[PLUG] strange system behavior - inotify problem?

Ted Mittelstaedt tedm at portlandia-it.com
Sat Dec 2 19:40:17 UTC 2023


I suspect a clue to your issue is in your post, - see the following:

https://stackoverflow.com/questions/639540/how-much-memory-can-a-32-bit-process-access-on-a-64-bit-operating-system

I suspect that somewhere in that mess you might have a program that's not 64 bit clean.

Just for grins try defining an 8GB ramdrive as your swapfile and I'll bet the freezing disappears.

Ted

-----Original Message-----
From: PLUG <plug-bounces at lists.pdxlinux.org> On Behalf Of American Citizen
Sent: Saturday, December 2, 2023 10:53 AM
To: Portland Linux/Unix Group <plug at pdxlinux.org>
Subject: [PLUG] strange system behavior - inotify problem?

Hello:

I have a very interesting problem occurring my opensuse Leap 15.5 linux system.

I am crunching number theory modules, using magma to do descents on elliptic curves. I do open a new konsole screen and do a tail on the magma results, in real time. There are 6 magma programs executing in this way at the same time.

I also have 3 monitoring programs, but they are set up as a bash script file with a while [ 1 ] loop, but each has a sleep nnn seconds at the end of the loop.

I was getting occasionally the tail warning message, no files left for tail, using polling instead.

I installed the inotify-comment bash script from the stackexchange web page https://unix.stackexchange.com/questions/15509/whos-consuming-my-inotify-resources. 
Running this script does not show anything unusual, I am only using 402 watches in 131 instances. I did up the values in the sysctl.conf file to large sizes, so I don't suspect that the problem is caused by this.

The system strangely halts the start of a new process, for up to 20 secs at a time, for example, I tried to open up a new Konsole screen and the window opens up, but then sits there for a period of time before completing the interior of the screen.

Another example, while typing this email, I made a mistake and had to back up, the moment I hit the backspace key, everything froze for about
10 secs or so, before resuming.

Third example, one of my monitoring screens suddenly went into uninterruptable mode, trying using control-C did not work, I had to terminate the Konsole screen and restart the bash script over again in a new window.

Right now I don't know quite what to do? This is slowing things way down for me, while the system seems fine, I am only using 4 gigs of the 32 gigs system RAM, so that should not be a problem.

Puzzled -

Randall




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