#!/usr/bin/env bpftrace
/*
* runqlen.bt CPU scheduler run queue length as a histogram.
* For Linux, uses bpftrace, eBPF.
*
* This is a bpftrace version of the bcc tool of the same name.
*
* Copyright 2018 Netflix, Inc.
* Licensed under the Apache License, Version 2.0 (the "License")
*
* 07-Oct-2018 Brendan Gregg Created this.
*/
#ifndef BPFTRACE_HAVE_BTF
#include <linux/sched.h>
// Until BTF is available, we'll need to declare some of this struct manually,
// since it isn't available to be #included. This will need maintenance to match
// your kernel version. It is from kernel/sched/sched.h:
struct cfs_rq {
struct load_weight load;
unsigned int nr_running;
unsigned int h_nr_running;
};
#endif
BEGIN
{
printf("Sampling run queue length at 99 Hertz... Hit Ctrl-C to end.\n");
}
profile:hz:99
{
$task = (struct task_struct *)curtask;
$my_q = (struct cfs_rq *)$task->se.cfs_rq;
$len = $my_q->nr_running;
$len = $len > 0 ? $len - 1 : 0; // subtract currently running task
@runqlen = lhist($len, 0, 100, 1);
}
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