Process & threads - Karmic vs past kernels
tim.gardner at canonical.com
Fri Mar 12 14:34:36 UTC 2010
On 03/12/2010 07:17 AM, Peter Matulis wrote:
> Chase Douglas wrote:
>> On Wed, Mar 10, 2010 at 3:45 PM, Peter Matulis
>> <peter.matulis at canonical.com> wrote:
>>> Can anyone tell me whether the Karmic kernel has implemented a different
>>> way of what it considers a process (as opposed to threads)?
>>> I have a situation where CPU load is zero on Karmic but considerably
>>> higher in Jaunty and earlier.
>>> The scenario is a single java process with many threads. The system has
>>> 4 cores and only one java process should logically produce a negligible
>>> CPU load but why was this not the case with earlier kernels? Has
>>> something changed in Karmic that would explain what I'm seeing?
>> I doubt that to be the case. Have you been able to get more data for
>> your bug ?
>>  https://bugs.launchpad.net/ubuntu/+source/linux/+bug/513848
> Yes, but I couldn't get as much CPU usage out of the Karmic test. My
> 'top' results show the following:
> Cpu1 : 0.3%us, 0.6%sy
> Cpu2 : 2.4%us, 0.6%sy
> Cpu3 : 9.1%us, 1.8%sy
> Cpu4 : 16.0%us, 7.4%sy
> With a load of 0.00 across the board.
> Now since CPU1 has such a low usage it makes sense that load is
> negligible since that CPU is always available. It seems that the
> question is now:
> Why the CPU usage is so much different between Karmic and Jaunty in this
> (single process/multiple thread) scenario.
There was a pretty major change in the process and I/O schedulers
between Jaunty and Karmic. Lucid is different yet again.
Tim Gardner tim.gardner at canonical.com
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