From: Roman Gushchin <[email protected]> This patch introduces debug infrastructure for smart. The infrastructure contains a number of per-cpu counters, smart_event() function to register smart-related events and procfs interface to read and reset these counters.
The following events are counting: pull - smart pull balance_local - local cpu selection balance_remote - remote cpu selection select_core - free local core selected select_rcore - free remote core selected select_thread - free local cpu selected select_rthread - free remote cpu selected select_busy - busy cpu selected select_busy_curr - current busy cpu selected select_fallback - select_fallback_rq() called rt_pull - rt push rt_push - rt pull Signed-off-by: Roman Gushchin <[email protected]> --- init/Kconfig | 8 +++++ kernel/sched/core.c | 3 ++ kernel/sched/rt.c | 85 +++++++++++++++++++++++++++++++++++++++++++++++++++- kernel/sched/sched.h | 38 +++++++++++++++++++++++ 4 files changed, 133 insertions(+), 1 deletion(-) diff --git a/init/Kconfig b/init/Kconfig index 98dd173..d936b49 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -813,6 +813,14 @@ config SMART enabled hyper-threading. Do not use for hard real-time purposes. +config SMART_DEBUG + bool "Enable SMART debug features" + default y + depends on SMART + help + This option adds gathering of SMART statistics. It's + available via /proc/smart_stat interface. + menuconfig CGROUPS boolean "Control Group support" depends on EVENTFD diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 5954f48..c2b988c 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1180,6 +1180,9 @@ static int select_fallback_rq(int cpu, struct task_struct *p) enum { cpuset, possible, fail } state = cpuset; int dest_cpu; + if (smart_enabled() && task_has_rt_policy(p)) + smart_event(select_fallback); + /* * If the node that the cpu is on has been offlined, cpu_to_node() * will return -1. There is no cpu on the node, and we should diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c index 8621443..14acd51 100644 --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -9,8 +9,69 @@ #ifdef CONFIG_SMART #include <linux/workqueue.h> +#include <linux/proc_fs.h> + +#ifdef CONFIG_SMART_DEBUG +#include <linux/seq_file.h> #include <linux/jump_label.h> +DEFINE_PER_CPU(struct smart_stat, smart_stat); + +static struct proc_dir_entry *smart_pde; + +static ssize_t smart_proc_write(struct file *file, const char __user *buffer, + size_t count, loff_t *ppos) +{ + int c; + + for_each_possible_cpu(c) + memset(&per_cpu(smart_stat, c), 0, sizeof(struct smart_stat)); + + return count; +} + +#define smart_stat_print(m, field) \ + ({ \ + u64 res = 0; \ + unsigned int c; \ + for_each_possible_cpu(c) \ + res += per_cpu(smart_stat, c).field; \ + seq_printf(m, "%-16s %llu\n", #field, res); \ + }) + +static int smart_proc_show(struct seq_file *m, void *arg) +{ + smart_stat_print(m, pull); + smart_stat_print(m, balance_local); + smart_stat_print(m, balance_remote); + smart_stat_print(m, select_core); + smart_stat_print(m, select_rcore); + smart_stat_print(m, select_thread); + smart_stat_print(m, select_rthread); + smart_stat_print(m, select_busy); + smart_stat_print(m, select_busy_curr); + smart_stat_print(m, select_fallback); + smart_stat_print(m, rt_pull); + smart_stat_print(m, rt_push); + + return 0; +} + +static int smart_proc_open(struct inode *inode, struct file *file) +{ + return single_open(file, smart_proc_show, NULL); +} + +static const struct file_operations smart_proc_fops = { + .owner = THIS_MODULE, + .open = smart_proc_open, + .read = seq_read, + .write = smart_proc_write, + .llseek = seq_lseek, + .release = single_release, +}; +#endif + struct static_key __smart_initialized = STATIC_KEY_INIT_FALSE; struct static_key __smart_enabled = STATIC_KEY_INIT_TRUE; DEFINE_MUTEX(smart_mutex); @@ -1773,6 +1834,9 @@ retry: out: put_task_struct(next_task); + if (ret) + smart_event(rt_push); + return ret; } @@ -1859,6 +1923,9 @@ skip: double_unlock_balance(this_rq, src_rq); } + if (ret) + smart_event(rt_pull); + return ret; } @@ -2270,6 +2337,13 @@ void build_smart_topology(void) if (was_initialized) printk(KERN_INFO "smart: disabled\n"); +#ifdef CONFIG_SMART_DEBUG + if (!smart_pde) + smart_pde = proc_create("smart_stat", + S_IWUSR | S_IRUSR | S_IRGRP | S_IROTH, + NULL, &smart_proc_fops); +#endif + get_online_cpus(); for_each_online_cpu(cpu) { /* __cpu_core_id */ @@ -2369,6 +2443,9 @@ static int smart_find_lowest_rq(struct task_struct *task, bool wakeup) prev_cpu = core_node_sibling(prev_cpu); } } + + smart_event_node(task_cpu(task), prev_cpu, + balance_local, balance_remote); } for (attempts = 3; attempts; attempts--) { @@ -2376,14 +2453,20 @@ static int smart_find_lowest_rq(struct task_struct *task, bool wakeup) if (best_cpu == -1) { best_cpu = find_rt_best_thread(prev_cpu, task); + smart_event_node(task_cpu(task), best_cpu, + select_thread, select_rthread); + break; } if (!acquire_core(best_cpu)) continue; - if (likely(core_is_rt_free(best_cpu))) + if (likely(core_is_rt_free(best_cpu))) { + smart_event_node(task_cpu(task), best_cpu, + select_core, select_rcore); break; + } release_core(best_cpu); } diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 80d202e..d450b8f 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -1380,6 +1380,38 @@ static inline u64 irq_time_read(int cpu) #endif /* CONFIG_64BIT */ #endif /* CONFIG_IRQ_TIME_ACCOUNTING */ +#ifdef CONFIG_SMART_DEBUG +struct smart_stat { + u64 pull; + u64 balance_local; + u64 balance_remote; + u64 select_core; + u64 select_rcore; + u64 select_thread; + u64 select_rthread; + u64 select_busy; + u64 select_busy_curr; + u64 select_fallback; + u64 rt_pull; + u64 rt_push; +}; + +DECLARE_PER_CPU(struct smart_stat, smart_stat); +#define smart_event(e) do { __get_cpu_var(smart_stat).e++; } while (0) +#define smart_event_node(prev_cpu, next_cpu, local_event, remote_event) \ + do { \ + if (prev_cpu >= 0 && next_cpu >= 0 && \ + cpu_to_node(prev_cpu) == cpu_to_node(next_cpu)) \ + smart_event(local_event); \ + else \ + smart_event(remote_event); \ + } while (0) +#else +#define smart_event(e) do { } while (0) +#define smart_event_node(prev_cpu, next_cpu, local_event, remote_event) \ + do { } while (0) +#endif /* CONFIG_SMART_DEBUG */ + #ifdef CONFIG_SMART struct smart_core_data { int cpu_core_id; @@ -1417,6 +1449,7 @@ static inline int cpu_core_id(int cpu) #define smart_data(cpu) per_cpu(smart_core_data, cpu_core_id(cpu)) #define smart_node_ptr(cpu) smart_node_data[cpu_to_node(cpu)] #define smart_gathering_data(cpu) per_cpu(smart_gathering_data, cpu) +#define smart_stats(cpu) per_cpu(smart_core_data, cpu_core_id(cpu)).stats static inline bool smart_enabled(void) { @@ -1587,6 +1620,11 @@ static inline int find_rt_best_thread(int start_cpu, struct task_struct *task) min_running == cpu_rq(start_cpu)->rt.rt_nr_running) best_cpu = -1; + if (best_cpu == -1 || best_cpu == start_cpu) + smart_event(select_busy_curr); + else + smart_event(select_busy); + return best_cpu; } -- 1.9.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
