top is a Unix/Linux/BSD program to show what processing are running. It can show the top users of CPU or memory.

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How to understand the memory usage and load average in linux server

I am using a linux server which has 128GB of memory and 24 cores. I use top to see how much it is used. Its output is pasted at the end of the post. Here are two questions: (1) I see that each of the ...
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1answer
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Running 'top' with 'Irix mode' off in batch mode

Can anyone tell me how I can tweak the following top command so that it always runs in Solaris mode in a batch mode operation? top -d 3 -n 2 -b -p <PID> I need 'top' to output a process' CPU ...
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Linux - How can I see what's waiting for disk IO

I have a server that has a really high load. Nothing is jumping out at me in terms of CPU usage, and it's not swapping. I think it's cause some processes are waiting for disk IO, and I want to see ...
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2answers
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How is memory usage reported in Linux?

Using ps, I can see the size, the vsize (same as top's VIRT?), and the rss (same as top's RES?). (One more I see in top is SHR.) Could someone summarize for me what these different fields mean?
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Confused by CPU values in Unix 'top' command

In the screenshot below, the overall CPU is being reported as 3% but the mysqld process is reported as using 57%. Is this 57% of the overall 3% and thus mysqld is only using about 1.5% of the CPU? ...
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how do you interpret output of top?

Some things in top's output are pretty straightforward, like memory and swap usage. But load average numbers are a bit of a mystery: what do these three numbers mean? Also, what exactly is a zombie ...