Since my upgrade from 19.04 to 19.10, I experience regular short freezes/lags on my Ubuntu system. I can see that some have similar issues (this post or that one). It is not only mouse freezes but system ones.

My computer is a DELL XPS 13 9343 (same series but different model than the first post mentioned).

I upgraded the BIOS from A13 to A20, no difference. I have 8GB of RAM and 16 of swap, with vm.swappiness=60.


$ ls -al ~/.local/share/gnome-shell/extensions
total 12
drwxrwxr-x 3 mhr mhr 4096 sept. 10 15:29 .
drwx------ 3 mhr mhr 4096 nov.  12 08:56 ..
drwxrwxr-x 4 mhr mhr 4096 sept. 10 15:29 desktop-icons@csoriano

enter image description here

EDIT 2 :

free -h
              total        used        free      shared  buff/cache   available
Mem:          7,7Gi       5,0Gi       590Mi       958Mi       2,1Gi       1,5Gi
Swap:          15Gi       404Mi        15Gi


$ cat /etc/fstab
# /etc/fstab: static file system information.
# Use 'blkid' to print the universally unique identifier for a
# device; this may be used with UUID= as a more robust way to name devices
# that works even if disks are added and removed. See fstab(5).
# <file system> <mount point>   <type>  <options>       <dump>  <pass>
# / was on /dev/sda4 during installation
UUID=33ef7645-839a-4b28-b627-e936853a7783 /               ext4    errors=remount-ro 0       1
# /boot/efi was on /dev/sda1 during installation
UUID=48E3-73DB  /boot/efi       vfat    umask=0077      0       1
# swap was on /dev/sda5 during installation
UUID=816ab8c7-f980-4e93-9908-8a9f1dc4a616 none            swap    sw              0       0


$ sudo ./magician -L
Samsung(R) SSD Magician DC Version 2.0
Copyright (C) 2015 SAMSUNG Electronics Co. Ltd. All rights reserved.
Bad argument "name", expected an absolute path in /dev/ or /sys or a unit name: Invalid argument
| Disk   | Model   | Serial  | Firmware  | Capacity | Drive  | Total Bytes |
| Number |         | Number  |           |          | Health | Written     |
No Samsung SSD found!
  • Edit your question and show me ls -al ~/.local/share/gnome-shell/extensions and screenshot(s) of the Disks app SMART Data window. 16G swap is excessive, but lets try vm.swappiness=80 and see if things improve. – heynnema Nov 11 '19 at 22:21
  • I have a Dell Venue Pro 7140 and I noticed the same thing. If you can, boot into any pre-5.2 kernel. There seems to be quite a number of issues affecting Dell machines from kernel 5.2.0 onwards. I backtracked my 19.10 from 5.3.0 to 5.0.0 and it's working brilliantly. :-) – tu-Reinstate Monica-dor duh Nov 12 '19 at 10:04
  • @heynnema here you go. It seems a bit better with vm.swappiness=80 (freezes/lags are less recurrent and long). – mhr Nov 12 '19 at 15:26
  • Thank you for the information. Is your boot disk a HDD or SSD? Edit your question and show me free -h and cat /etc/fstab. – heynnema Nov 12 '19 at 16:18
  • 1
    @mhr that only sets vm.swappiness for that boot. Please see my answer for a permanent setting method. Please remember to accept my answer if it was helpful, by clicking on the checkmark icon just to the left of my answer. You can also click the up arrow icon for me. Thanks! – heynnema Nov 18 '19 at 23:53

From the comments...

To slightly re-tune your system, we'll make adjustments to your swap, and see if that helps.

  • reduce swap from 16G to 4G

  • set vm.swappiness to 80 (60 is the default)

sudo sysctl -w vm.swappiness=80 # make more use of swap

sudo sysctl -p # use the values from the current sysctl.conf


The problem is caused by swapping and disk writes in general, prehpas due to some kernel regression. Fiddling with swap size and swappiness might help a little, but will not remove problem completely. I got rid of the freezes by downgrading to kernel 5.2.21 from https://kernel.ubuntu.com/~kernel-ppa/mainline/

I'm now running this kernel for 2 days with no problem, micro-freezes are gone and system runs very smoothly.


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