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Sometimes we're going to need

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to get informations about our specific CPU,

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so the best thing to do is we can use less command,

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we're going to use a proc folder.

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We're going to do cpuinfo.

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Now this screen gives us a lot of good information

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about the type of processors that we're using.

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It identifies the number of processors

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that we're referring to.

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'Cause sometimes we might be in a situation

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where we have multiple processors.

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And we can see some good information here.

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Of course, cache size.

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We can also see the cpu cores,

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the amount of cores associated with this CPU.

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We can see speed with the cpu MHz,

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how fast it should be performing.

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And again, this is going to help us do some research,

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so when we start looking at more detailed information,

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we can get a good gauge

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on how fast should our CPU be running,

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which will determine how fast our system can operate.

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Another command we're going to like to use is called uptime.

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The most important part of this information

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is going to be the load average.

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The first field is for a one-minute increment.

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The second field is for five-minute increments.

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And the third field is for 15-minute increments.

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Now what this tells us is the average amount of processes

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that are being active or waiting to be used

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in that timeframe.

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So for example, for one minute, on average for that CPU,

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it's only taking 0.08 percentage/usage capacity

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for that CPU.

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And the same thing for the five-minute increment

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and the 15-minute increment.

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Now of course, the first field that we see

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all the way to the left, it just lets us know how long

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has the system been up from the very beginning,

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since this last reboot.

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The next command we would like to be familiar with

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is the sar command.

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It lets us see a breakdown

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of a lot of different information.

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This report consists of various sections,

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each of which consists of the type of data

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at the time it was collected.

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The default mode of the sar command displays the CPU usage

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in various time increments for each category of resource

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that access the CPU, such as users, the system,

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input/output scheduling, etcetera.

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And what's here at the bottom of the report,

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this is the average of all the information

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compiled together.

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Now another way we can format this sar command

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is we can use these two options.

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And what those two options determine is every 2 seconds,

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it's going to give us a total of 6 queries.

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So again, as you see like the last screen,

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it was kind of a lot of information all at once,

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but now we can kind of see things as they're happening,

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which will further help us isolate CPU performance issues.

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Now also with the sar, we can use this S option.

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It's going to give us swap space information.

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Now swap space is going to be key

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when you're dealing with systems that have low RAM usage

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because it's going to use the physical memory

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in order to offload some of that processes

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that the RAM's typically using.

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But we see here in my system,

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I'm not using much CPU speed, I'm only running the shell.

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So it's not going to be cause for too much concern.

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But when you're using a server

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that's really dealing with a lot of requests simultaneously,

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you might see the swap space used a certain period of time.

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Another good place to find information about your memory

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is going to be in that proc folder again.

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This time it's going to be under meminfo.

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And we went through multiple ways to check our memory.

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And I think at this point we can all agree

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that memory is vital to performance of any type of system,

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especially when it comes to servers.

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All right, now another way to quickly look at memory

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is the free command.

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It just gives us a quick view of what's free

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in our RAM and also in our swap memory.

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And of course, whenever we need a human-readable format,

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it helps us see a little bit better

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by converting things to megabytes and gigabytes,

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things that we're used to using

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when we're reading information and reports.

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And also if we're looking for a specific type of things,

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we can just set it up for megabytes

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and probably even gigabytes if we wanted to.

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Again, all these things are just for formatting the report,

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and the human-readable is probably going to be

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the most commonly used and most useful option for us.

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And one of the final commands we're going to go over

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is the vmstat command.

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So what that does is, again, we can use the same options

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that we use for the sar command.

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Pretty much what that does is it allows us

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to tell the system, "Hey, every 5 seconds

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we want 3 queries total."

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Because when you typically use the vmstat command,

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it only displays the last information

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from the most recent reboot.

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So this is going to give us a good look into what's going on.

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And this is just without the option.

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And we could also use the same command,

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but we're going to use a d option.

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And it helps us determine the information per device.

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So now it helps us isolate which partitions

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are using the most memory.

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Thank you for sticking with me with this walkthrough,

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and I'll see you in the next lesson.