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