====== proc_stat plugin ======

This plugin provides an interface to the /proc/stat file.

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===== Functions =====

|proc_stat(key)|parse absolute values from /proc/stat|
|proc_stat(key, delay)|parse delta values from /proc/stat|
|proc_stat::cpu(key, delay)|parse cpu info from /proc/stat|
|proc_stat::disk(device, key, delay)|parse disk info from /proc/stat|

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==== proc_stat(key) ====

Valid keys are:

|page.in|number of page-in events|
|page.out|number of page-out events|
|swap.in|number of swap-in events|
|swap.out|number of swap-out events|
|intr.<n>|number of interrupts #n|
|intr.sum|total number of interrupts|

all other entries from /proc/stat are provided verbatim, with the first column as a key. Do a 'cat /proc/stat' to see which values are supported on your system.

The 'delay' value specifies a period of time (in milliseconds) for a delta computation. If you use a delta of 0 (zero) or omit the delta parameter, you get the absolute values (same as in /proc/stat). For delay values > 0 you get the delta value in 1/sec unit. Using a delta value of 500 msec seems to be a good choice.

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==== proc_stat::cpu(key, delay) ====

Valid keys are:

|user|percentage spent in user mode (0..100)|
|nice|percentage spent in niced tasks (0..100)|
|system|percentage spent in kernel mode (0..100)|
|iowait|percentage spent in kernel mode (0..100)|
|irq|percentage spent in kernel mode (0..100)|
|softirq|percentage spent in kernel mode (0..100)|
|idle|percentage idle (0..100)|
|busy|percentage busy (100-idle)|

The 'delay' value specifies a period of time (in milliseconds) for a delta computation. If you use a delta of 0 (zero), you get the absolute values (same as in /proc/stat). For delay values > 0 you get the delta value in 1/sec unit. Using a delta value of 500 msec seems to be a good choice.

Keys iowait,irq and softirq can be used only with **Kernel 2.6**
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==== proc_stat::disk(device, key, delay) ====

The 'device' parameter specifies the device in the form 'major:minor'. Do a 'cat /proc/stat' to see which devices are available on your system. Note that the 'device' field is interpreted as a 'regular expression' (regex), if you use a regex you get the sum of all matching devices (e.g. 'proc_stat::disk ('3:.*', 'rblk', 500)' will return the sum of read blocks for 3:0, 3:1, 3:2, ...)

Valid keys are:

|io|total number of disk I/O events|
|rio|number of disk read events|
|rblk|number of blocks read from disk|
|wio|number of disk write events|
|wblk|number of blocks written to disk|

The 'delay' value specifies a period of time (in milliseconds) for a delta computation. If you use a delta of 0 (zero), you get the absolute values (same as in /proc/diskstats). For delay values > 0 you get the delta value in 1/sec unit. Using a delta value of 500 msec seems to be a good choice.

**Kernel 2.6**: With Kernel 2.6, the 'disk_io' lines disappeared from /proc/stat, and therefore you'll get no results with this plugin. Use the [[:plugin_diskstats|diskstats-plugin]] instead!

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===== Example =====

<code>
Widget BusyBar {
    class 'Bar'
    expression  proc_stat::cpu('busy',   500)
    expression2 proc_stat::cpu('system', 500)
    length 10	
    direction 'E'
    update 100
}

Widget Disk {
    class 'Text'
    expression (proc_stat::disk('.*', 'rblk', 500) + proc_stat::disk('.*', 'wblk', 500))/2
    prefix 'I/O'
    width 10	
    precision 0
    align 'R'	
    update 100
}	

</code>


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