Contributed by jose on from the faster-faster-FASTER dept.
"Heavily loaded network servers can experience resource exhaustion. At best, resource exhaustion will slow server response, but left uncorrected, it can result in a crash of the server.The paper is available (PS) from the OpenBSD website. PB and Henning will be at Fosdem this weekend, one of the larger and more popular Open Source meetings in Europe. Damn, we need a budget so I can attend and report on the event.This paper by Philipp Buhler and Henning Brauer provides an understanding of the memory management of OpenBSD, how to monitor the current status of the system, why crashes occur and how to prevent them. Read more at http://www.bsdforums.org/forums/showthread.php?threadid=6640 ."
UPDATE : "Slide's are up here ," said Phillip.
(Comments are closed)
By Anonymous Coward () on
budget my butt :P
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By schubert () on
By TZ8 () on
tz8
By Philipp () pb@ on mailto:pb@
in pf(4)
it just got commited, so it should be
"pretty soon" on the webserver, check
http://www.openbsd.org/events.html
for the upcoming mirroring
By Philipp () pb@ on http://www.openbsd.org/papers/fosdem2k3-pf.mgp
http://www.openbsd.org/papers/fosdem2k3-pf.mgp
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By Anonymous Coward () on
By Anonymous Coward () on
Regardless, it is the first decent writeup for OpenBSD performance tuning I've yet seen. Thanks to the authors for writing it (and OBSDJ for linking to it).
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By Meoa () on
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By Anonymous Coward () on
This is a really rare occassion: PPPoE (who uses this?) and high speed PPPoE (for most ADSL connection OpenBSD userland pppoe will be enough).
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By Anonymous Coward () on
i know he did it later blah blah blah
By RabidCow () on
By Henning Brauer () henning@openbsd.org on mailto:henning@openbsd.org
you might know network data is traversing through the system in so-called mbufs, memory buffers of a fixed size - 256 bytes if memory serves me right. lots of them linked together (linked list) represent a packet then. As most stuff the kernel needs to do with network data only needs access to the header data and this is completely withing the first mbuf usually, that is very efficient.
HOWEVER, the payload may be bigger, and it would be very inefficient to split it into 265 bytes chunks. That's why mbuf clusters exist, which are bigger - 2048 bytes if memory serves me right, and the mbufs only contain a reference to the mbuf cluster then.
keep in mind this memory space is only needed as long as the network data is travelling through the system. once it is send out on some NIC or written to some socket where some deamon is listening, or dropped for whatever reason, the mbufs and mbuf clusters occupied by the packet are freed. if they are not freed then we have a mbuf leak, just like the one I fixed some days ago ;-)
thus, the amount of NMBCLUSTERS you need is usually _very_ small.
I have exactly 3 machines out of 60 or so that need increased NMBCLUSTERS...
oh, and the mbuf(9) manpage is a very good read on that.
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By Anonymous Coward () on
By Anonymous Coward () on
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By Motley Fool () motleyfool@dawgstar.org on mailto:motleyfool@dawgstar.org