Thanks for the great analysis. I&#39;ve updated pmon.py (r10575), as I agree that that loop can run slower.  What was the CPU usage before that?<br><br>You previously mentioned getting some numbers on rospy -- I&#39;d love to know if you see any issues there or not, even if you don&#39;t have time to track down more fast loops. AFAIK, the main problem with rospy is that Python gobbles up memory when you use threads, and rospy is a bit too greedy in this regard. The hope is to redo the threading model in a future rewrite, but it&#39;s good to understand the current issues when prioritizing.<br>

<br>thanks<br>Ken<br><br><div class="gmail_quote">On Sat, Jul 31, 2010 at 11:28 AM, Cedric Pradalier <span dir="ltr">&lt;<a href="mailto:cedric.pradalier@mavt.ethz.ch">cedric.pradalier@mavt.ethz.ch</a>&gt;</span> wrote:<br>

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On 07/31/10 13:11, Cedric Pradalier wrote:
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  <br>
To continue on my fight against overhead, I&#39;ve had good performance
improvement of rosout by replacing all the timeout argument in the
CallbackQueue::callAvailable and CallbackQueue::callOne from 0.01s to
0.1s. <br>
Now my rosout is really sitting in a corner doing nothing while I&#39;m not
logging.<br>
  <br>
Can you foresee any drawbacks from this change?<br>
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And the final touch to make roscore behave: in package roslaunch, file
src/roslaunch/pmon.py:570<br>
replacing time.sleep(0.01) with time.sleep(0.1) makes roscore use less
than 1% cpu, and AFAICS just slows down a little the process respawn
mechanism.<br>
<br>
I don&#39;t think I will optimise farther for now. In summary, applying all
the changes in this thread brings my set of core processes (roscore,
rosmaster, rosout, some serial data gatherer/publisher) from a total of
20% cpu load, to 5-6%, without any noticeable performance loss so far.<br>
<br>
HTH<div class="im"><br>
<br>
<pre cols="80">-- 
Dr. Cedric Pradalier
<a href="http://www.asl.ethz.ch/people/cedricp" target="_blank">http://www.asl.ethz.ch/people/cedricp</a>
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