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Neil Youngman [ny at youngman.org.uk]
Would anyone care to hazard a guess why top is claiming that the top 3 process are between them using 480% CPU on a dual core box?
Neil
Ben Okopnik [ben at linuxgazette.net]
On Mon, Oct 22, 2007 at 01:07:52PM +0100, Neil Youngman wrote:
> Would anyone care to hazard a guess why top is claiming that the top 3 process > are between them using 480% CPU on a dual core box?
In my experience, 'top' sometimes goes off into lulu land and claims silly crap. For some reason - I recall that someone explained it to me once, but I've lost the index to the brain cells containing the explanation - it has a problem with some processes (e.g. XFree86) which do some strange thing that 'top' can't cope with - so it just lies.
In other words, put not your complete trust in the reports of 'top'; 'tis a weak reed.
A prudent navigator will never limit himself to a single method, particularly one requiring ... a device that is subject to mechanical damage or loss. -- Nathaniel Bowditch, compiler of the first American compendium on navigation
It would be interesting to go through all the possible combinations of the three processes (if possible) to get a better handle on what triggers it, though.
Does the machine actually bog when you see this report, or is it just showing this stuff without any external effect?
-- * Ben Okopnik * Editor-in-Chief, Linux Gazette * https://LinuxGazette.NET *
Neil Youngman [Neil.Youngman at youngman.org.uk]
On Monday 22 October 2007 18:09, Ben Okopnik wrote:
> It would be interesting to go through all the possible combinations of > the three processes (if possible) to get a better handle on what > triggers it, though.
They're all running today and top is behaving perfectly normally. I did observe that pressing 'I' changed the output, so that 480% became more like 250%. This seems to be an "Irix mode" toggle and I have no idea why it should make any difference. Also I see little point in choosing between 2 different values of wrong, unless it offers any further clues.
> Does the machine actually bog when you see this report, or is it just > showing this stuff without any external effect?
No, they were all 'nice 19' processes, BOINC clients and the like, and the system was coping just fine.
Neil
Karl-Heinz Herrmann [khh at khherrmann.de]
On Tue, 23 Oct 2007 13:27:44 +0100 Neil Youngman <Neil.Youngman at youngman.org.uk> wrote:
> observe that pressing 'I' changed the output, so that 480% became > more like 250%. This seems to be an "Irix mode" toggle and I have no > idea why it should
Maybe you could also try to press "1" -- then all CPUs will be shown individually.
K.-H.
Neil Youngman [Neil.Youngman at youngman.org.uk]
On Tuesday 23 October 2007 22:26, Karl-Heinz Herrmann wrote:
> On Tue, 23 Oct 2007 13:27:44 +0100 > > Neil Youngman <Neil.Youngman at youngman.org.uk> wrote: > > observe that pressing 'I' changed the output, so that 480% became > > more like 250%. This seems to be an "Irix mode" toggle and I have no > > idea why it should > > Maybe you could also try to press "1" -- then all CPUs will be shown > individually.
Yeah, that showed individual CPU stats which were phone, but the process stats were still garbage.
Neil
Jim Jackson [jj at franjam.org.uk]
On Wed, 24 Oct 2007, Neil Youngman wrote:
> On Tuesday 23 October 2007 22:26, Karl-Heinz Herrmann wrote: > > On Tue, 23 Oct 2007 13:27:44 +0100 > > > > Neil Youngman <Neil.Youngman at youngman.org.uk> wrote: > > > observe that pressing 'I' changed the output, so that 480% became > > > more like 250%. This seems to be an "Irix mode" toggle and I have no > > > idea why it should > > > > Maybe you could also try to press "1" -- then all CPUs will be shown > > individually. > > Yeah, that showed individual CPU stats which were phone, but the process stats > were still garbage.
I recall a thread on lkml prompted by bizarre TOP figures.
https://lkml.org/lkml/2007/10/3/123
this contribution seems to imply there were problems with dual core AMD64 see...
https://lkml.org/lkml/2007/10/3/276
but there were other issues around an actual kernel bug.
A change of kernel may get rid of the problem?