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Bug#509215: marked as done ('top' doesn't report multi-core CPU usage properly w/ default kernel)

Your message dated Fri, 26 Dec 2008 17:54:25 +0100
with message-id <20081226165425.GA7184@galadriel.inutil.org>
and subject line Re: 'top' doesn't report multi-core CPU usage properly w/ default kernel
has caused the Debian Bug report #509215,
regarding 'top' doesn't report multi-core CPU usage properly w/ default kernel
to be marked as done.

This means that you claim that the problem has been dealt with.
If this is not the case it is now your responsibility to reopen the
Bug report if necessary, and/or fix the problem forthwith.

(NB: If you are a system administrator and have no idea what this
message is talking about, this may indicate a serious mail system
misconfiguration somewhere. Please contact owner@bugs.debian.org
immediately.)


-- 
509215: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=509215
Debian Bug Tracking System
Contact owner@bugs.debian.org with problems
--- Begin Message --- 
Package: kernel
Severity: normal


Hardware: Dell Optiplex
CPU: Core 2 quad
OS: Lenny - fresh install ~Dec 15th

Testing configuration and report:
I have a pthreads based scientific application that uses ~170% and 250% CPU usage when running 2 and 3 threads, respectively. This behavior has been consistent on several systems, including MacOS and a previous version of Lenny. CPU usage was measured using 'top'.

On the freshly installed Lenny, 'top' reported between 70%-105% usage for both 2 and 3 threads. The time required for the application to complete was comparable to runtimes on MacOS and a previous version of Lenny (all using the same or similar CPUs).

I compiled a new kernel (2.6.27.10), basing it the config stored in /boot, incorporating minor additional changes. Under the newly compiled kernel, 'top' appears to report correct CPU usage. Application runtime remains the same.

It apperas that 'top' is reporting incorrect CPU usage on the default kernel. It is also possible that the multi-threading doesn't speed anything up in this application (very possible) and that the default kernel wasn't properly handling the threads, whereas 'top' is OK. 


-- System Information:
Debian Release: lenny/sid
  APT prefers testing
  APT policy: (500, 'testing')
Architecture: amd64 (x86_64)

Kernel: Linux 2.6.27.10a (SMP w/4 CPU cores)
Locale: LANG=en_GB.UTF-8, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/bash

--- End Message ---
--- Begin Message --- 
Keith Godfrey wrote:
> I am no longer able to reproduce this bug. Please close it and I will assume that I was somehow doing something wrong (or the computer simply needed a reboot). If I am able to reproduce it again, I shall contact you.
> 
> Sorry about the apparent false alarm.

Thanks, closing the bug then.

Cheers,
        Moritz

--- End Message ---
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