tcp_output starving -- is due to mbuf get delay?

Terry Lambert tlambert2 at
Thu Apr 10 15:25:41 PDT 2003

Petri Helenius wrote:
> There was a discussion on mballoc performance on freebsd-net about a month ago
> but it has since died without conclusion.

Actually, a researcher at UKY implemented an alternate allocator
using an explicit freelist and mp_machdep.c tricks, rather than
using the zone/slab/uma stuff, and obtained a significant speedup.
Yes, I was involved in suggesting implementation details.  The
resulting code is not SMP-safe, however, unless you are willing
to use a global freelist (obviously).

BTW: The zone allocator *still* calcualtes some values each time
it goes back to the system for more pages, that it should precalculate
and cache instead.

-- Terry

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