Date: Mon, 14 Feb 2005 10:51:13 +0100 From: mats.lindberg@se.transport.bombardier.com To: freebsd-questions@freebsd.org Subject: Kernel preemption Message-ID: <OF796D306A.AA481924-ONC1256FA8.00348AC1-C1256FA8.0035F36B@UK.BOMBARDIER.TRANSPORT.COM>
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Hello, I'm interested in using freebsd in a 'not so realtime, but...' software=20 project. In our running environment there are a 3 processes that need high=20 priority. The processes never need much cpu but they should be able to respond to=20 network (tcp) activity within 10-20ms. I have a testprogram in C that sends ~24kB tcp-messages via a switched=20 ethernet. Sometimes there is a ~250ms delay in receiving (or sending). This could=20 happen after an hour or so. I've tried building a 5.3 system with PREEMPTION and the 4BSD Scheduler.=20 It did not help. I've tried building a 6.0 current system with PREEMPTION and the ULE=20 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 =5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F= =5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F= =5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F= =5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F= =5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=20 This e-mail communication (and any attachment/s) may contain confidential=20 or privileged information and is intended only for the individual(s) or=20 entity named above and to others who have been specifically authorized to=20 receive it. If you are not the intended recipient, please do not read,=20 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=20 e-mail, and delete the e-mail subsequently.=20 Thank you.=20 =5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F= =5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F= =5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F= =5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F= =5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=20 Ce message (ainsi que le(s) fichier/s), transmis par courriel, peut=20 contenir des renseignements confidentiels ou prot=E9g=E9s et est destin=E9 = =E0=20 l?usage exclusif du destinataire ci-dessus. Toute autre personne est par=20 les pr=E9sentes avis=E9e qu?il est strictement interdit de le diffuser, le = distribuer ou le reproduire. Si vous l?avez re=E7u par inadvertance,=20 veuillez nous en aviser et d=E9truire ce message.=20 Merci.=20 =5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F= =5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F= =5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F= =5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F= =5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=20 =5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F= =5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F= =5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F= =5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F= =5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=20 This e-mail communication (and any attachment/s) may contain confidential=20 or privileged information and is intended only for the individual(s) or=20 entity named above and to others who have been specifically authorized to=20 receive it. If you are not the intended recipient, please do not read,=20 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=20 e-mail, and delete the e-mail subsequently.=20 Thank you.=20 =5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F= =5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F= =5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F= =5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F= =5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=20 Ce message (ainsi que le(s) fichier/s), transmis par courriel, peut=20 contenir des renseignements confidentiels ou prot=E9g=E9s et est destin=E9 = =E0=20 l?usage exclusif du destinataire ci-dessus. Toute autre personne est par=20 les pr=E9sentes avis=E9e qu?il est strictement interdit de le diffuser, le = distribuer ou le reproduire. Si vous l?avez re=E7u par inadvertance,=20 veuillez nous en aviser et d=E9truire ce message.=20 Merci.=20 =5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F= =5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F= =5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F= =5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F= =5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=20
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