Kirspel, Kevin Kevin-Kirspel at
Fri Jun 30 11:48:39 UTC 2017

I'm not sure but I'll look into it today.  I'll need to quantify each callout handler's processing time to see which one is causing the problem.  I know the USB and Ethernet stacks/drivers use callouts but maybe there is something else.

Kevin Kirspel
Electrical Engineer - Sr. Staff
Idexx Roswell
235 Hembree Park Drive
Roswell GA 30076
Tel: (770)-510-4444 ext. 81642
Direct: (770)-688-1642
Fax: (770)-510-4445

-----Original Message-----
From: devel [mailto:devel-bounces at] On Behalf Of Sebastian Huber
Sent: Friday, June 30, 2017 1:15 AM
To: devel at
Subject: Re: LIBBSD

On 29/06/17 20:02, Kirspel, Kevin wrote:

> For those who run a RTEMS 4.12 single processor application with 
> LIBBSD, what percentage of time does your application spend in the 
> timer server task?  My NXP LPC3250 application spends about 13% of the 
> processor time processing the timer server.  Most of that time is 
> spent processing LIBBSD's kernel callouts.  I am wondering if there is 
> an advantage to only call the FreeBSD's callout_process() function 
> when we know a callout needs to be processed.  This would reduce the 
> number of RTEMS timer fires (which currently fire every tick).

Normally, the timer server should be in the range of 0.x% of CPU time. 
If you have 13%, then you have a lot of timeout processing. What is the reason for this?

Sebastian Huber, embedded brains GmbH

Address : Dornierstr. 4, D-82178 Puchheim, Germany
Phone   : +49 89 189 47 41-16
Fax     : +49 89 189 47 41-09
E-Mail  : sebastian.huber at
PGP     : Public key available on request.

Diese Nachricht ist keine geschäftliche Mitteilung im Sinne des EHUG.

devel mailing list
devel at 

More information about the devel mailing list