You are here: Home / Science / RTLWS Submitted Papers / 
2020-01-29 - 07:06
Details of the Real Time Linux Foundation Working Group Project

OSADL Project: Real Time Linux Workshops

Real Time Linux Foundation Workshops since 1999

Real Time Linux Workshops

1999 - 2000 - 2001 - 2002 - 2003 - 2004 - 2005 - 2006 - 2007 - 2008 - 2009 - 2010 - 2011 - 2012 - 2013 - 2014 - 2015

Twelfth Real-Time Linux Workshop on October 25 to 27, in Nairobi, Kenya

The basis for Real-Time Ethernet protocols in Linux

Thomas Gleixner and Sebastian Siewior, Linutronix GmbH, Germany

Even if the latest PREEMPT_RT patched Linux kernel is used, the network stack can inflict unbound latencies on real-time Ethernet protocols due to:

  • Socket buffer allocations
  • Traffic congestion with non real-time traffic

In a proof-of-concept implementation, the following mechanisms are used
to overcome the above limitations:

  • Generic preallocated socket buffer pools
  • Protocol-specific traffic policing and traffic shaping

This approach is minimally invasive to the network stack and has zero impact when the real-time protocol related functions are not enabled:

  • Network card drivers require no or minimal changes to support preallocated buffer pools
  • Traffic control is modular and only loaded and enabled when required
  • No restriction on network tools and network functionality

The paper does not cover the complex user space part of real-time Ethernet protocols.