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| author | nicolargo <nicolas@nicolargo.com> | 2016-10-23 10:54:03 +0200 |
|---|---|---|
| committer | nicolargo <nicolas@nicolargo.com> | 2016-10-23 10:54:03 +0200 |
| commit | 80cc297a35e5744b88cf1372e6f85332a6353cd5 (patch) | |
| tree | 28c1d5ac7f48bc631364c88298b0e4594c6f79ae /docs | |
| parent | 86fb5efdbf15bfdb98b0bd7c74c458dfe67ec47a (diff) | |
Update CPU docs
Diffstat (limited to 'docs')
| -rw-r--r-- | docs/aoa/cpu.rst | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/docs/aoa/cpu.rst b/docs/aoa/cpu.rst index 9af80ff8..c8acde26 100644 --- a/docs/aoa/cpu.rst +++ b/docs/aoa/cpu.rst @@ -16,13 +16,21 @@ displayed. CPU stats description: * user: percent time spent in user space +> User CPU time is time spent on the processor running your program's code (or code in libraries) * system: percent time spent in kernel space +> System CPU time is the time spent running code in the operating system kernel * idle: percent of CPU used by any program +> Every program or task that runs on a computer system occupies a certain amount of processing time on the CPU. If the CPU has completed all tasks it is idle. * nice: percent time occupied by user level processes with a positive nice value +> The time the CPU has spent running users' processes that have been "niced" * irq: percent time spent servicing/handling hardware/software interrupts +> Time servicing interrupts (hardware + software) * iowait: percent time spent in wait (on disk) -* steal: percent time in involuntary wait by virtual cpu while hypervisor is servicing another processor/virtual machine +> Time spent by the CPU waiting for a IO operations to complete +* steal: percent time in involuntary wait by virtual CPU +> Steal time is the percentage of time a virtual CPU waits for a real CPU while the hypervisor is servicing another virtual processor * ctx_sw: number of context switches (voluntary + involuntary) per second +> A context switch is a procedure that a computer's CPU (central processing unit) follows to change from one task (or process) to another while ensuring that the tasks do not conflict * inter: number of interrupts per second * sw_inter: number of software interrupts per second. Always set to 0 on Windows and SunOS. * syscal: number of system calls per second. Do not displayed on Linux (always 0). |