Explanation of everything you can see in htop/top on Linux (2019)

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• Hacker News
• A bit silly that you can see a load average but not the amount of Watts used by your system.
  by amelius
• powertop to the rescue!

  https://github.com/fenrus75/powertop

  by roryirvine
• s/htop/btop/

  You'll be glad you did.

  by MomsAVoxell
• What's so good about btop? I personally can't stand its interface, I don't need bells and whistles in my terminal.
  by allarm
• Very interesting topic,Cool.
  by love0972

•    /*
      * kernel/sched/loadavg.c
      *
      * This file contains the magic bits required to compute the global loadavg
      * figure. Its a silly number but people think its important. We go through
      * great pains to make it work on big machines and tickless kernels.
      */
  
  

  so is it just silly numbers or important ?
  by Maksadbek
• Seems clear to me: it’s a silly number that people think is important. Like the Dow, H-index, GNP, ...
  by leephillips
• This is really good!

  I use htop often but pretty much only use it to find pid or cpu-culprits, and never really understood the rest.

  by TheChaplain
• For pid I find pgrep to be the better suited tool
  by bwnkl
• A different usage paradigm from *top that I have come to like better is to do differential ps-like reports and system-wide (like vmstat) reports which leaves everything in your terminal scrollback buffer as in: https://github.com/c-blake/procs { written in the uncommonly efficient, expressive Nim programming language }.
  by cb321
• I've had this bookmarked since 2016, and have referred to it many times over the years.
  by wyclif
• For the ones that don't know "nmon", have a look at it as well! (press "h" to see the list of available monitors - press it again to make it go away, press "q" to quit)

  https://nmon.sourceforge.io/pmwiki.php

  Especially disk throughput and I/O (keys "d" & "D") can be very useful.

  by zepearl
• very useful tool. I install it on every machine where I have control. I appreciate the "Wide" CPU usage graph, that can handle huge core counts easily
  by Zardoz84
• I know it from some AIX machines that we have at job, also topas comes to mind
  by shellwizard
• For top if you use the > character it will sort by memory usage. I use that sometimes to figure out why my host is becoming laggy. Also you'll see swapd is taking up CPU.
  by thijson
• I prefer using the more memory friendly M (uppercase) for memory and P (uppercase) for CPU
  by yomismoaqui
• Anyone else feel as if HN is healing? I hope this isn't the walking-ghost era of HN.
  by fractorial
• 3 AI related articles on the front page, but one is busting slop. I'm hopeful.
  by conqrr
• Healing by reverting to seven year old pre-slop articles :)
  by wonnage
• When I read stuff like this, I come to the realization that even after daily driving Linux for 20+ years I still barely utilize its full potential. Great article.
  by WD-42
• I appreciate the note on virtual memory not being reliable. This is what Windows task manager reports by default and it's terrible. Resident size is the most reliable metric. Anything else can be wrongfully inflated by things like harmless memory mapped files that won't actually hurt anything. eg. memory map 2GB of logfiles, it'll only be paged in if reading that portion of the logfile so isn't really using memory but users look at the processes and claim "OMG why does this app use so much memory". It doesn't. It uses very little. You're reading the memory usage wrong. Chrome actually had this problem for a while and they moved away from using memory mapped files. Not because memory mapped files are a bad thing but because users will read the memory usage and go crazy over what they see even though it's not really using that much actual physical memory.

  There's actually guides out there on the web that tell people judge usage by virtual memory allocated too :(. At least this article gets it right :).

  by AnotherGoodName
• Resident set size is not the amount of memory that the process wants, it’s how much the OS is willing to give it. So once memory pressure kicks in it stops being representative. I’ve seen this misunderstanding lead to bad decisions a few times. I even went so far to remove this value form charts because a team member was going left when he should have gone right.
  by hinkley
• If you use memory-mapped files, cached pages count towards the resident set size of your process. If you use ordinary file I/O, they don't. That behavior has amusing consequences in HPC clusters that monitor the memory usage of each job and kill them if they use more memory than they requested.
  by jltsiren
• > Resident size is the most reliable metric

  Actually, Proportional Set Size is more accurate than RSS. See: https://en.wikipedia.org/wiki/Proportional_set_size

  by d3Xt3r
• > This is what Windows task manager reports

  Just to clarify, Windows Task Manager uses Private Working Set by default for process memory usage which does NOT include shared pages with other processes such as libraries or memory mapped files (hence the name “private”). It only shows the memory that maps to privately allocated physical memory per process. It’s probably closer to Resident Set on Unix.

  You probably meant the memory usage in performance tab but I wanted to clarify in case people mistake it for all memory usage fields.

  by sedatk
• 2 Settings I change on every htop which makes a HUGE difference.

  1. I disable user threads. Those mostly just clutter up the htop view while providing no useful information.

  2. I enable the process tree view. Very frequently, where a process comes from is much more important than other information. It also lets you see and track things like a compiler process which is eating through a bunch of files.

  IMO, both these things should be the default behavior of htop.

  by cogman10
• I like the process tree view, but it stops the dynamic updates and reordering of process list.
  by zekrioca
• I've relatively recently migrated over to using btop[0], and it's the kind of modern interface, useful and informative, that I needed.

  As others mention it - it seems to shows the Watts used as well :) (and network, and GPU, and disks,....)

  [0]: https://github.com/aristocratos/btop

  by imrehg
• Same. Btop is the best
  by zackify
• Yup, btop zealot here, it even replaced iStatMenu on my brand new MacBook ..
  by MomsAVoxell