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
(size_t *entries);

sg_cpu_percents *sg_get_cpu_percents_of
(sg_cpu_percent_source cps, size_t *entries);

sg_cpu_percents *sg_get_cpu_percents_r
(const sg_cpu_stats *whereof, size_t *entries);

void sg_free_cpu_percents
(sg_cpu_percents *data);

sg_cpu_stats *sg_get_cpu_stats
(size_t *entries);

sg_cpu_stats *sg_get_cpu_stats_diff
(size_t *entries);

sg_cpu_stats *sg_get_cpu_stats_r
(size_t *entries);

sg_cpu_stats *sg_get_cpu_stats_diff_between
(const sg_cpu_stats *cpu_now, const sg_cpu_stats *cpu_last, size_t *entries);

sg_error sg_free_cpu_stats
(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%).

API Shortcut

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.

SEE ALSO¶

statgrab(3)

WEBSITE¶

⟨https://libstatgrab.org/⟩