Kernel preemption

mats.lindberg at se.transport.bombardier.com mats.lindberg at se.transport.bombardier.com
Mon Feb 14 09:49:06 GMT 2005


Hello,
I'm interested in using freebsd in a 'not so realtime, but...' software 
project.

In our running environment there are a 3 processes that need high 
priority.
The processes never need much cpu but they should be able to respond to 
network (tcp) activity within 10-20ms.

I have a testprogram in C that sends  ~24kB tcp-messages via a switched 
ethernet.
Sometimes there is a ~250ms delay in receiving (or sending). This could 
happen after an hour or so.

I've tried building a 5.3 system with PREEMPTION and the 4BSD Scheduler. 
It did not help.
I've tried building a 6.0 current system with PREEMPTION and the ULE 
scheduler. It did not boot.

I've tried this on a linux preemptive kernel and it works fine.

Is the PREEMPTION option applicable for my problem?
Should PREEMPTION work for the 4BSD scheduler?

Mats

_______________________________________________________________________________________________________________ 

This e-mail communication (and any attachment/s) may contain confidential 
or privileged information and is intended only for the individual(s) or 
entity named above and to others who have been specifically authorized to 
receive it. If you are not the intended recipient, please do not read, 
copy, use or disclose the contents of this communication to others. Please 
notify the sender that you have received this e-mail in error by reply 
e-mail, and delete the e-mail subsequently. 
Thank you. 
_________________________________________________________________________________________________________________ 


Ce message (ainsi que le(s) fichier/s), transmis par courriel, peut 
contenir des renseignements confidentiels ou protégés et est destiné à 
l?usage exclusif du destinataire ci-dessus. Toute autre personne est par 
les présentes avisée qu?il est strictement interdit de le diffuser, le 
distribuer ou le reproduire. Si vous l?avez reçu par inadvertance, 
veuillez nous en aviser et détruire ce message. 
Merci. 
_________________________________________________________________________________________________________________ 




_______________________________________________________________________________________________________________ 

This e-mail communication (and any attachment/s) may contain confidential 
or privileged information and is intended only for the individual(s) or 
entity named above and to others who have been specifically authorized to 
receive it. If you are not the intended recipient, please do not read, 
copy, use or disclose the contents of this communication to others. Please 
notify the sender that you have received this e-mail in error by reply 
e-mail, and delete the e-mail subsequently. 
Thank you. 
_________________________________________________________________________________________________________________ 


Ce message (ainsi que le(s) fichier/s), transmis par courriel, peut 
contenir des renseignements confidentiels ou protégés et est destiné à 
l?usage exclusif du destinataire ci-dessus. Toute autre personne est par 
les présentes avisée qu?il est strictement interdit de le diffuser, le 
distribuer ou le reproduire. Si vous l?avez reçu par inadvertance, 
veuillez nous en aviser et détruire ce message. 
Merci. 
_________________________________________________________________________________________________________________ 




More information about the freebsd-questions mailing list