GNOME Bugzilla – Bug 313001
gnome-system-monitor does not sort correctly, or does not show all tasks
Last modified: 2012-12-31 07:58:39 UTC
For a long time (as long as I remember using gtop), not all processes seem to be shown, even if "All Processes" is selected. In particular, if you have one process that's taking 100% CPU, it sometimes does not show up in the list. I have attached some screenshots to illustrate the problem. I don't know if this is a bug in libgtop or in gtop, or maybe I'm missing something. The CPU usage applet and the CPU usage graph of gtop both show 100% CPU utilization. Regular top shows that in the screenshots, acroread is the culprit. However acroread does not show in the gtop list, and the highest-CPU item takes 1%. All processes are viewed. Am I doing something wrong? I have seen this across many versions of gtop/libgtop, and have never found how to show the "invisible" processes. BTW in this scenario, Acroread was running fine, and still responding to user input. It just seemed to be spinning in one of its threads. I'm marking this major since there is no way to kill the process from libgtop, since you can't even see it! And joe blogs user doesn't necessarily know how to start top or use the kill cmd.
Created attachment 50462 [details] Screenshot 1 Screenshot showing top and gtop -- there is no "acroread" in gtop. Also, X does not show up. Acroread is making X take CPU time.
Created attachment 50463 [details] Screenshot 2 Screenshot showing that gtop's "Resources" tab (as well as the system info applet's CPU usage stats, first graph of four at the top) shows CPU is at 100%.
look at the vertical scrollbar on Screenshot 1 ...
:-) oops... Still, I always have processes sorted in order of CPU usage. The reason I filed the bug is because when I first brought up gtop, there was nothing at the top of the list showing with anything over 0% CPU usage. I therefore sorted the list by process name to look for acroread (it wasn't even on the list), then re-sorted by CPU, then, to make sure that I wasn't reverse-sorting by CPU (so 0% was at the top), I tried sorting forward/reverse a couple of times (everything was still showing 0%). Finally I tried dragging around the terminal window on top of Screenshot #1 to verify that at least Nautilus went up to 1% when it had to do some redrawing, and it was indeed sorted higher than the rest of the tasks at 0%, so I knew I had CPU usage sorted in reverse-numerical order. At some point in all that column sorting/reverse-sorting, the scrollbar must have changed. Still, as I mentioned above, acroread wasn't even on the list. If nobody else has seen this though, I will close and re-open when I have a screenshot with the scrollbar at the top, to prove I'm not crazy :o) Thanks...
BTW 100% CPU tasks almost always show up in gtop, it's just that several times I've seen that they haven't. I've never been able to figure out what the difference is. Thanks..
gnome-system-monitor version ?
$ rpm -q gnome-system-monitor libgtop2 gnome-system-monitor-2.11.90-1 libgtop2-2.11.90-1 However I have seen this sporadically (every month or two) across several GNOME releases.
"when I first brought up gtop, there was nothing at the top of the list showing with anything over 0% CPU usage." this ?
I'm not sure I understand your question, but I think you are asking if I took the screenshot when I first brought up gtop. No I didn't, I took the screenshot after hunting for the acroread process, and after sorting in different ways, hence the change in scrollbars before I took the screenshot. I did forget to scroll to the top before taking the screenshot, sorry.
OK, I have more screenshots, this time with the scrollbar in the right position :o) First screenshot: Look at gnome-system-monitor, top, and CPU usage applet. CPU usage is at 100%. Yet gnome-system-monitor shows the highest-CPU app as itself, at 3%. Note the sorting is by decreasing CPU usage, and "All processes" are shown. top shows NetworkManager and dbus-daemon as together taking up close to 100%, but they are not at the top of the list. Second screenshot: I'm not sure what happened here, but I just sorted by name (to try to see if NetworkManager was in the list, and it was), then by CPU again. NetworkManager was now at the top of the list, but dbus-daemon was still not shown. I may have selected NetworkManager or something before re-sorting by CPU, and I didn't check to see if dbus-daemon was on the list too (I didn't think of doing that). Process dependencies were not shown. It is possible the sort order is messed up by the logic that allows you to show process dependencies, even when dependencies are not shown. (Or something like that.)
Created attachment 54856 [details] First screenshot referenced in the previous comment
Created attachment 54857 [details] Second screenshot referenced in the above comment
If you display the cpu time column, is it coherent with top ?
Yes, it is exactly consistent right now, but the problem I have described in this bug is not 100% reproducible (in fact it's something like 5%-reproducible!) so I don't know if the two will always be consistent.
Are you sure it's not because top and system-monitor don't refresh at the same frequence and at the same time ?
Yes. I am talking about situations where there is exactly one CPU-bound task, when re-sorting by CPU usage doesn't list the task at the top, even after waiting for a few seconds.
I also have noticed gnome-system-monitor not displaying some processes. I will notice my system monitor panel applet displaying 100% CPU utilisation, but when I open gnome-system-monitor no processes are displayed that have a high CPU%. I then check top, and top does display the process I'm looking for. I reported the bug on Launchpad viewable here: https://bugs.launchpad.net/ubuntu/+source/gnome-system-monitor/+bug/346806
I still see this on 2.28. It may at least in part be due to Bug 507108, but I'd swear that sometimes processes are just not shown on the list at all -- running top alongside gnome-system-monitor and sorting and re-sorting a column still fails to show all the high-%CPU tasks.
Thanks for taking the time to report this bug. However, you are using a version that is too old and not supported anymore. GNOME developers are no longer working on that version, so unfortunately there will not be any bug fixes for the version that you use. By upgrading to a newer version of GNOME you could receive bug fixes and new functionality. You may need to upgrade your Linux distribution to obtain a newer version of GNOME. Please feel free to reopen this bug if the problem still occurs with a newer version of GNOME.