Re: [PLUG] memory usage in Linux

On Wed, May 20, 2020, 1:29 PM Michael Lazin <microlaser@gmail.com> wrote:

Htop is a good command to get a handle on this. It is easier to read than top and gives lots of details. My experience says things like abnormal cpu or memory use should always be investigated.

On Wed, May 20, 2020, 1:17 PM Keith C. Perry via plug <plug@lists.phillylinux.org> wrote:
I just have the normal monitor applets up on my taskbar in KDE. I can watch all cores and memory utilization. When memory is tight, I can drop all caches with "echo 3 > /proc/sys/vm/drop_caches". The biggest memory issue to me is swap... and turning it off if you have enough real ram. That is done by adding "vm.swappiness = 1" to /etc/sysctl.conf and then running "sysctl -p".

Apparently, I have also have...

vm.overcommit_ratio = 30 ( not sure if that is the default)
vm.overcommit_memory = 0 (default)

which I think I added one upon a time to play around with to help prevent swapping (no, you just need the swappiness setting) and browsers (well Chrome) from being greedy by grabbing to much memory right away.

If 30 is not the default, I will that that has been working very well for me. I have a ton of stuff open right now an I'm only using about 40% of RAM. I know for a fact that previously I would have almost everything in use and certain operations my system would slow down for really didn't make sense. Now the only time that happens is with long running processes- especially storage i/o. I also never have to drop caches.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
Keith C. Perry, MS E.E.
Managing Member, DAO Technologies LLC
(O) +1.215.525.4165 x2033
(M) +1.215.432.5167
www.daotechnologies.com

From: "Eric Lucas via plug" <plug@lists.phillylinux.org>
To: "Philadelphia Linux User's Group Discussion List" <plug@lists.phillylinux.org>
Sent: Tuesday, May 19, 2020 2:35:08 PM
Subject: [PLUG] memory usage in Linux

I'm running Kubuntu 18.04 [1] on a Dell Laptop with a 2-core i7 [2] and 16 GB of RAM (the max apparently.)
I tend to leave lots of windows open on two or three of my four virtual desktops.
Sometimes things get slow (like participating in a zoom chat with a few dozen fellow homebrewers last night.)
I installed 'cockpit' to see what's up. All is okay except for RAM. It shows near 16GB of RAM used.
I seem to recall (from years ago) that Linux "hoovers up" all the RAM and then parcels it out to applications as needed.
If so, what's the point of telling me how much RAM I have used if it's always 99+%?
How do others monitor and/or manage RAM usage in Linux?

Thanks,
Eric Lucas

[1] - Yes, I should and will upgrade this week.
[2] - It was advertised as a 4-core because of hyperthreading or some other marketing B.S.
I'm still grumpy about that about 4 years later.

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___________________________________________________________________________
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General Discussion -- http://lists.phillylinux.org/mailman/listinfo/plug