In Unix/Linux operating systems, processes can be in one of the following states: 1. RUNNING & RUNNABLE 2. INTERRRUPTABLE_SLEEP 3. UNINTERRUPTABLE_SLEEP 4. STOPPED 5. ZOMBIE Let's discuss these states in this article. Fig: Process State transition diagram RUNNING & RUNNABLE When the CPU executes a process, it will be in a RUNNING state. When the... Continue Reading →
What is ‘Load Average’?
Load average is an age-old metric, which is in existence since the 1970s to indicate whether the system is under heavy/average/low load. It is useful to indicate whether the system’s load is on an increasing trend or a decreasing trend. In this article, let’s learn more about ‘Load Average’. How to understand 'Load Average'? In... Continue Reading →
Load Average – indicator for CPU demand only?
'Load Average' is an age-old metric reported in various operating systems. It's often assumed as a metric to indicate the CPU demand only. However, it is not the case. 'Load Average' not only indicates CPU demand, but also the I/O demand (i.e., network read/write, file read/write, disk read/write). To prove this theory, we conducted this... Continue Reading →
Different CPU times – Unix/Linux ‘top’
CPU consumption in Unix/Linux operating systems are studied using 8 different metrics: User CPU time, System CPU time, nice CPU time, Idle CPU time, Waiting CPU time, Hardware Interrupt CPU time, Software Interrupt CPU time, Stolen CPU time. Let’s review each of the CPU time in this article. user CPU time & system CPU time... Continue Reading →
I/O waiting CPU time – ‘wa’ in top
CPU consumption in Unix/Linux operating systems are studied using 8 different metrics: User CPU time, System CPU time, nice CPU time, Idle CPU time, Waiting CPU time, Hardware Interrupt CPU time, Software Interrupt CPU time, Stolen CPU time. In this article let us study about ‘waiting CPU time’. What is ‘waiting’ CPU time? Waiting CPU... Continue Reading →
User CPU time – ‘us’ time in top
CPU consumption in Unix/Linux operating systems are studied using 8 different metrics: User CPU time, System CPU time, nice CPU time, Idle CPU time, Waiting CPU time, Hardware Interrupt CPU time, Software Interrupt CPU time, Stolen CPU time. In this article let us study about ‘User CPU time’. What is ‘user’ CPU time? In order... Continue Reading →
System CPU time – ‘sys’ time in top
CPU consumption in Unix/Linux operating systems are studied using 8 different metrics: User CPU time, System CPU time, nice CPU time, Idle CPU time, Waiting CPU time, Hardware Interrupt CPU time, Software Interrupt CPU time, Stolen CPU time. In this article let us study about ‘System CPU time’. What is ‘system’ CPU time? In order... Continue Reading →
Steal CPU time – ‘st’ time in top
CPU consumption in Unix/Linux operating systems are studied using 8 different metrics: User CPU time, System CPU time, nice CPU time, Idle CPU time, Waiting CPU time, Hardware Interrupt CPU time, Software Interrupt CPU time, Stolen CPU time. In this article let us study about ‘Steal (or Stolen) CPU time’. What is ‘steal’ CPU time?... Continue Reading →
Software Interrupt time – ‘si’ time in top
CPU consumption in Unix/Linux operating systems are studied using 8 different metrics: User CPU time, System CPU time, nice CPU time, Idle CPU time, Waiting CPU time, Hardware Interrupt CPU time, Software Interrupt CPU time, Stolen CPU time. In this article let us study about ‘Software Interrupt CPU time’. What is Software Interrupt CPU time?... Continue Reading →
nice CPU time – ‘ni’ time in top
CPU consumption in Unix/Linux operating systems are studied using 8 different metrics: User CPU time, System CPU time, nice CPU time, Idle CPU time, Waiting CPU time, Hardware Interrupt CPU time, Software Interrupt CPU time, Stolen CPU time. In this article let us study about ‘nice CPU time’. What is ‘nice’ CPU time? To understand... Continue Reading →