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![Ken Chen](/assets/img/avatar_default.png)
schedstat is useful in investigating CPU scheduler behavior. Ideally, I think it is beneficial to have it on all the time. However, the cost of turning it on in production system is quite high, largely due to number of events it collects and also due to its large memory footprint. Most of the fields probably don't need to be full 64-bit on 64-bit arch. Rolling over 4 billion events will most like take a long time and user space tool can be made to accommodate that. I'm proposing kernel to cut back most of variable width on 64-bit system. (note, the following patch doesn't affect 32-bit system). Signed-off-by: Ken Chen <kenchen@google.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
393 lines
9.1 KiB
C
393 lines
9.1 KiB
C
/*
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* kernel/time/sched_debug.c
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*
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* Print the CFS rbtree
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*
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* Copyright(C) 2007, Red Hat, Inc., Ingo Molnar
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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 as
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* published by the Free Software Foundation.
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*/
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#include <linux/proc_fs.h>
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#include <linux/sched.h>
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#include <linux/seq_file.h>
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#include <linux/kallsyms.h>
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#include <linux/utsname.h>
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/*
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* This allows printing both to /proc/sched_debug and
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* to the console
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*/
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#define SEQ_printf(m, x...) \
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do { \
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if (m) \
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seq_printf(m, x); \
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else \
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printk(x); \
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} while (0)
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/*
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* Ease the printing of nsec fields:
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*/
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static long long nsec_high(long long nsec)
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{
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if (nsec < 0) {
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nsec = -nsec;
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do_div(nsec, 1000000);
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return -nsec;
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}
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do_div(nsec, 1000000);
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return nsec;
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}
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static unsigned long nsec_low(long long nsec)
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{
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if (nsec < 0)
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nsec = -nsec;
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return do_div(nsec, 1000000);
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}
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#define SPLIT_NS(x) nsec_high(x), nsec_low(x)
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static void
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print_task(struct seq_file *m, struct rq *rq, struct task_struct *p)
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{
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if (rq->curr == p)
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SEQ_printf(m, "R");
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else
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SEQ_printf(m, " ");
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SEQ_printf(m, "%15s %5d %9Ld.%06ld %9Ld %5d ",
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p->comm, p->pid,
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SPLIT_NS(p->se.vruntime),
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(long long)(p->nvcsw + p->nivcsw),
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p->prio);
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#ifdef CONFIG_SCHEDSTATS
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SEQ_printf(m, "%9Ld.%06ld %9Ld.%06ld %9Ld.%06ld\n",
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SPLIT_NS(p->se.vruntime),
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SPLIT_NS(p->se.sum_exec_runtime),
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SPLIT_NS(p->se.sum_sleep_runtime));
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#else
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SEQ_printf(m, "%15Ld %15Ld %15Ld.%06ld %15Ld.%06ld %15Ld.%06ld\n",
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0LL, 0LL, 0LL, 0L, 0LL, 0L, 0LL, 0L);
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#endif
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}
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static void print_rq(struct seq_file *m, struct rq *rq, int rq_cpu)
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{
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struct task_struct *g, *p;
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SEQ_printf(m,
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"\nrunnable tasks:\n"
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" task PID tree-key switches prio"
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" exec-runtime sum-exec sum-sleep\n"
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"------------------------------------------------------"
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"----------------------------------------------------\n");
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read_lock_irq(&tasklist_lock);
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do_each_thread(g, p) {
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if (!p->se.on_rq || task_cpu(p) != rq_cpu)
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continue;
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print_task(m, rq, p);
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} while_each_thread(g, p);
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read_unlock_irq(&tasklist_lock);
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}
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void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq)
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{
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s64 MIN_vruntime = -1, min_vruntime, max_vruntime = -1,
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spread, rq0_min_vruntime, spread0;
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struct rq *rq = &per_cpu(runqueues, cpu);
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struct sched_entity *last;
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unsigned long flags;
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SEQ_printf(m, "\ncfs_rq\n");
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SEQ_printf(m, " .%-30s: %Ld.%06ld\n", "exec_clock",
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SPLIT_NS(cfs_rq->exec_clock));
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spin_lock_irqsave(&rq->lock, flags);
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if (cfs_rq->rb_leftmost)
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MIN_vruntime = (__pick_next_entity(cfs_rq))->vruntime;
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last = __pick_last_entity(cfs_rq);
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if (last)
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max_vruntime = last->vruntime;
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min_vruntime = rq->cfs.min_vruntime;
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rq0_min_vruntime = per_cpu(runqueues, 0).cfs.min_vruntime;
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spin_unlock_irqrestore(&rq->lock, flags);
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SEQ_printf(m, " .%-30s: %Ld.%06ld\n", "MIN_vruntime",
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SPLIT_NS(MIN_vruntime));
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SEQ_printf(m, " .%-30s: %Ld.%06ld\n", "min_vruntime",
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SPLIT_NS(min_vruntime));
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SEQ_printf(m, " .%-30s: %Ld.%06ld\n", "max_vruntime",
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SPLIT_NS(max_vruntime));
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spread = max_vruntime - MIN_vruntime;
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SEQ_printf(m, " .%-30s: %Ld.%06ld\n", "spread",
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SPLIT_NS(spread));
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spread0 = min_vruntime - rq0_min_vruntime;
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SEQ_printf(m, " .%-30s: %Ld.%06ld\n", "spread0",
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SPLIT_NS(spread0));
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SEQ_printf(m, " .%-30s: %ld\n", "nr_running", cfs_rq->nr_running);
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SEQ_printf(m, " .%-30s: %ld\n", "load", cfs_rq->load.weight);
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#ifdef CONFIG_SCHEDSTATS
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SEQ_printf(m, " .%-30s: %d\n", "bkl_count",
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rq->bkl_count);
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#endif
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SEQ_printf(m, " .%-30s: %ld\n", "nr_spread_over",
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cfs_rq->nr_spread_over);
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}
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static void print_cpu(struct seq_file *m, int cpu)
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{
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struct rq *rq = &per_cpu(runqueues, cpu);
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#ifdef CONFIG_X86
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{
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unsigned int freq = cpu_khz ? : 1;
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SEQ_printf(m, "\ncpu#%d, %u.%03u MHz\n",
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cpu, freq / 1000, (freq % 1000));
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}
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#else
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SEQ_printf(m, "\ncpu#%d\n", cpu);
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#endif
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#define P(x) \
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SEQ_printf(m, " .%-30s: %Ld\n", #x, (long long)(rq->x))
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#define PN(x) \
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SEQ_printf(m, " .%-30s: %Ld.%06ld\n", #x, SPLIT_NS(rq->x))
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P(nr_running);
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SEQ_printf(m, " .%-30s: %lu\n", "load",
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rq->load.weight);
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P(nr_switches);
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P(nr_load_updates);
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P(nr_uninterruptible);
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SEQ_printf(m, " .%-30s: %lu\n", "jiffies", jiffies);
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PN(next_balance);
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P(curr->pid);
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PN(clock);
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PN(idle_clock);
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PN(prev_clock_raw);
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P(clock_warps);
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P(clock_overflows);
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P(clock_deep_idle_events);
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PN(clock_max_delta);
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P(cpu_load[0]);
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P(cpu_load[1]);
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P(cpu_load[2]);
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P(cpu_load[3]);
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P(cpu_load[4]);
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#undef P
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#undef PN
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print_cfs_stats(m, cpu);
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print_rq(m, rq, cpu);
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}
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static int sched_debug_show(struct seq_file *m, void *v)
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{
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u64 now = ktime_to_ns(ktime_get());
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int cpu;
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SEQ_printf(m, "Sched Debug Version: v0.06-v22, %s %.*s\n",
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init_utsname()->release,
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(int)strcspn(init_utsname()->version, " "),
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init_utsname()->version);
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SEQ_printf(m, "now at %Lu.%06ld msecs\n", SPLIT_NS(now));
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#define P(x) \
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SEQ_printf(m, " .%-40s: %Ld\n", #x, (long long)(x))
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#define PN(x) \
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SEQ_printf(m, " .%-40s: %Ld.%06ld\n", #x, SPLIT_NS(x))
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PN(sysctl_sched_latency);
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PN(sysctl_sched_nr_latency);
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PN(sysctl_sched_wakeup_granularity);
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PN(sysctl_sched_batch_wakeup_granularity);
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PN(sysctl_sched_child_runs_first);
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P(sysctl_sched_features);
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#undef PN
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#undef P
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for_each_online_cpu(cpu)
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print_cpu(m, cpu);
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SEQ_printf(m, "\n");
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return 0;
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}
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static void sysrq_sched_debug_show(void)
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{
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sched_debug_show(NULL, NULL);
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}
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static int sched_debug_open(struct inode *inode, struct file *filp)
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{
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return single_open(filp, sched_debug_show, NULL);
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}
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static const struct file_operations sched_debug_fops = {
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.open = sched_debug_open,
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.read = seq_read,
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.llseek = seq_lseek,
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.release = single_release,
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};
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static int __init init_sched_debug_procfs(void)
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{
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struct proc_dir_entry *pe;
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pe = create_proc_entry("sched_debug", 0644, NULL);
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if (!pe)
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return -ENOMEM;
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pe->proc_fops = &sched_debug_fops;
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return 0;
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}
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__initcall(init_sched_debug_procfs);
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void proc_sched_show_task(struct task_struct *p, struct seq_file *m)
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{
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unsigned long nr_switches;
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unsigned long flags;
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int num_threads = 1;
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rcu_read_lock();
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if (lock_task_sighand(p, &flags)) {
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num_threads = atomic_read(&p->signal->count);
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unlock_task_sighand(p, &flags);
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}
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rcu_read_unlock();
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SEQ_printf(m, "%s (%d, #threads: %d)\n", p->comm, p->pid, num_threads);
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SEQ_printf(m,
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"---------------------------------------------------------\n");
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#define __P(F) \
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SEQ_printf(m, "%-35s:%21Ld\n", #F, (long long)F)
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#define P(F) \
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SEQ_printf(m, "%-35s:%21Ld\n", #F, (long long)p->F)
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#define __PN(F) \
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SEQ_printf(m, "%-35s:%14Ld.%06ld\n", #F, SPLIT_NS((long long)F))
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#define PN(F) \
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SEQ_printf(m, "%-35s:%14Ld.%06ld\n", #F, SPLIT_NS((long long)p->F))
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PN(se.exec_start);
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PN(se.vruntime);
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PN(se.sum_exec_runtime);
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nr_switches = p->nvcsw + p->nivcsw;
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#ifdef CONFIG_SCHEDSTATS
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PN(se.wait_start);
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PN(se.sleep_start);
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PN(se.block_start);
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PN(se.sleep_max);
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PN(se.block_max);
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PN(se.exec_max);
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PN(se.slice_max);
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PN(se.wait_max);
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P(sched_info.bkl_count);
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P(se.nr_migrations);
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P(se.nr_migrations_cold);
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P(se.nr_failed_migrations_affine);
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P(se.nr_failed_migrations_running);
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P(se.nr_failed_migrations_hot);
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P(se.nr_forced_migrations);
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P(se.nr_forced2_migrations);
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P(se.nr_wakeups);
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P(se.nr_wakeups_sync);
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P(se.nr_wakeups_migrate);
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P(se.nr_wakeups_local);
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P(se.nr_wakeups_remote);
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P(se.nr_wakeups_affine);
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P(se.nr_wakeups_affine_attempts);
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P(se.nr_wakeups_passive);
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P(se.nr_wakeups_idle);
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{
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u64 avg_atom, avg_per_cpu;
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avg_atom = p->se.sum_exec_runtime;
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if (nr_switches)
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do_div(avg_atom, nr_switches);
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else
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avg_atom = -1LL;
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avg_per_cpu = p->se.sum_exec_runtime;
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if (p->se.nr_migrations)
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avg_per_cpu = div64_64(avg_per_cpu, p->se.nr_migrations);
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else
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avg_per_cpu = -1LL;
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__PN(avg_atom);
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__PN(avg_per_cpu);
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}
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#endif
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__P(nr_switches);
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SEQ_printf(m, "%-35s:%21Ld\n",
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"nr_voluntary_switches", (long long)p->nvcsw);
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SEQ_printf(m, "%-35s:%21Ld\n",
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"nr_involuntary_switches", (long long)p->nivcsw);
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P(se.load.weight);
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P(policy);
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P(prio);
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#undef PN
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#undef __PN
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#undef P
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#undef __P
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{
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u64 t0, t1;
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t0 = sched_clock();
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t1 = sched_clock();
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SEQ_printf(m, "%-35s:%21Ld\n",
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"clock-delta", (long long)(t1-t0));
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}
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}
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void proc_sched_set_task(struct task_struct *p)
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{
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#ifdef CONFIG_SCHEDSTATS
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p->se.wait_max = 0;
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p->se.sleep_max = 0;
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p->se.sum_sleep_runtime = 0;
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p->se.block_max = 0;
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p->se.exec_max = 0;
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p->se.slice_max = 0;
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p->se.nr_migrations = 0;
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p->se.nr_migrations_cold = 0;
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p->se.nr_failed_migrations_affine = 0;
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p->se.nr_failed_migrations_running = 0;
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p->se.nr_failed_migrations_hot = 0;
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p->se.nr_forced_migrations = 0;
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p->se.nr_forced2_migrations = 0;
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p->se.nr_wakeups = 0;
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p->se.nr_wakeups_sync = 0;
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p->se.nr_wakeups_migrate = 0;
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p->se.nr_wakeups_local = 0;
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p->se.nr_wakeups_remote = 0;
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p->se.nr_wakeups_affine = 0;
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p->se.nr_wakeups_affine_attempts = 0;
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p->se.nr_wakeups_passive = 0;
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p->se.nr_wakeups_idle = 0;
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p->sched_info.bkl_count = 0;
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#endif
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p->se.sum_exec_runtime = 0;
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p->se.prev_sum_exec_runtime = 0;
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p->nvcsw = 0;
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p->nivcsw = 0;
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}
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