sg_get_cpu

Name

sg_get_cpu_stats, sg_get_cpu_stats_r, sg_get_cpu_stats_diff, sg_get_cpu_stats_diff_between, sg_get_cpu_percents, sg_get_cpu_percents_of, sg_get_cpu_percents_r, sg_free_cpu_stats — get cpu usage

Synopsis

#include <statgrab.h>

sg_cpu_percents *sg_get_cpu_percents( entries);

size_t *entries;

`sg_cpu_percents *sg_get_cpu_percents_of(`	`cps`,
	`entries)`;

sg_cpu_percent_source cps;
size_t *entries;

`sg_cpu_percents *sg_get_cpu_percents_r(`	`whereof`,
	`entries)`;

const sg_cpu_stats *whereof;
size_t *entries;

void sg_free_cpu_percents( data);

sg_cpu_percents *data;

sg_cpu_stats *sg_get_cpu_stats( entries);

size_t *entries;

sg_cpu_stats *sg_get_cpu_stats_diff( entries);

size_t *entries;

sg_cpu_stats *sg_get_cpu_stats_r( entries);

size_t *entries;

`sg_cpu_stats *sg_get_cpu_stats_diff_between(`	`cpu_nowcpu_last`,
	`entries)`;

const sg_cpu_stats *cpu_now, const sg_cpu_stats *cpu_last;
size_t *entries;

sg_error sg_free_cpu_stats( data);

sg_cpu_stats *data;

Description

These are the categories of data delivered by the cpu stats module: sg_get_cpu_stats() and sg_get_cpu_stats_r() deliver native cpu counters since the machine has been started, sg_get_cpu_stats_diff() and sg_get_cpu_stats_diff_between() deliver native cpu counters between two sg_get_cpu_stats() calls and sg_get_cpu_percents_of() and sg_get_cpu_percents_r() deliver correlated relative cpu counters (where total is 100%).

Table 1. API Shortcut

function	returns	data owner
sg_get_cpu_stats	sg_cpu_stats *	libstatgrab (thread local)
sg_get_cpu_stats_r	sg_cpu_stats *	caller
sg_get_cpu_stats_diff	sg_cpu_stats *	libstatgrab (thread local)
sg_get_cpu_stats_diff_between	sg_cpu_stats *	caller
sg_get_cpu_percents_of	sg_cpu_percents *	libstatgrab (thread local)
sg_get_cpu_percents_r	sg_cpu_percents *	caller

The sg_cpu_stats buffer received from sg_get_cpu_stats_r() and the sg_get_cpu_stats_diff_between() as well as the sg_cpu_percents buffer received from sg_get_cpu_percents_r() must be freed using sg_free_cpu_stats() or the sg_free_cpu_percents(), respectively, when not needed any more. The caller is responsible for doing it.

The value stored (the "ticks") will vary between operating systems. For example Solaris has a total of 100 per second, while Linux has substantially more. Also, different operating systems store different information - you won't find nice cpu on Solaris for example.

Modern systems shall provide information about the clock tick resolution by invoking sysconf(_SC_CLK_TCK).

Return Values

There are two structures returned by the CPU statistics functions.

typedef struct {
        unsigned long long user;
        unsigned long long kernel;
        unsigned long long idle;
        unsigned long long iowait;
        unsigned long long swap;
        unsigned long long nice;
        unsigned long long total;

        unsigned long long context_switches;
        unsigned long long voluntary_context_switches;
        unsigned long long involuntary_context_switches;
        unsigned long long syscalls;
        unsigned long long interrupts;
        unsigned long long soft_interrupts;

        time_t systime;
} sg_cpu_stats;

typedef struct {
        double user;
        double kernel;
        double idle;
        double iowait;
        double swap;
        double nice;
        time_t time_taken;
} sg_cpu_percents;

user kernel idle iowait swap nice total: The different CPU states.
context_switches voluntary_context_switches involuntary_context_switches syscalls interrupts soft_interrupts: The different program actions on CPU.
systime time_taken: The time taken in seconds since the last call of the function, or the system time.

Website

https://libstatgrab.org/

Name

Synopsis

Description

Return Values

See Also

Website