Re: [LAD] PCI MIDI jitter - comparison Ubuntu (bad) and Suse (might be ok)

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To: <linux-audio-dev@...>
Date: Sunday, July 11, 2010 - 3:11 pm

Hi Ralf,

You are comparing a banana and an orange to find out which one is
sweeter. Given the nature of the problem it would help a lot to have as
little differences between the systems under test, otherwise it's
impossible to track it down.

I hazard a guess that it's Ubuntu's 2.6.32 realtime-preemt-kernel.
There are no official 2.6.32 rt-patches and it's likely that some of the
back/forward ports have screwed things up.

Is 'cat /proc/interrupts' identical on both systems?
what about 'ps ax | wc -l' and
'ps -eo pid,class,rtprio,ni,pri,pcpu,stat,comm --sort -rtprio'
Are there high-priority jobs present on Ubuntu which are not on SuSE?

What happens if you use the same kernel (SuSE's kernel on Ubuntu, or
vice versa) but different disto user-lands? Is there still a difference
in your measurements?


On 07/11/2010 04:53 PM, Ralf Mardorf wrote:

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Re: [LAD] PCI MIDI jitter - comparison Ubuntu (bad) and Suse..., Robin Gareus, (Sun Jul 11, 3:11 pm)