 | module_exit(powerclamp_exit); | |
823 | ||
824 | MODULE_LICENSE("GPL"); | |
825 | MODULE_AUTHOR("Arjan van de Ven <arjan@linux.intel.com>"); | |
826 | MODULE_AUTHOR("Jacob Pan <jacob.jun.pan@linux.intel.com>"); | |
827 | MODULE_DESCRIPTION("Package Level C-state Idle Injection for Intel CPUs"); |