Re: [patch] Real-Time Preemption, -VP-2.6.9-rc4-mm1-U0

[Robert Wisniewski <bob@watson.ibm.com>]

Lee Revell writes:
 > On Thu, 2004-10-14 at 22:00, Robert Wisniewski wrote:
 > > Theoretically a problem, in practice not, i.e., good enough for soft/normal
 > > real-time, not hard real-time; probably wouldn't want my heart monitor on
 > > it, but then I wouldn't be using Linux for that either :-)
 > 
 > Also, the issue here is how we do debug logging.  You would presumably
 > not use this at all in production.
 > 
 > Lee 

Yes actually you would.  If the tracing subsystem is designed correctly you
leave it in for production systems and enable it when you need to find a
problem.  The reason is because many times you can not reproduce a problem
someone in production is seeing in your environment.  In addition to the
LTT/Relayfs and K42 tracing work, lots of of tracing work/papers suggest
leaving it in all the time.  Most commercial operating systems have made
the investment to correctly design tracing facilities so they are
available.  LTT in combination with relayfs could fulfill that role for
Linux.

Robert Wisniewski
The K42 MP OS Project
Advanced Operating Systems
Scalable Parallel Systems
IBM T.J. Watson Research Center
914-945-3181
http://www.research.ibm.com/K42/
bob@watson.ibm.com