// Copyright (C) 2013 Red Hat Inc., Aaron Tomlin <atomlin@redhat.com>
//
// This file is part of systemtap, and is free software.  You can
// redistribute it and/or modify it under the terms of the GNU General
// Public License (GPL); either version 2, or (at your option) any
// later version.

// <tapsetdescription>
// Functions in the loadavg tapset allow a probe handler to capture
// the load average.
// </tapsetdescription>


%{
#include <linux/sched.h>
#if defined(STAPCONF_LINUX_SCHED_HEADERS)
#include <linux/sched/loadavg.h>
#endif

#define LOAD_INT(x) ((x) >> FSHIFT)
#define LOAD_FRAC(x) LOAD_INT(((x) & (FIXED_1-1)) * 100)
%}

/**
 * sfunction get_loadavg_index - Get the load average for a specified interval
 * @indx: The load average interval to capture.
 *
 * Description: This function returns the load average at a specified interval.
 * The three load average values 1, 5 and 15 minute average corresponds to
 * indexes 0, 1 and 2 of the avenrun array - see linux/sched.h.
 * Please note that the truncated-integer portion of the load average is returned.
 * If the specified index is out-of-bounds, then an error message and exception is
 * thrown.
 */
function get_loadavg_index:long (indx:long) %{ /* pure */
	int value;

	if (STAP_ARG_indx < 0 || STAP_ARG_indx > 2)
		STAP_ERROR("Invalid loadavg index %lld specified.",
		STAP_ARG_indx);

	value = avenrun[STAP_ARG_indx] + (FIXED_1/200);

	STAP_RETVALUE = LOAD_INT(value);
%}

/**
 * sfunction sprint_loadavg - Report a pretty-printed load average
 *
 * Description: Returns the a string with three decimal numbers
 * in the usual format for 1-, 5- and 15-minute load averages.
 */
function sprint_loadavg:string () %{ /* pure */ /* stable */
	int a, b, c;

	a = avenrun[0] + (FIXED_1/200);
	b = avenrun[1] + (FIXED_1/200);
	c = avenrun[2] + (FIXED_1/200);

	snprintf(STAP_RETVALUE, MAXSTRINGLEN,
		"%d.%02d %d.%02d %d.%02d\n",
		LOAD_INT(a), LOAD_FRAC(a),
		LOAD_INT(b), LOAD_FRAC(b),
		LOAD_INT(c), LOAD_FRAC(c));
%}