--- /dev/null
+/*
+ * intel_powerclamp.c - package c-state idle injection
+ *
+ * Copyright (c) 2012, Intel Corporation.
+ *
+ * Authors:
+ * Arjan van de Ven <arjan@linux.intel.com>
+ * Jacob Pan <jacob.jun.pan@linux.intel.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ *
+ * TODO:
+ * 1. better handle wakeup from external interrupts, currently a fixed
+ * compensation is added to clamping duration when excessive amount
+ * of wakeups are observed during idle time. the reason is that in
+ * case of external interrupts without need for ack, clamping down
+ * cpu in non-irq context does not reduce irq. for majority of the
+ * cases, clamping down cpu does help reduce irq as well, we should
+ * be able to differenciate the two cases and give a quantitative
+ * solution for the irqs that we can control. perhaps based on
+ * get_cpu_iowait_time_us()
+ *
+ * 2. synchronization with other hw blocks
+ *
+ *
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/delay.h>
+#include <linux/kthread.h>
+#include <linux/freezer.h>
+#include <linux/cpu.h>
+#include <linux/thermal.h>
+#include <linux/slab.h>
+#include <linux/tick.h>
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
+#include <linux/sched/rt.h>
+
+#include <asm/nmi.h>
+#include <asm/msr.h>
+#include <asm/mwait.h>
+#include <asm/cpu_device_id.h>
+#include <asm/idle.h>
+#include <asm/hardirq.h>
+
+#define MAX_TARGET_RATIO (50U)
+/* For each undisturbed clamping period (no extra wake ups during idle time),
+ * we increment the confidence counter for the given target ratio.
+ * CONFIDENCE_OK defines the level where runtime calibration results are
+ * valid.
+ */
+#define CONFIDENCE_OK (3)
+/* Default idle injection duration, driver adjust sleep time to meet target
+ * idle ratio. Similar to frequency modulation.
+ */
+#define DEFAULT_DURATION_JIFFIES (6)
+
+static unsigned int target_mwait;
+static struct dentry *debug_dir;
+
+/* user selected target */
+static unsigned int set_target_ratio;
+static unsigned int current_ratio;
+static bool should_skip;
+static bool reduce_irq;
+static atomic_t idle_wakeup_counter;
+static unsigned int control_cpu; /* The cpu assigned to collect stat and update
+ * control parameters. default to BSP but BSP
+ * can be offlined.
+ */
+static bool clamping;
+
+
+static struct task_struct * __percpu *powerclamp_thread;
+static struct thermal_cooling_device *cooling_dev;
+static unsigned long *cpu_clamping_mask; /* bit map for tracking per cpu
+ * clamping thread
+ */
+
+static unsigned int duration;
+static unsigned int pkg_cstate_ratio_cur;
+static unsigned int window_size;
+
+static int duration_set(const char *arg, const struct kernel_param *kp)
+{
+ int ret = 0;
+ unsigned long new_duration;
+
+ ret = kstrtoul(arg, 10, &new_duration);
+ if (ret)
+ goto exit;
+ if (new_duration > 25 || new_duration < 6) {
+ pr_err("Out of recommended range %lu, between 6-25ms\n",
+ new_duration);
+ ret = -EINVAL;
+ }
+
+ duration = clamp(new_duration, 6ul, 25ul);
+ smp_mb();
+
+exit:
+
+ return ret;
+}
+
+static struct kernel_param_ops duration_ops = {
+ .set = duration_set,
+ .get = param_get_int,
+};
+
+
+module_param_cb(duration, &duration_ops, &duration, 0644);
+MODULE_PARM_DESC(duration, "forced idle time for each attempt in msec.");
+
+struct powerclamp_calibration_data {
+ unsigned long confidence; /* used for calibration, basically a counter
+ * gets incremented each time a clamping
+ * period is completed without extra wakeups
+ * once that counter is reached given level,
+ * compensation is deemed usable.
+ */
+ unsigned long steady_comp; /* steady state compensation used when
+ * no extra wakeups occurred.
+ */
+ unsigned long dynamic_comp; /* compensate excessive wakeup from idle
+ * mostly from external interrupts.
+ */
+};
+
+static struct powerclamp_calibration_data cal_data[MAX_TARGET_RATIO];
+
+static int window_size_set(const char *arg, const struct kernel_param *kp)
+{
+ int ret = 0;
+ unsigned long new_window_size;
+
+ ret = kstrtoul(arg, 10, &new_window_size);
+ if (ret)
+ goto exit_win;
+ if (new_window_size > 10 || new_window_size < 2) {
+ pr_err("Out of recommended window size %lu, between 2-10\n",
+ new_window_size);
+ ret = -EINVAL;
+ }
+
+ window_size = clamp(new_window_size, 2ul, 10ul);
+ smp_mb();
+
+exit_win:
+
+ return ret;
+}
+
+static struct kernel_param_ops window_size_ops = {
+ .set = window_size_set,
+ .get = param_get_int,
+};
+
+module_param_cb(window_size, &window_size_ops, &window_size, 0644);
+MODULE_PARM_DESC(window_size, "sliding window in number of clamping cycles\n"
+ "\tpowerclamp controls idle ratio within this window. larger\n"
+ "\twindow size results in slower response time but more smooth\n"
+ "\tclamping results. default to 2.");
+
+static void find_target_mwait(void)
+{
+ unsigned int eax, ebx, ecx, edx;
+ unsigned int highest_cstate = 0;
+ unsigned int highest_subcstate = 0;
+ int i;
+
+ if (boot_cpu_data.cpuid_level < CPUID_MWAIT_LEAF)
+ return;
+
+ cpuid(CPUID_MWAIT_LEAF, &eax, &ebx, &ecx, &edx);
+
+ if (!(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED) ||
+ !(ecx & CPUID5_ECX_INTERRUPT_BREAK))
+ return;
+
+ edx >>= MWAIT_SUBSTATE_SIZE;
+ for (i = 0; i < 7 && edx; i++, edx >>= MWAIT_SUBSTATE_SIZE) {
+ if (edx & MWAIT_SUBSTATE_MASK) {
+ highest_cstate = i;
+ highest_subcstate = edx & MWAIT_SUBSTATE_MASK;
+ }
+ }
+ target_mwait = (highest_cstate << MWAIT_SUBSTATE_SIZE) |
+ (highest_subcstate - 1);
+
+}
+
+struct pkg_cstate_info {
+ bool skip;
+ int msr_index;
+ int cstate_id;
+};
+
+#define PKG_CSTATE_INIT(id) { \
+ .msr_index = MSR_PKG_C##id##_RESIDENCY, \
+ .cstate_id = id \
+ }
+
+static struct pkg_cstate_info pkg_cstates[] = {
+ PKG_CSTATE_INIT(2),
+ PKG_CSTATE_INIT(3),
+ PKG_CSTATE_INIT(6),
+ PKG_CSTATE_INIT(7),
+ PKG_CSTATE_INIT(8),
+ PKG_CSTATE_INIT(9),
+ PKG_CSTATE_INIT(10),
+ {NULL},
+};
+
+static bool has_pkg_state_counter(void)
+{
+ u64 val;
+ struct pkg_cstate_info *info = pkg_cstates;
+
+ /* check if any one of the counter msrs exists */
+ while (info->msr_index) {
+ if (!rdmsrl_safe(info->msr_index, &val))
+ return true;
+ info++;
+ }
+
+ return false;
+}
+
+static u64 pkg_state_counter(void)
+{
+ u64 val;
+ u64 count = 0;
+ struct pkg_cstate_info *info = pkg_cstates;
+
+ while (info->msr_index) {
+ if (!info->skip) {
+ if (!rdmsrl_safe(info->msr_index, &val))
+ count += val;
+ else
+ info->skip = true;
+ }
+ info++;
+ }
+
+ return count;
+}
+
+static void noop_timer(unsigned long foo)
+{
+ /* empty... just the fact that we get the interrupt wakes us up */
+}
+
+static unsigned int get_compensation(int ratio)
+{
+ unsigned int comp = 0;
+
+ /* we only use compensation if all adjacent ones are good */
+ if (ratio == 1 &&
+ cal_data[ratio].confidence >= CONFIDENCE_OK &&
+ cal_data[ratio + 1].confidence >= CONFIDENCE_OK &&
+ cal_data[ratio + 2].confidence >= CONFIDENCE_OK) {
+ comp = (cal_data[ratio].steady_comp +
+ cal_data[ratio + 1].steady_comp +
+ cal_data[ratio + 2].steady_comp) / 3;
+ } else if (ratio == MAX_TARGET_RATIO - 1 &&
+ cal_data[ratio].confidence >= CONFIDENCE_OK &&
+ cal_data[ratio - 1].confidence >= CONFIDENCE_OK &&
+ cal_data[ratio - 2].confidence >= CONFIDENCE_OK) {
+ comp = (cal_data[ratio].steady_comp +
+ cal_data[ratio - 1].steady_comp +
+ cal_data[ratio - 2].steady_comp) / 3;
+ } else if (cal_data[ratio].confidence >= CONFIDENCE_OK &&
+ cal_data[ratio - 1].confidence >= CONFIDENCE_OK &&
+ cal_data[ratio + 1].confidence >= CONFIDENCE_OK) {
+ comp = (cal_data[ratio].steady_comp +
+ cal_data[ratio - 1].steady_comp +
+ cal_data[ratio + 1].steady_comp) / 3;
+ }
+
+ /* REVISIT: simple penalty of double idle injection */
+ if (reduce_irq)
+ comp = ratio;
+ /* do not exceed limit */
+ if (comp + ratio >= MAX_TARGET_RATIO)
+ comp = MAX_TARGET_RATIO - ratio - 1;
+
+ return comp;
+}
+
+static void adjust_compensation(int target_ratio, unsigned int win)
+{
+ int delta;
+ struct powerclamp_calibration_data *d = &cal_data[target_ratio];
+
+ /*
+ * adjust compensations if confidence level has not been reached or
+ * there are too many wakeups during the last idle injection period, we
+ * cannot trust the data for compensation.
+ */
+ if (d->confidence >= CONFIDENCE_OK ||
+ atomic_read(&idle_wakeup_counter) >
+ win * num_online_cpus())
+ return;
+
+ delta = set_target_ratio - current_ratio;
+ /* filter out bad data */
+ if (delta >= 0 && delta <= (1+target_ratio/10)) {
+ if (d->steady_comp)
+ d->steady_comp =
+ roundup(delta+d->steady_comp, 2)/2;
+ else
+ d->steady_comp = delta;
+ d->confidence++;
+ }
+}
+
+static bool powerclamp_adjust_controls(unsigned int target_ratio,
+ unsigned int guard, unsigned int win)
+{
+ static u64 msr_last, tsc_last;
+ u64 msr_now, tsc_now;
+ u64 val64;
+
+ /* check result for the last window */
+ msr_now = pkg_state_counter();
+ rdtscll(tsc_now);
+
+ /* calculate pkg cstate vs tsc ratio */
+ if (!msr_last || !tsc_last)
+ current_ratio = 1;
+ else if (tsc_now-tsc_last) {
+ val64 = 100*(msr_now-msr_last);
+ do_div(val64, (tsc_now-tsc_last));
+ current_ratio = val64;
+ }
+
+ /* update record */
+ msr_last = msr_now;
+ tsc_last = tsc_now;
+
+ adjust_compensation(target_ratio, win);
+ /*
+ * too many external interrupts, set flag such
+ * that we can take measure later.
+ */
+ reduce_irq = atomic_read(&idle_wakeup_counter) >=
+ 2 * win * num_online_cpus();
+
+ atomic_set(&idle_wakeup_counter, 0);
+ /* if we are above target+guard, skip */
+ return set_target_ratio + guard <= current_ratio;
+}
+
+static int clamp_thread(void *arg)
+{
+ int cpunr = (unsigned long)arg;
+ DEFINE_TIMER(wakeup_timer, noop_timer, 0, 0);
+ static const struct sched_param param = {
+ .sched_priority = MAX_USER_RT_PRIO/2,
+ };
+ unsigned int count = 0;
+ unsigned int target_ratio;
+
+ set_bit(cpunr, cpu_clamping_mask);
+ set_freezable();
+ init_timer_on_stack(&wakeup_timer);
+ sched_setscheduler(current, SCHED_FIFO, ¶m);
+
+ while (true == clamping && !kthread_should_stop() &&
+ cpu_online(cpunr)) {
+ int sleeptime;
+ unsigned long target_jiffies;
+ unsigned int guard;
+ unsigned int compensation = 0;
+ int interval; /* jiffies to sleep for each attempt */
+ unsigned int duration_jiffies = msecs_to_jiffies(duration);
+ unsigned int window_size_now;
+
+ try_to_freeze();
+ /*
+ * make sure user selected ratio does not take effect until
+ * the next round. adjust target_ratio if user has changed
+ * target such that we can converge quickly.
+ */
+ target_ratio = set_target_ratio;
+ guard = 1 + target_ratio/20;
+ window_size_now = window_size;
+ count++;
+
+ /*
+ * systems may have different ability to enter package level
+ * c-states, thus we need to compensate the injected idle ratio
+ * to achieve the actual target reported by the HW.
+ */
+ compensation = get_compensation(target_ratio);
+ interval = duration_jiffies*100/(target_ratio+compensation);
+
+ /* align idle time */
+ target_jiffies = roundup(jiffies, interval);
+ sleeptime = target_jiffies - jiffies;
+ if (sleeptime <= 0)
+ sleeptime = 1;
+ schedule_timeout_interruptible(sleeptime);
+ /*
+ * only elected controlling cpu can collect stats and update
+ * control parameters.
+ */
+ if (cpunr == control_cpu && !(count%window_size_now)) {
+ should_skip =
+ powerclamp_adjust_controls(target_ratio,
+ guard, window_size_now);
+ smp_mb();
+ }
+
+ if (should_skip)
+ continue;
+
+ target_jiffies = jiffies + duration_jiffies;
+ mod_timer(&wakeup_timer, target_jiffies);
+ if (unlikely(local_softirq_pending()))
+ continue;
+ /*
+ * stop tick sched during idle time, interrupts are still
+ * allowed. thus jiffies are updated properly.
+ */
+ preempt_disable();
+ /* mwait until target jiffies is reached */
+ while (time_before(jiffies, target_jiffies)) {
+ unsigned long ecx = 1;
+ unsigned long eax = target_mwait;
+
+ /*
+ * REVISIT: may call enter_idle() to notify drivers who
+ * can save power during cpu idle. same for exit_idle()
+ */
+ local_touch_nmi();
+ stop_critical_timings();
+ mwait_idle_with_hints(eax, ecx);
+ start_critical_timings();
+ atomic_inc(&idle_wakeup_counter);
+ }
+ preempt_enable();
+ }
+ del_timer_sync(&wakeup_timer);
+ clear_bit(cpunr, cpu_clamping_mask);
+
+ return 0;
+}
+
+/*
+ * 1 HZ polling while clamping is active, useful for userspace
+ * to monitor actual idle ratio.
+ */
+static void poll_pkg_cstate(struct work_struct *dummy);
+static DECLARE_DELAYED_WORK(poll_pkg_cstate_work, poll_pkg_cstate);
+static void poll_pkg_cstate(struct work_struct *dummy)
+{
+ static u64 msr_last;
+ static u64 tsc_last;
+ static unsigned long jiffies_last;
+
+ u64 msr_now;
+ unsigned long jiffies_now;
+ u64 tsc_now;
+ u64 val64;
+
+ msr_now = pkg_state_counter();
+ rdtscll(tsc_now);
+ jiffies_now = jiffies;
+
+ /* calculate pkg cstate vs tsc ratio */
+ if (!msr_last || !tsc_last)
+ pkg_cstate_ratio_cur = 1;
+ else {
+ if (tsc_now - tsc_last) {
+ val64 = 100 * (msr_now - msr_last);
+ do_div(val64, (tsc_now - tsc_last));
+ pkg_cstate_ratio_cur = val64;
+ }
+ }
+
+ /* update record */
+ msr_last = msr_now;
+ jiffies_last = jiffies_now;
+ tsc_last = tsc_now;
+
+ if (true == clamping)
+ schedule_delayed_work(&poll_pkg_cstate_work, HZ);
+}
+
+static int start_power_clamp(void)
+{
+ unsigned long cpu;
+ struct task_struct *thread;
+
+ /* check if pkg cstate counter is completely 0, abort in this case */
+ if (!has_pkg_state_counter()) {
+ pr_err("pkg cstate counter not functional, abort\n");
+ return -EINVAL;
+ }
+
+ set_target_ratio = clamp(set_target_ratio, 0U, MAX_TARGET_RATIO - 1);
+ /* prevent cpu hotplug */
+ get_online_cpus();
+
+ /* prefer BSP */
+ control_cpu = 0;
+ if (!cpu_online(control_cpu))
+ control_cpu = smp_processor_id();
+
+ clamping = true;
+ schedule_delayed_work(&poll_pkg_cstate_work, 0);
+
+ /* start one thread per online cpu */
+ for_each_online_cpu(cpu) {
+ struct task_struct **p =
+ per_cpu_ptr(powerclamp_thread, cpu);
+
+ thread = kthread_create_on_node(clamp_thread,
+ (void *) cpu,
+ cpu_to_node(cpu),
+ "kidle_inject/%ld", cpu);
+ /* bind to cpu here */
+ if (likely(!IS_ERR(thread))) {
+ kthread_bind(thread, cpu);
+ wake_up_process(thread);
+ *p = thread;
+ }
+
+ }
+ put_online_cpus();
+
+ return 0;
+}
+
+static void end_power_clamp(void)
+{
+ int i;
+ struct task_struct *thread;
+
+ clamping = false;
+ /*
+ * make clamping visible to other cpus and give per cpu clamping threads
+ * sometime to exit, or gets killed later.
+ */
+ smp_mb();
+ msleep(20);
+ if (bitmap_weight(cpu_clamping_mask, num_possible_cpus())) {
+ for_each_set_bit(i, cpu_clamping_mask, num_possible_cpus()) {
+ pr_debug("clamping thread for cpu %d alive, kill\n", i);
+ thread = *per_cpu_ptr(powerclamp_thread, i);
+ kthread_stop(thread);
+ }
+ }
+}
+
+static int powerclamp_cpu_callback(struct notifier_block *nfb,
+ unsigned long action, void *hcpu)
+{
+ unsigned long cpu = (unsigned long)hcpu;
+ struct task_struct *thread;
+ struct task_struct **percpu_thread =
+ per_cpu_ptr(powerclamp_thread, cpu);
+
+ if (false == clamping)
+ goto exit_ok;
+
+ switch (action) {
+ case CPU_ONLINE:
+ thread = kthread_create_on_node(clamp_thread,
+ (void *) cpu,
+ cpu_to_node(cpu),
+ "kidle_inject/%lu", cpu);
+ if (likely(!IS_ERR(thread))) {
+ kthread_bind(thread, cpu);
+ wake_up_process(thread);
+ *percpu_thread = thread;
+ }
+ /* prefer BSP as controlling CPU */
+ if (cpu == 0) {
+ control_cpu = 0;
+ smp_mb();
+ }
+ break;
+ case CPU_DEAD:
+ if (test_bit(cpu, cpu_clamping_mask)) {
+ pr_err("cpu %lu dead but powerclamping thread is not\n",
+ cpu);
+ kthread_stop(*percpu_thread);
+ }
+ if (cpu == control_cpu) {
+ control_cpu = smp_processor_id();
+ smp_mb();
+ }
+ }
+
+exit_ok:
+ return NOTIFY_OK;
+}
+
+static struct notifier_block powerclamp_cpu_notifier = {
+ .notifier_call = powerclamp_cpu_callback,
+};
+
+static int powerclamp_get_max_state(struct thermal_cooling_device *cdev,
+ unsigned long *state)
+{
+ *state = MAX_TARGET_RATIO;
+
+ return 0;
+}
+
+static int powerclamp_get_cur_state(struct thermal_cooling_device *cdev,
+ unsigned long *state)
+{
+ if (true == clamping)
+ *state = pkg_cstate_ratio_cur;
+ else
+ /* to save power, do not poll idle ratio while not clamping */
+ *state = -1; /* indicates invalid state */
+
+ return 0;
+}
+
+static int powerclamp_set_cur_state(struct thermal_cooling_device *cdev,
+ unsigned long new_target_ratio)
+{
+ int ret = 0;
+
+ new_target_ratio = clamp(new_target_ratio, 0UL,
+ (unsigned long) (MAX_TARGET_RATIO-1));
+ if (set_target_ratio == 0 && new_target_ratio > 0) {
+ pr_info("Start idle injection to reduce power\n");
+ set_target_ratio = new_target_ratio;
+ ret = start_power_clamp();
+ goto exit_set;
+ } else if (set_target_ratio > 0 && new_target_ratio == 0) {
+ pr_info("Stop forced idle injection\n");
+ set_target_ratio = 0;
+ end_power_clamp();
+ } else /* adjust currently running */ {
+ set_target_ratio = new_target_ratio;
+ /* make new set_target_ratio visible to other cpus */
+ smp_mb();
+ }
+
+exit_set:
+ return ret;
+}
+
+/* bind to generic thermal layer as cooling device*/
+static struct thermal_cooling_device_ops powerclamp_cooling_ops = {
+ .get_max_state = powerclamp_get_max_state,
+ .get_cur_state = powerclamp_get_cur_state,
+ .set_cur_state = powerclamp_set_cur_state,
+};
+
+/* runs on Nehalem and later */
+static const struct x86_cpu_id intel_powerclamp_ids[] __initconst = {
+ { X86_VENDOR_INTEL, 6, 0x1a},
+ { X86_VENDOR_INTEL, 6, 0x1c},
+ { X86_VENDOR_INTEL, 6, 0x1e},
+ { X86_VENDOR_INTEL, 6, 0x1f},
+ { X86_VENDOR_INTEL, 6, 0x25},
+ { X86_VENDOR_INTEL, 6, 0x26},
+ { X86_VENDOR_INTEL, 6, 0x2a},
+ { X86_VENDOR_INTEL, 6, 0x2c},
+ { X86_VENDOR_INTEL, 6, 0x2d},
+ { X86_VENDOR_INTEL, 6, 0x2e},
+ { X86_VENDOR_INTEL, 6, 0x2f},
+ { X86_VENDOR_INTEL, 6, 0x37},
+ { X86_VENDOR_INTEL, 6, 0x3a},
+ { X86_VENDOR_INTEL, 6, 0x3c},
+ { X86_VENDOR_INTEL, 6, 0x3d},
+ { X86_VENDOR_INTEL, 6, 0x3e},
+ { X86_VENDOR_INTEL, 6, 0x3f},
+ { X86_VENDOR_INTEL, 6, 0x45},
+ { X86_VENDOR_INTEL, 6, 0x46},
+ { X86_VENDOR_INTEL, 6, 0x4c},
+ { X86_VENDOR_INTEL, 6, 0x4d},
+ { X86_VENDOR_INTEL, 6, 0x4f},
+ { X86_VENDOR_INTEL, 6, 0x56},
+ {}
+};
+MODULE_DEVICE_TABLE(x86cpu, intel_powerclamp_ids);
+
+static int __init powerclamp_probe(void)
+{
+ if (!x86_match_cpu(intel_powerclamp_ids)) {
+ pr_err("Intel powerclamp does not run on family %d model %d\n",
+ boot_cpu_data.x86, boot_cpu_data.x86_model);
+ return -ENODEV;
+ }
+ if (!boot_cpu_has(X86_FEATURE_NONSTOP_TSC) ||
+ !boot_cpu_has(X86_FEATURE_CONSTANT_TSC) ||
+ !boot_cpu_has(X86_FEATURE_MWAIT) ||
+ !boot_cpu_has(X86_FEATURE_ARAT))
+ return -ENODEV;
+
+ /* find the deepest mwait value */
+ find_target_mwait();
+
+ return 0;
+}
+
+static int powerclamp_debug_show(struct seq_file *m, void *unused)
+{
+ int i = 0;
+
+ seq_printf(m, "controlling cpu: %d\n", control_cpu);
+ seq_printf(m, "pct confidence steady dynamic (compensation)\n");
+ for (i = 0; i < MAX_TARGET_RATIO; i++) {
+ seq_printf(m, "%d\t%lu\t%lu\t%lu\n",
+ i,
+ cal_data[i].confidence,
+ cal_data[i].steady_comp,
+ cal_data[i].dynamic_comp);
+ }
+
+ return 0;
+}
+
+static int powerclamp_debug_open(struct inode *inode,
+ struct file *file)
+{
+ return single_open(file, powerclamp_debug_show, inode->i_private);
+}
+
+static const struct file_operations powerclamp_debug_fops = {
+ .open = powerclamp_debug_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = single_release,
+ .owner = THIS_MODULE,
+};
+
+static inline void powerclamp_create_debug_files(void)
+{
+ debug_dir = debugfs_create_dir("intel_powerclamp", NULL);
+ if (!debug_dir)
+ return;
+
+ if (!debugfs_create_file("powerclamp_calib", S_IRUGO, debug_dir,
+ cal_data, &powerclamp_debug_fops))
+ goto file_error;
+
+ return;
+
+file_error:
+ debugfs_remove_recursive(debug_dir);
+}
+
+static int __init powerclamp_init(void)
+{
+ int retval;
+ int bitmap_size;
+
+ bitmap_size = BITS_TO_LONGS(num_possible_cpus()) * sizeof(long);
+ cpu_clamping_mask = kzalloc(bitmap_size, GFP_KERNEL);
+ if (!cpu_clamping_mask)
+ return -ENOMEM;
+
+ /* probe cpu features and ids here */
+ retval = powerclamp_probe();
+ if (retval)
+ goto exit_free;
+
+ /* set default limit, maybe adjusted during runtime based on feedback */
+ window_size = 2;
+ register_hotcpu_notifier(&powerclamp_cpu_notifier);
+
+ powerclamp_thread = alloc_percpu(struct task_struct *);
+ if (!powerclamp_thread) {
+ retval = -ENOMEM;
+ goto exit_unregister;
+ }
+
+ cooling_dev = thermal_cooling_device_register("intel_powerclamp", NULL,
+ &powerclamp_cooling_ops);
+ if (IS_ERR(cooling_dev)) {
+ retval = -ENODEV;
+ goto exit_free_thread;
+ }
+
+ if (!duration)
+ duration = jiffies_to_msecs(DEFAULT_DURATION_JIFFIES);
+
+ powerclamp_create_debug_files();
+
+ return 0;
+
+exit_free_thread:
+ free_percpu(powerclamp_thread);
+exit_unregister:
+ unregister_hotcpu_notifier(&powerclamp_cpu_notifier);
+exit_free:
+ kfree(cpu_clamping_mask);
+ return retval;
+}
+module_init(powerclamp_init);
+
+static void __exit powerclamp_exit(void)
+{
+ unregister_hotcpu_notifier(&powerclamp_cpu_notifier);
+ end_power_clamp();
+ free_percpu(powerclamp_thread);
+ thermal_cooling_device_unregister(cooling_dev);
+ kfree(cpu_clamping_mask);
+
+ cancel_delayed_work_sync(&poll_pkg_cstate_work);
+ debugfs_remove_recursive(debug_dir);
+}
+module_exit(powerclamp_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Arjan van de Ven <arjan@linux.intel.com>");
+MODULE_AUTHOR("Jacob Pan <jacob.jun.pan@linux.intel.com>");
+MODULE_DESCRIPTION("Package Level C-state Idle Injection for Intel CPUs");
Code Review / kvmfornfv.git / blobdiff