#!/usr/bin/env bpftrace
/*
* loads Prints load averages.
* For Linux, uses bpftrace and eBPF.
*
* These are the same load averages printed by "uptime", but to three decimal
* places instead of two (not that it really matters). This is really a
* demonstration of fetching and processing a kernel structure from bpftrace.
*
* USAGE: loads.bt
*
* This is a bpftrace version of a DTraceToolkit tool.
*
* Copyright 2018 Netflix, Inc.
* Licensed under the Apache License, Version 2.0 (the "License")
*
* 10-Sep-2018 Brendan Gregg Created this.
*/
BEGIN
{
printf("Reading load averages... Hit Ctrl-C to end.\n");
}
interval:s:1
{
/*
* See fs/proc/loadavg.c and include/linux/sched/loadavg.h for the
* following calculations.
*/
$avenrun = kaddr("avenrun");
$load1 = *$avenrun;
$load5 = *($avenrun + 8);
$load15 = *($avenrun + 16);
time("%H:%M:%S ");
printf("load averages: %d.%03d %d.%03d %d.%03d\n",
($load1 >> 11), (($load1 & ((1 << 11) - 1)) * 1000) >> 11,
($load5 >> 11), (($load5 & ((1 << 11) - 1)) * 1000) >> 11,
($load15 >> 11), (($load15 & ((1 << 11) - 1)) * 1000) >> 11
);
}
Mini Shell