Unexplained performance loss [SOLVED I THINK!]

jesnow · l33t Joined: 26 Apr 2006 Posts: 856

Stop snickering.

My gentoo machine slows to a crawl after a few days, it takes seconds to open a window. An eternity to close a tab on chromium. Stopping and restarting the browser helps a little. It's an i7, not a slow machine, 12GB RAM. The load is not high, the machine is not paging or out of memory ... just ... slow. Ordinary web pages like this one can't keep up with my typing.

Then if I restart KDE, all the performance comes back. The resource hogs I use are chromium and libreoffice, but I can't tell where the poor performance is coming from. At least when I'm running an emerge -e world, I can exactly see what's making my machine slow.

It's puzzling.

Is it possible somebody's mining bitcoin using javascript on my browser? Would that not show up on my load meter? some other kind of skullduggery?

Any helpful thoughts greatly appreciated.

Jesnow

frebrd · n00b Joined: 26 Feb 2018 Posts: 3

jesnow,

Few ideas:

1. performance can also be impacted by I/O, if you are using a HDD. Maybe Nepomuk, Strigi, Baloo and Akonadi are doing their thing? try disabling them if they are enabled. Also put your /tmp folder on tmpfs

2. What addons do you have installed on chromium? ublock and umatrix should block any unwanted javascript. Have you tried firefox?

3. (Unlikely for basic tasks) Is your cpu thermal throttling?

4. Have you tried using performance governor?

mike155 · Posted: Tue Feb 27, 2018 8:33 am Post subject:

Use top and iotop to find out which process(es) consume CPU time or I/O bandwidth.

Juippisi · Developer Joined: 30 Sep 2005 Posts: 724 Location: /home

Im having similar problems with Gnome3. If its up for 3 days, the UI gets laggy and every operation takes a long time. Relogging solves the problem.

I have 16 GB of memory and a powerful i7 processor so I doubt that's the problem. I did install iotop to monitor HDD activity next time (Im using SSD), so thanks for that tip. I do have htop installed and nothing is using memory or CPU a lot there.

Ive just pretty much lived with the problem. I used to believe its somehow NVIDIA-related because if I, say watch a twitch stream with mpv for 12 hours then Gnome starts feeling laggy earlier than 3 days uptime.

NeddySeagoon · Posted: Wed Feb 28, 2018 9:41 am Post subject:

jesnow,

Check your kernel.
$ grep COMPACT /usr/src/linux/.config
CONFIG_COMPACTION=y

Without that, it gets harder and harder for the kernel to dynamically allocate RAM.
It will page, by dropping code and reloading it, when that happens. That's slow, even on SSD.
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dantrell · l33t Joined: 01 Jun 2007 Posts: 915 Location: Earth

Juippisi · Developer Joined: 30 Sep 2005 Posts: 724 Location: /home

The Doctor · Moderator Joined: 27 Jul 2010 Posts: 2678

I'd say that reflects on the quality of the development of the respective desktops. Memory leaks are the likely cause and those are likely from the innocent looking and easily forgotten desktop.
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krinn · Watchman Joined: 02 May 2003 Posts: 7470

Saw this kind of strange slowness one day : cpu not busy, ram all happy, but dns resolving was bad, and everything that was trying to resolve dns was having bad day trying server1, timeout, server2 timeout...

Just in case it help you, maybe you have the same case, someone after a few days change dns settings (dhcp or whatever network manager) and kde/gnome whatever DE do have a lot of name resolution to do and is slow waiting for an answer while it takes no cpu or ram.

jesnow · l33t Joined: 26 Apr 2006 Posts: 856

I was just looping back to say I found the problem in the dns performance. And guess what (see below)...

It's interesting that there is no benchmark I can find for dns performance, but it is now integral to every aspect of our existence. It was slowing down local "file save" dialogs, for example! Libreoffice internal operation slowed to a crawl. Text in Kwrite would wait several seconds to post. All because of a slow dns server. Seems like a pretty dramatic point of failure for all linux systems, and very hard to debug!

Jon.

Hu · Moderator Joined: 06 Mar 2007 Posts: 21635

Local file save dialogs should not be using DNS at all. If they are, somebody did something wrong.

How did you determine it to be caused by DNS? Were you using a self-hosted DNS server, one provided by your organization, by your ISP, or a generic Internet DNS server?

pjp · Administrator Joined: 16 Apr 2002 Posts: 20067

This is not a new problem and it is not unique to KDE. It has been around since at least 2002:

2006: Extremely Poor GNOME perf. due to slow net speed [Solved]
2002: kde slow, check out my /etc/hostname /etc/hosts
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krinn · Watchman Joined: 02 May 2003 Posts: 7470

pallaert · n00b Joined: 29 Apr 2005 Posts: 26

Experiencing the same thing since a few days.

Using KDE & Chromium. For sure, this is related to chromium which shows an insane usage of GPU usage in Chromium's own process manager. However, when freezing happens, it's not just chrome, it's really everything!

I've seen a couple of X-related packages upgraded recently, I have the impression it's since I upgraded them.

Visiting some websites like https://giphy.com, with log of graphics, animation, it makes the problem very reproducible.

I had a www-client/chromium 64.xxx and have upgraded to 65.0.3325.146, unfortunately, upgrading didn't solve the issue.

I doubt it could be DNS related as that might indeed be source of slowness, but normally, not freezing all apps.
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Hu · Moderator Joined: 06 Mar 2007 Posts: 21635

The original poster traced his problem to DNS. If you are confident that your problem is not DNS related, then you do not have the same problem. If you need help with a different problem, you should open a separate thread for it, since this problem has a solution and has been marked as solved, which tends to reduce traffic.

Juippisi · Developer Joined: 30 Sep 2005 Posts: 724 Location: /home

https://www.omgubuntu.co.uk/2018/03/gnome-shell-has-a-memory-leak-and-it-might-not-be-fixed-for-ubuntu-18-04-lts I think this might be it for me.

sQu1rr · n00b Joined: 26 Jan 2014 Posts: 24 Location: UK

sQu1rr · n00b Joined: 26 Jan 2014 Posts: 24 Location: UK

Has anyone solved it?

krinn · Watchman Joined: 02 May 2003 Posts: 7470

jesnow · l33t Joined: 26 Apr 2006 Posts: 856

I noticed the worst slowdown was while running Libroffice along with chrome. which I do all the time. shut down LO, and chrome is back to normal. So I tracked it down to the Java runtime environment: Switch off the JRE and LO runs a million times faster and so does everything else. It was literally to the point where libroffce would leave a trail of windows across the screen when moving or resizing, and I could easilt get ahead of the typing buffer (!) when writing something like this post and have the text appears several seconds later.

turn off the JRE and it's not exactly snappy like it should be for a core i7 but much better.

JS.