Re: High CPU usage applet
Op vrijdag 08-05-2009 om 00:40 uur [tijdzone -0400], schreef Timo Sirainen: > Somewhat relevant, yes, but I think people talking in that page don't > understand correctly the root cause of the problem. Linux scheduler is > good enough nowadays that even lots of processes all eating 100% CPU > don't make the system unusable. The problem comes from when some > process eats all the memory and starts forcing other processes to swap. That's not the only reason why your system might get sluggish. > I just tested this actually. I created 100 processes running an > infinite loop, causing the system load on a 2 core machine to hit 100. > It was a bit sluggish, but still perfectly usable. Try adding one of the following in a (tight) infinite loops: * some disk (or similar) I/O, syncing very often (doing lots of small database inserts & commits might be a good example) * an expensive syscall, preferably one that locks out the other processes wanting to access the same kernel/system resource Now try again... ;) -- Jan Claeys -- Ubuntu-devel-discuss mailing list Ubuntu-devel-discuss@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-devel-discuss
Re: High CPU usage applet
Am 08.05.2009 um 14:47 schrieb Andrew Sayers: > [...] then send a STOP signal to processes guilty beyond a > reasonable doubt, before asking the user what to do. Please ask the user first. There are very valid reasons why a system is running under full steam. For example, if one makes actually use of the available processing power: Doing scientific calculations, rendering videos, playing games, serving. Markus - - - - - - - - - - - - - - - - - - - Dipl. Ing. Markus Hitter http://www.jump-ing.de/ -- Ubuntu-devel-discuss mailing list Ubuntu-devel-discuss@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-devel-discuss
Re: High CPU usage applet
Hi, do you know the hardware-monitor applet? I've extended this applet to have exactly this feature. It shows in the tooltip processes which consume lot's of cpu or memory ressources. But because I'm not a gnome/gtk programmer I couldn't get "kill" buttons into the tooltip. If you are interested I can post the patched version of this applet. But this applet still has one problem: It fails to run/compile on Jaunty because of depencies to old libs. But if you use Intrepid you will have no problems. Cheers, Martin Am Freitag, den 08.05.2009, 13:47 +0100 schrieb Andrew Sayers: > I think this is a really good idea. Making it an applet would let you > list "suspects" (programs that have a high CPU load, or use a lot of > memory, etc.), then send a STOP signal to processes guilty beyond a > reasonable doubt, before asking the user what to do. > > I once played around with a command-line program that looked for > applications that were page-faulting like it was going out of style, by > repeatedly reading /proc/[0-9]*/stat. If you're interested in pursuing > this idea yourself, I'd be happy to send along the (C++) code I wrote > back then. > > - Andrew > -- Ubuntu-devel-discuss mailing list Ubuntu-devel-discuss@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-devel-discuss
Re: High CPU usage applet (how to use apport to report CPU hogs)
Timo Sirainen wrote: > If some process has been eating 100% CPU for hours, there should be some > kind of a notification that it's happening. Like a small icon could > appear to gnome panel and clicking it would show the process details and > allow to kill it. > > Nowadays with multicore processors this 100% CPU usage can be difficult > to notice. I've had it happen several times and lasting for over a week > until I finally realized the system is running slower than normal. > > (I know about the existing system monitor applet. I don't want a > distracting animation on my screen.) > > Great idea, here is another proposed solution that utilizes apport as well. I have been in this position as well, I have quad core machine with 8gb RAM and I had just re-installed it so I did not have the CPU meter added as a GNOME applet yet. I had this machine in this state for almost a week before I finally added the CPU metering applet and saw it. Once 8-core becomes the norm I don't even think the "CPU status graph tools" we have today will be enough because I'm very much used to xorg and what not taking up like 1-5% of my CPU all the time when I'm working on stuff so if one core out of eight is maxed out that means the graphing tool showing like 10% all over CPU load which is a bit of a distortion of the real situation I'd say. Problems get's even worse with 16 cores etc. I think an appropriate solution would be to force each app to tag itself with a "LICENSED_TO_HOG_THE_CPU" badge before it starts to hog the CPU with 100% intensity for extended periods of time. Once we have a way for apps to tell us "yes i'm hogging the CPU by design" we can just fire up an apport dialog asking the user if he wants to report the CPU hogging as a bug to LP. If some apps gets incorrectly reported we'll just fix that by making sure that they activate the "LICENSED_TO_HOG_THE_CPU" badge/tag before they hog CPU and that they remove the marker/tag when they stop their CPU intensive run. Clearly some processes like "s...@home" or whatever should be allowed to always be marked with the LICENSED_TO_HOG_THE_CPU tag but normal apps should only mark themselves with the tag for short periods of time while they know that they will (or might) hog the CPU for a valid reason. For example, if apt needs to rebuild some package database or whatever, then that process should mark itself with the tag, do the necessary computations and then unmark itself. Of course the apport thing won't trigger until a process runs with 100% CPU for like 60 full seconds without having the LICENSED_TO_HOG_THE_CPU marker, and because of this most apps will never need any changes at all. And if too many changes in too many apps are needed, one option would be to invert the meaning of the marker so that certain processes gets marked with a tag that means THIS_PROCESS_MAY_NOT_USE_100_CPU_FOR_LONGER_THAN_10_SECS or similar. I'd love to have such a tag on pulseaudio for example which runs into CPU spins every now and then and never for valid reasons. I actually think a system like this could undercover a range of interesting bugs and performance problems. Martin -- Ubuntu-devel-discuss mailing list Ubuntu-devel-discuss@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-devel-discuss
Re: High CPU usage applet
I think this is a really good idea. Making it an applet would let you list "suspects" (programs that have a high CPU load, or use a lot of memory, etc.), then send a STOP signal to processes guilty beyond a reasonable doubt, before asking the user what to do. I once played around with a command-line program that looked for applications that were page-faulting like it was going out of style, by repeatedly reading /proc/[0-9]*/stat. If you're interested in pursuing this idea yourself, I'd be happy to send along the (C++) code I wrote back then. - Andrew -- Ubuntu-devel-discuss mailing list Ubuntu-devel-discuss@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-devel-discuss
Re: High CPU usage applet
Mackenzie Morgan wrote: > On Friday 08 May 2009 12:40:04 am Timo Sirainen wrote: >> Somewhat relevant, yes, but I think people talking in that page don't >> understand correctly the root cause of the problem. Linux scheduler is >> good enough nowadays that even lots of processes all eating 100% CPU >> don't make the system unusable. The problem comes from when some >> process eats all the memory and starts forcing other processes to swap. >> >> I just tested this actually. I created 100 processes running an >> infinite loop, causing the system load on a 2 core machine to hit 100. >> It was a bit sluggish, but still perfectly usable. > > Quick question: > On a dual-core machine, does 100% CPU mean 100% of *both* cores or 100% of > one > and 0% of the other? > > I'm pretty sure I've seen top report 105% for a process before, so I thought > 100% on a dual core was really only half of the processing power. It depends on how you measure it (and different applications report it differently), but yes, on a multicore machine, a single-threaded runaway process consumes only a portion of the available CPU. It still costs heat and power and component failure rate. A multithreaded application with multiple runaway threads can consume all available CPU power, but this is usually noticable, and the user will do something. It's the case of the runaway process that consumes a sufficiently small proportion of resources that the user continues to operate blissfully unaware of the situation that would be good to monitor and report. There exist cases where this is desired (e.g. long compilation, data analysis, etc.), in which case the user can choose to do nothing. In other cases, where it's not desired, the user could get a longer battery life, or improved machine health, or just a snappier response. In cases where this is a result of the Ubuntu code, and represents a fixable bug, notification to the user could result in better bug reports, and a better chance of fixing things. -- Emmet HIKORY -- Ubuntu-devel-discuss mailing list Ubuntu-devel-discuss@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-devel-discuss
Re: High CPU usage applet
On Friday 08 May 2009 12:40:04 am Timo Sirainen wrote: > Somewhat relevant, yes, but I think people talking in that page don't > understand correctly the root cause of the problem. Linux scheduler is > good enough nowadays that even lots of processes all eating 100% CPU > don't make the system unusable. The problem comes from when some > process eats all the memory and starts forcing other processes to swap. > > I just tested this actually. I created 100 processes running an > infinite loop, causing the system load on a 2 core machine to hit 100. > It was a bit sluggish, but still perfectly usable. Quick question: On a dual-core machine, does 100% CPU mean 100% of *both* cores or 100% of one and 0% of the other? I'm pretty sure I've seen top report 105% for a process before, so I thought 100% on a dual core was really only half of the processing power. -- Mackenzie Morgan http://ubuntulinuxtipstricks.blogspot.com apt-get moo signature.asc Description: This is a digitally signed message part. -- Ubuntu-devel-discuss mailing list Ubuntu-devel-discuss@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-devel-discuss
Re: High CPU usage applet
On May 7, 2009, at 10:35 PM, John McCabe-Dansted wrote: > On Fri, May 8, 2009 at 8:51 AM, Timo Sirainen wrote: > If some process has been eating 100% CPU for hours, there should be > some > kind of a notification that it's happening. Like a small icon could > appear to gnome panel and clicking it would show the process details > and > allow to kill it. > > The following are relevant to this discussion > http://brainstorm.ubuntu.com/idea/11628 (similar idea) Somewhat relevant, yes, but I think people talking in that page don't understand correctly the root cause of the problem. Linux scheduler is good enough nowadays that even lots of processes all eating 100% CPU don't make the system unusable. The problem comes from when some process eats all the memory and starts forcing other processes to swap. I just tested this actually. I created 100 processes running an infinite loop, causing the system load on a 2 core machine to hit 100. It was a bit sluggish, but still perfectly usable. -- Ubuntu-devel-discuss mailing list Ubuntu-devel-discuss@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-devel-discuss
Re: High CPU usage applet
On Fri, May 8, 2009 at 8:51 AM, Timo Sirainen wrote: > If some process has been eating 100% CPU for hours, there should be some > kind of a notification that it's happening. Like a small icon could > appear to gnome panel and clicking it would show the process details and > allow to kill it. The following are relevant to this discussion http://brainstorm.ubuntu.com/idea/11628 (similar idea) http://docs.kde.org/kde3/en/kdebase/kicker/naughty-applet.html (for KDE) -- John C. McCabe-Dansted PhD Student University of Western Australia -- Ubuntu-devel-discuss mailing list Ubuntu-devel-discuss@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-devel-discuss
