How to Interpret Load Average in Linux (Linux Crash Course Series)
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- Опубліковано 17 чер 2024
- The "Load Average" within our Linux servers and workstations enables administrators to understand how well the system is keeping up with its workload. By reading the values within the Load Average, we can also determine the overall performance of the system over several time periods, which will give us an idea on how the workloads are progressing. In this video, Jay will teach you how to fetch the current load average, and how to read the values.
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Time Codes
00:00 - Intro
00:51 - Get your very own Linux server with Linode (sponsor) f learnlinux.link/akamai
02:20 - Which command(s) can you use to find the load average?
04:10 - Understanding what the three load average values represent
05:18 - Determining how many CPUs your server or workstation has
07:22 - What constitutes a high load average?
10:39 - Which load average period should you pay the most attention to?
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#LinuxTutorial #LoadAverage #Linux - Наука та технологія
I liked your grocery store analogy. When I worked in customer support (defect support for a large commercial software product), we had spikes in activity (incoming customer calls) occasionally, but we were able to eventually catch up while the incoming volume was lower/more normal. Over time, the number of incoming calls increased (in part due to the, uh... evolving quality of the product and new releases, as well as increasing numbers of customers), and the "spikes" started to become the new "normal" volume. Unfortunately, management was very slow at hiring new people, so we got more and more overwhelmed, as our load average grew ever higher. Eventually people started leaving (CPU cores burning out? 😁 ), which made the load even higher on the remaining people.
I've since moved on to other things, and I'm enjoying my work a lot more than I did when I was in that job. I do credit it for helping me to get into my later positions, though.
Anyway, just wanted to say I did like your analogy, I thought it illustrates the concept well. I've been using Linux for 24 years now, and I knew a higher load average is "bad", or at least hints at a potentially overloaded system, but I always got confused about how to actually interpret it. I guess the idea that "1 means 100%" comes from the days of single-core systems. This video definitely helped me to understand what's really going on.
This video helped me understand linux load average concept very well. Thanks!
The number of processors can also be found by the command " nproc " which can be installed be various packages, eg coreutils
I ordered a hard copy of your book last night. Keep up the good work, sir.
I see @abu bua mentioned "nproc" as an alternate for processor info.
"lscpu" can be used as well. It is usualy installed on most Linux distros, but can be installed as part of the "util-linux" package if not on your system.
Thank you Jay... Awesome information. I have learned 80% of my Linux commands from watching your videos and reading comments.
This is the Best Video on this Topic! Thank you again for awesome videos!
From my experience, the load average also starts to grow when RAM runs out and processes start to eat into the swap file, which affects disk IO
Awesome video, i liked the simple way you explained the topic
👍👍👍👍👍
Thank you very much Jay, learnt something New & Useful today😊
clear and nice as always
Great video, thank you!
Great work 🥳🥳🥳 Thank you 💜💜💜
Really helpful video!!!
Thank you very much for detailed explanation, just to add on we can use nproc command to find number of processors
Great video. Have not understood this
You’re right. The supermarket analogy worked
Love the supermarket analogy
平衡 ... mmm... you really nailed it.
really interesting, thanks ...
شكرا Thanks it was very helpful
Thanks for the video, it's awesome! A question! how did you make your BASH CLI so nice? what did you use? Thanks!
Thank you.
Awesome as always Jay - Is it the number of CPUs or Cores that has to be reached in the load average for it to be 100% used. I noticed you said 2 for your example but your cpuinfo shows that you have a multicore system. Thanks!
The percentage analogy is ALWAYS a bad one, when looking at load average. It is the average number of processes queued to be handled by cpu package, over a given length of time(1, 5 and 15 minutes as you mentioned). This is distinctly different from determining capacity, because it is NOT how many processes actually handled over that time. Only how many are queued for cpu, over that time. A load avg of 4 on a quad core cpu, doesn't mean the cpu is at 100% capacity. The way processes are managed in the kernel, means linux can adequately manage a number of processes well over the number of cpu cores. To know if the load is high, takes a much more holistic approach to troubleshooting, involving consideration of CPU states.
good video
@Jay Just wanted to say you a great job with these vids Jay.
And I also wanted to put a comment down just in case it truly does help with the algorithm stuff and your channel being promoted/recommended by GoogleTube..
Hey Jay! Have you tried the system 76 darter pro recently? I ask because I just purchased one and wanted to know your thoughts on it.
I think load average is not only measured by CPU workload. It can also increase when there is a disk I/O bottleneck. I usually encounter very high load averages during specific backup jobs of folders with many small files from mechanical drives while the actual CPU utilization is below 30%.
Thats how I understand it. The more processes waiting to be completed the higher the load. Any sort of bottleneck should increase load avg
I've been doing some performance testing over the past week and you can get load averages that exceed the number of cpus. So loads above 100 percent by this measurement. I believe load avg is determined by the number of processes waiting to be completed so it shouldn't exceed number of cpus when working normally. But when ur slamming the system and there's serious bottlenecking that's not necessarily the case. The highest I saw was loads of around 3 on 2 cores (when I started seeing loads above 100 percent I got kinda interested and tried to see how high it could get). Ultimately load avg was more determined by the network interface on the machines than the cpus they had.
Testing was done on pfsense firewalls and I was trying to see how low power consumption could be pushed without affecting performance. Firewalls are on all the time and spend a lot of that time at very low load if ur not servicing users at all hours.
Correct, the load average can go above the number of CPUs. I’ve seen it go to 500 and higher, to the point where the CPU is so pegged it can’t even authenticate an SSH session so you can even connect to it and fix it.
@@LearnLinuxTV I still think the 100 percent measurement is useful. As I understand it it's at that point that users will start noticing and making calls to IT
Nice analogy. BTW why not use the following one liner instead of scrolling up and down in /proc/cpuinfo:
cat /proc/cpuinfo | grep -i 'cpu cores'
Cool
Do those numbers still apply when using a virtual machine?
👍👍
One can also run nproc to find out number of cores they have.
If you run 'grep -c "processor" /proc/cpuinfo' it will return the number of logical CPUs
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If you know how to use pipe and grep this will help to see how many CPU more easily:
cat /proc/cpuinfo | grep processor
grep -c processor /proc/cpuinfo
Why, if you're running a 32-core EPYC CPU, did /proc/cpuinfo show 'cpu cores: 1" ? That makes no sense to me. For this VM, you have at least 2 cores. Shouldn't it say 2 or 32?
nproc: this simple command tells you how many processor your machine has.
how does load average calculated？ when my load average is 12 and I have 8 cpu corea， my android phone is not janky.
i have 2 cores and 2 threads per core so it makes 4 CPUs , so I have 4 CPUs , so does that mean i have 4 cores or 4 threads , and if it will have 4 threads then why are you saying you have 2 cores because youe have 1 core and 2 threads so that makes it 2 CPUs.
So please explain this ?
Wait a min, you have 48 Cores for Desktop and calculations based on load average based with CPU... ok, Overkill. The load then, will never reach 48.0 unless it's trying to compile, maybe the Linux kernel 48 times at 1 go [maybe the only way to know is to try it] Peace :-)
Once again I wasted my time on you. And you didn't even mention how disk handling affects this parameter.