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CPU Statistics |
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cpu_states_t *get_cpu_totals(); |
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cpu_states_t *get_cpu_diff(); |
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cpu_percent_t *cpu_percent_usage(); |
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typedef struct{ |
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long long user; |
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long long kernel; |
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long long idle; |
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long long iowait; |
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long long swap; |
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long long nice; |
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long long total; |
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time_t systime; |
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}cpu_states_t; |
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typedef struct{ |
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float user; |
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float kernel; |
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float idle; |
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float iowait; |
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float swap; |
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float nice; |
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time_t time_taken; |
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}cpu_percent_t; |
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get_cpu_totals() and get_cpu_diff() both return static pointers of |
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type cpu_states_t. get_cpu_totals() returns the total amount of "ticks" |
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the OS has spent in each of the different states. get_cpu_diff() returns |
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the difference in "ticks" for each of the states since last time get_cpu_diff() |
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or get_cpu_totals() was called. If it has never been called, it will return |
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the result of get_cpu_totals() |
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The vaule stored (the "ticks") will vary from OS to OS. E.g. solaris has a |
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total of 100 per second. Linux has substatially more than that. Also, different |
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OS's store different information. E.g. solaris doesn't do nice. |
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Because of this, ideally you will always want to work on a scale against the |
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total, or in percentages. |
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cpu_percent_usage() returns a pointer to a static cpu_percent_t. The function calls |
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get_cpu_diff() and changes the values into percentages. If its never been called |
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before (and nor has get_cpu_totals() and get_cpu_diff() ), the returned percentages |
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will be the systems total ever since its uptime. (Unless the counters of cycled) |
