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178 lines
4.0 KiB
178 lines
4.0 KiB
/* Copyright (c) 2013-2014, 2017 The Linux Foundation. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 and
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* only version 2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include <linux/uaccess.h>
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#include <linux/debugfs.h>
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#include <linux/cpu.h>
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#include <linux/tracepoint.h>
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#include <trace/events/sched.h>
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#define CREATE_TRACE_POINTS
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#include "perf_trace_counters.h"
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static unsigned int tp_pid_state;
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DEFINE_PER_CPU(u32, cntenset_val);
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DEFINE_PER_CPU(u32, previous_ccnt);
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DEFINE_PER_CPU(u32[NUM_L1_CTRS], previous_l1_cnts);
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DEFINE_PER_CPU(u32, old_pid);
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DEFINE_PER_CPU(u32, hotplug_flag);
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#define USE_CPUHP_STATE CPUHP_AP_ONLINE
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static int tracectr_cpu_hotplug_coming_up(unsigned int cpu)
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{
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per_cpu(hotplug_flag, cpu) = 1;
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return 0;
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}
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static void setup_prev_cnts(u32 cpu, u32 cnten_val)
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{
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int i;
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if (cnten_val & CC)
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per_cpu(previous_ccnt, cpu) =
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read_sysreg(pmccntr_el0);
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for (i = 0; i < NUM_L1_CTRS; i++) {
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if (cnten_val & (1 << i)) {
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/* Select */
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write_sysreg(i, pmselr_el0);
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isb();
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/* Read value */
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per_cpu(previous_l1_cnts[i], cpu) =
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read_sysreg(pmxevcntr_el0);
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}
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}
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}
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void tracectr_notifier(void *ignore, bool preempt,
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struct task_struct *prev, struct task_struct *next)
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{
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u32 cnten_val;
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int current_pid;
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u32 cpu = task_cpu(next);
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if (tp_pid_state != 1)
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return;
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current_pid = next->pid;
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if (per_cpu(old_pid, cpu) != -1) {
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cnten_val = read_sysreg(pmcntenset_el0);
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per_cpu(cntenset_val, cpu) = cnten_val;
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/* Disable all the counters that were enabled */
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write_sysreg(cnten_val, pmcntenclr_el0);
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if (per_cpu(hotplug_flag, cpu) == 1) {
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per_cpu(hotplug_flag, cpu) = 0;
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setup_prev_cnts(cpu, cnten_val);
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} else {
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trace_sched_switch_with_ctrs(per_cpu(old_pid, cpu),
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current_pid);
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}
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/* Enable all the counters that were disabled */
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write_sysreg(cnten_val, pmcntenset_el0);
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}
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per_cpu(old_pid, cpu) = current_pid;
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}
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static void enable_tp_pid(void)
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{
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if (tp_pid_state == 0) {
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tp_pid_state = 1;
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register_trace_sched_switch(tracectr_notifier, NULL);
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}
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}
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static void disable_tp_pid(void)
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{
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if (tp_pid_state == 1) {
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tp_pid_state = 0;
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unregister_trace_sched_switch(tracectr_notifier, NULL);
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}
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}
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static ssize_t read_enabled_perftp_file_bool(struct file *file,
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char __user *user_buf, size_t count, loff_t *ppos)
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{
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char buf[2];
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buf[1] = '\n';
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if (tp_pid_state == 0)
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buf[0] = '0';
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else
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buf[0] = '1';
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return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
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}
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static ssize_t write_enabled_perftp_file_bool(struct file *file,
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const char __user *user_buf, size_t count, loff_t *ppos)
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{
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char buf[32];
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size_t buf_size;
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buf[0] = 0;
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buf_size = min(count, (sizeof(buf)-1));
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if (copy_from_user(buf, user_buf, buf_size))
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return -EFAULT;
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switch (buf[0]) {
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case 'y':
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case 'Y':
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case '1':
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enable_tp_pid();
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break;
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case 'n':
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case 'N':
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case '0':
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disable_tp_pid();
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break;
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}
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return count;
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}
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static const struct file_operations fops_perftp = {
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.read = read_enabled_perftp_file_bool,
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.write = write_enabled_perftp_file_bool,
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.llseek = default_llseek,
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};
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int __init init_tracecounters(void)
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{
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struct dentry *dir;
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struct dentry *file;
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unsigned int value = 1;
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int cpu, rc;
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dir = debugfs_create_dir("perf_debug_tp", NULL);
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if (!dir)
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return -ENOMEM;
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file = debugfs_create_file("enabled", 0660, dir,
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&value, &fops_perftp);
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if (!file) {
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debugfs_remove(dir);
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return -ENOMEM;
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}
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for_each_possible_cpu(cpu)
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per_cpu(old_pid, cpu) = -1;
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rc = cpuhp_setup_state_nocalls(USE_CPUHP_STATE,
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"tracectr_cpu_hotplug",
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tracectr_cpu_hotplug_coming_up,
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NULL);
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return 0;
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}
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int __exit exit_tracecounters(void)
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{
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cpuhp_remove_state_nocalls(USE_CPUHP_STATE);
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return 0;
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}
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late_initcall(init_tracecounters);
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