diff options
Diffstat (limited to 'drivers/thermal/intel/intel_powerclamp.c')
| -rw-r--r-- | drivers/thermal/intel/intel_powerclamp.c | 849 |
1 files changed, 849 insertions, 0 deletions
diff --git a/drivers/thermal/intel/intel_powerclamp.c b/drivers/thermal/intel/intel_powerclamp.c new file mode 100644 index 0000000000..5ac5cb60ba --- /dev/null +++ b/drivers/thermal/intel/intel_powerclamp.c @@ -0,0 +1,849 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * intel_powerclamp.c - package c-state idle injection + * + * Copyright (c) 2012-2023, Intel Corporation. + * + * Authors: + * Arjan van de Ven <arjan@linux.intel.com> + * Jacob Pan <jacob.jun.pan@linux.intel.com> + * + * 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 differentiate 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/cpu.h> +#include <linux/thermal.h> +#include <linux/debugfs.h> +#include <linux/seq_file.h> +#include <linux/idle_inject.h> + +#include <asm/msr.h> +#include <asm/mwait.h> +#include <asm/cpu_device_id.h> + +#define MAX_TARGET_RATIO (100U) +/* 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; +static bool poll_pkg_cstate_enable; + +/* Idle ratio observed using package C-state counters */ +static unsigned int current_ratio; + +/* Skip the idle injection till set to true */ +static bool should_skip; + +struct powerclamp_data { + unsigned int cpu; + unsigned int count; + unsigned int guard; + unsigned int window_size_now; + unsigned int target_ratio; + bool clamping; +}; + +static struct powerclamp_data powerclamp_data; + +static struct thermal_cooling_device *cooling_dev; + +static DEFINE_MUTEX(powerclamp_lock); + +/* This duration is in microseconds */ +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; + goto exit; + } + + mutex_lock(&powerclamp_lock); + duration = clamp(new_duration, 6ul, 25ul) * 1000; + mutex_unlock(&powerclamp_lock); +exit: + + return ret; +} + +static int duration_get(char *buf, const struct kernel_param *kp) +{ + int ret; + + mutex_lock(&powerclamp_lock); + ret = sysfs_emit(buf, "%d\n", duration / 1000); + mutex_unlock(&powerclamp_lock); + + return ret; +} + +static const struct kernel_param_ops duration_ops = { + .set = duration_set, + .get = duration_get, +}; + +module_param_cb(duration, &duration_ops, NULL, 0644); +MODULE_PARM_DESC(duration, "forced idle time for each attempt in msec."); + +#define DEFAULT_MAX_IDLE 50 +#define MAX_ALL_CPU_IDLE 75 + +static u8 max_idle = DEFAULT_MAX_IDLE; + +static cpumask_var_t idle_injection_cpu_mask; + +static int allocate_copy_idle_injection_mask(const struct cpumask *copy_mask) +{ + if (cpumask_available(idle_injection_cpu_mask)) + goto copy_mask; + + /* This mask is allocated only one time and freed during module exit */ + if (!alloc_cpumask_var(&idle_injection_cpu_mask, GFP_KERNEL)) + return -ENOMEM; + +copy_mask: + cpumask_copy(idle_injection_cpu_mask, copy_mask); + + return 0; +} + +/* Return true if the cpumask and idle percent combination is invalid */ +static bool check_invalid(cpumask_var_t mask, u8 idle) +{ + if (cpumask_equal(cpu_present_mask, mask) && idle > MAX_ALL_CPU_IDLE) + return true; + + return false; +} + +static int cpumask_set(const char *arg, const struct kernel_param *kp) +{ + cpumask_var_t new_mask; + int ret; + + mutex_lock(&powerclamp_lock); + + /* Can't set mask when cooling device is in use */ + if (powerclamp_data.clamping) { + ret = -EAGAIN; + goto skip_cpumask_set; + } + + ret = alloc_cpumask_var(&new_mask, GFP_KERNEL); + if (!ret) + goto skip_cpumask_set; + + ret = bitmap_parse(arg, strlen(arg), cpumask_bits(new_mask), + nr_cpumask_bits); + if (ret) + goto free_cpumask_set; + + if (cpumask_empty(new_mask) || check_invalid(new_mask, max_idle)) { + ret = -EINVAL; + goto free_cpumask_set; + } + + /* + * When module parameters are passed from kernel command line + * during insmod, the module parameter callback is called + * before powerclamp_init(), so we can't assume that some + * cpumask can be allocated and copied before here. Also + * in this case this cpumask is used as the default mask. + */ + ret = allocate_copy_idle_injection_mask(new_mask); + +free_cpumask_set: + free_cpumask_var(new_mask); +skip_cpumask_set: + mutex_unlock(&powerclamp_lock); + + return ret; +} + +static int cpumask_get(char *buf, const struct kernel_param *kp) +{ + if (!cpumask_available(idle_injection_cpu_mask)) + return -ENODEV; + + return bitmap_print_to_pagebuf(false, buf, cpumask_bits(idle_injection_cpu_mask), + nr_cpumask_bits); +} + +static const struct kernel_param_ops cpumask_ops = { + .set = cpumask_set, + .get = cpumask_get, +}; + +module_param_cb(cpumask, &cpumask_ops, NULL, 0644); +MODULE_PARM_DESC(cpumask, "Mask of CPUs to use for idle injection."); + +static int max_idle_set(const char *arg, const struct kernel_param *kp) +{ + u8 new_max_idle; + int ret = 0; + + mutex_lock(&powerclamp_lock); + + /* Can't set mask when cooling device is in use */ + if (powerclamp_data.clamping) { + ret = -EAGAIN; + goto skip_limit_set; + } + + ret = kstrtou8(arg, 10, &new_max_idle); + if (ret) + goto skip_limit_set; + + if (new_max_idle > MAX_TARGET_RATIO) { + ret = -EINVAL; + goto skip_limit_set; + } + + if (!cpumask_available(idle_injection_cpu_mask)) { + ret = allocate_copy_idle_injection_mask(cpu_present_mask); + if (ret) + goto skip_limit_set; + } + + if (check_invalid(idle_injection_cpu_mask, new_max_idle)) { + ret = -EINVAL; + goto skip_limit_set; + } + + max_idle = new_max_idle; + +skip_limit_set: + mutex_unlock(&powerclamp_lock); + + return ret; +} + +static const struct kernel_param_ops max_idle_ops = { + .set = max_idle_set, + .get = param_get_byte, +}; + +module_param_cb(max_idle, &max_idle_ops, &max_idle, 0644); +MODULE_PARM_DESC(max_idle, "maximum injected idle time to the total CPU time ratio in percent range:1-100"); + +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 const 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 unsigned int get_compensation(int ratio) +{ + unsigned int comp = 0; + + if (!poll_pkg_cstate_enable) + return 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; + } + + /* 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. + */ + if (d->confidence >= CONFIDENCE_OK) + return; + + delta = powerclamp_data.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(); + tsc_now = rdtsc(); + + /* 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); + + /* if we are above target+guard, skip */ + return powerclamp_data.target_ratio + guard <= current_ratio; +} + +/* + * This function calculates runtime from the current target ratio. + * This function gets called under powerclamp_lock. + */ +static unsigned int get_run_time(void) +{ + unsigned int compensated_ratio; + unsigned int runtime; + + /* + * 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. + */ + powerclamp_data.guard = 1 + powerclamp_data.target_ratio / 20; + powerclamp_data.window_size_now = window_size; + + /* + * 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. + */ + compensated_ratio = powerclamp_data.target_ratio + + get_compensation(powerclamp_data.target_ratio); + if (compensated_ratio <= 0) + compensated_ratio = 1; + + runtime = duration * 100 / compensated_ratio - duration; + + return runtime; +} + +/* + * 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; + + u64 msr_now; + u64 tsc_now; + u64 val64; + + msr_now = pkg_state_counter(); + tsc_now = rdtsc(); + + /* 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; + tsc_last = tsc_now; + + mutex_lock(&powerclamp_lock); + if (powerclamp_data.clamping) + schedule_delayed_work(&poll_pkg_cstate_work, HZ); + mutex_unlock(&powerclamp_lock); +} + +static struct idle_inject_device *ii_dev; + +/* + * This function is called from idle injection core on timer expiry + * for the run duration. This allows powerclamp to readjust or skip + * injecting idle for this cycle. + */ +static bool idle_inject_update(void) +{ + bool update = false; + + /* We can't sleep in this callback */ + if (!mutex_trylock(&powerclamp_lock)) + return true; + + if (!(powerclamp_data.count % powerclamp_data.window_size_now)) { + + should_skip = powerclamp_adjust_controls(powerclamp_data.target_ratio, + powerclamp_data.guard, + powerclamp_data.window_size_now); + update = true; + } + + if (update) { + unsigned int runtime = get_run_time(); + + idle_inject_set_duration(ii_dev, runtime, duration); + } + + powerclamp_data.count++; + + mutex_unlock(&powerclamp_lock); + + if (should_skip) + return false; + + return true; +} + +/* This function starts idle injection by calling idle_inject_start() */ +static void trigger_idle_injection(void) +{ + unsigned int runtime = get_run_time(); + + idle_inject_set_duration(ii_dev, runtime, duration); + idle_inject_start(ii_dev); + powerclamp_data.clamping = true; +} + +/* + * This function is called from start_power_clamp() to register + * CPUS with powercap idle injection register and set default + * idle duration and latency. + */ +static int powerclamp_idle_injection_register(void) +{ + poll_pkg_cstate_enable = false; + if (cpumask_equal(cpu_present_mask, idle_injection_cpu_mask)) { + ii_dev = idle_inject_register_full(idle_injection_cpu_mask, idle_inject_update); + if (topology_max_packages() == 1 && topology_max_die_per_package() == 1) + poll_pkg_cstate_enable = true; + } else { + ii_dev = idle_inject_register(idle_injection_cpu_mask); + } + + if (!ii_dev) { + pr_err("powerclamp: idle_inject_register failed\n"); + return -EAGAIN; + } + + idle_inject_set_duration(ii_dev, TICK_USEC, duration); + idle_inject_set_latency(ii_dev, UINT_MAX); + + return 0; +} + +/* + * This function is called from end_power_clamp() to stop idle injection + * and unregister CPUS from powercap idle injection core. + */ +static void remove_idle_injection(void) +{ + if (!powerclamp_data.clamping) + return; + + powerclamp_data.clamping = false; + idle_inject_stop(ii_dev); +} + +/* + * This function is called when user change the cooling device + * state from zero to some other value. + */ +static int start_power_clamp(void) +{ + int ret; + + ret = powerclamp_idle_injection_register(); + if (!ret) { + trigger_idle_injection(); + if (poll_pkg_cstate_enable) + schedule_delayed_work(&poll_pkg_cstate_work, 0); + } + + return ret; +} + +/* + * This function is called when user change the cooling device + * state from non zero value zero. + */ +static void end_power_clamp(void) +{ + if (powerclamp_data.clamping) { + remove_idle_injection(); + idle_inject_unregister(ii_dev); + } +} + +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) +{ + mutex_lock(&powerclamp_lock); + *state = powerclamp_data.target_ratio; + mutex_unlock(&powerclamp_lock); + + return 0; +} + +static int powerclamp_set_cur_state(struct thermal_cooling_device *cdev, + unsigned long new_target_ratio) +{ + int ret = 0; + + mutex_lock(&powerclamp_lock); + + new_target_ratio = clamp(new_target_ratio, 0UL, + (unsigned long) (max_idle - 1)); + + if (powerclamp_data.target_ratio == new_target_ratio) + goto exit_set; + + if (!powerclamp_data.target_ratio && new_target_ratio > 0) { + pr_info("Start idle injection to reduce power\n"); + powerclamp_data.target_ratio = new_target_ratio; + ret = start_power_clamp(); + if (ret) + powerclamp_data.target_ratio = 0; + goto exit_set; + } else if (powerclamp_data.target_ratio > 0 && new_target_ratio == 0) { + pr_info("Stop forced idle injection\n"); + end_power_clamp(); + powerclamp_data.target_ratio = 0; + } else /* adjust currently running */ { + unsigned int runtime; + + powerclamp_data.target_ratio = new_target_ratio; + runtime = get_run_time(); + idle_inject_set_duration(ii_dev, runtime, duration); + } + +exit_set: + mutex_unlock(&powerclamp_lock); + + return ret; +} + +/* bind to generic thermal layer as cooling device*/ +static const 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, +}; + +static const struct x86_cpu_id __initconst intel_powerclamp_ids[] = { + X86_MATCH_VENDOR_FEATURE(INTEL, X86_FEATURE_MWAIT, NULL), + {} +}; +MODULE_DEVICE_TABLE(x86cpu, intel_powerclamp_ids); + +static int __init powerclamp_probe(void) +{ + + if (!x86_match_cpu(intel_powerclamp_ids)) { + pr_err("CPU does not support MWAIT\n"); + return -ENODEV; + } + + /* The goal for idle time alignment is to achieve package cstate. */ + if (!has_pkg_state_counter()) { + pr_info("No package C-state available\n"); + 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, "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; +} + +DEFINE_SHOW_ATTRIBUTE(powerclamp_debug); + +static inline void powerclamp_create_debug_files(void) +{ + debug_dir = debugfs_create_dir("intel_powerclamp", NULL); + + debugfs_create_file("powerclamp_calib", S_IRUGO, debug_dir, cal_data, + &powerclamp_debug_fops); +} + +static int __init powerclamp_init(void) +{ + int retval; + + /* probe cpu features and ids here */ + retval = powerclamp_probe(); + if (retval) + return retval; + + mutex_lock(&powerclamp_lock); + if (!cpumask_available(idle_injection_cpu_mask)) + retval = allocate_copy_idle_injection_mask(cpu_present_mask); + mutex_unlock(&powerclamp_lock); + + if (retval) + return retval; + + /* set default limit, maybe adjusted during runtime based on feedback */ + window_size = 2; + + cooling_dev = thermal_cooling_device_register("intel_powerclamp", NULL, + &powerclamp_cooling_ops); + if (IS_ERR(cooling_dev)) + return -ENODEV; + + if (!duration) + duration = jiffies_to_usecs(DEFAULT_DURATION_JIFFIES); + + powerclamp_create_debug_files(); + + return 0; +} +module_init(powerclamp_init); + +static void __exit powerclamp_exit(void) +{ + mutex_lock(&powerclamp_lock); + end_power_clamp(); + mutex_unlock(&powerclamp_lock); + + thermal_cooling_device_unregister(cooling_dev); + + cancel_delayed_work_sync(&poll_pkg_cstate_work); + debugfs_remove_recursive(debug_dir); + + if (cpumask_available(idle_injection_cpu_mask)) + free_cpumask_var(idle_injection_cpu_mask); +} +module_exit(powerclamp_exit); + +MODULE_IMPORT_NS(IDLE_INJECT); + +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"); |