Message: previous - next
Month: January 2013

Re: [trinity-devel] kdm_greet using lots and lots of CPU

From: "Timothy Pearson" <kb9vqf@...>
Date: Thu, 24 Jan 2013 12:38:52 -0600
> Quoth Russell Brown.....
>>3.5.13 kdm_greet eats lots of CPU.
> As a followup to my own post (bad form I know :-)....
> I've made a change to kdm that adds an option 'UseKDMCTL' (like UseSAK)
> in kdmrc that can turn off the monitoring of the kdmctl FIFO (defaults
> to true so it won't change anything).
> Turning off this monitoring (and thence the loop where Tim's 500usec
> sleep was inserted to try and reduce the load) drops the CPU usage of
> idle kdm_greet processes from significant to undetectable (as background
> I'm trying to configure a 30+ Xterminal system and having 30 kdm_greets
> trying to eat ~10% CPU each isn't good).

Thank you for tracing the problem.  Given the high CPU load observed I
probably have no choice but to rework the SAK pipe code in tdm to use a
TQSocketNotifier to avoid busywaiting.  Opening a bug report on this issue
would help us track the problem and any potential fixes that are committed
to GIT; you can also attach your patch to the new bug report.