Messages in this thread |  | | Date | Wed, 22 May 1996 10:46:23 +0100 | From | Pedro Roque Marques <> | Subject | Re: Proposal: merged system calls |
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>>>>> "Warner" == Warner Losh <imp@village.org> writes:
Warner> : Makes you wonder why everyone bases their stuff on the Warner> berkeley stack, : it sucks rocks from a performance Warner> standpoint, and the speed problems : are inherent in it's Warner> overall design and structure (read this as: mbufs : are Warner> fundamentally flawed)... but we have some buglets left in Warner> our : stuff so maybe I should cut myself short right here Warner> ;)
Warner> While there are bugs in the now current linux code, there Warner> are some big names that trashed mbufs. Van Jacobson has a Warner> BSD based stack that he's heavily hacked to *NOT* use Warner> mbufs, but a scheme that escapes me at the moment.
He called them pbufs. They are continuous memory buffers that are alocated by devices on input... now, this model seams familiar doesn't, it ? ;-)
Warner> He also did the hyperoptimizations of the checksum Warner> calculations for the m68k (I believe).
Warner> Why do people like them? mbufs are good enough to get Warner> decent performance on most available hardware and they are
The big reason for mbufs is that they were the best choice for Vax systems with very little memory... Today we can afford to use contiguous buffers and the traffic patterns and network speeds have increased greatly. Mbufs are a dead end...
Warner> in a stack that is relatively solid. The linux crowd Warner> knows well the pitfalls of trying to reinvent the TCP Warner> wheel :-).
As knows well the pitfalls in using BSD TCP... BSD 4.4 is a solid TCP implementation but as known pitfalls and it will need replacement some time in the future. The Linux crowd is well positioned in that race...
Don't take this as the Not Ivented Here Syndrome... We do take a lot of concepts invented on BSD but we do try to build our network stack because there are things we think we should do different. This is a big win to both free software and networking.
regards, Pedro.
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