[HEADS-UP] mbuma is in the tree
Bosko Milekic
bmilekic at FreeBSD.org
Wed Jun 2 14:12:37 GMT 2004
> Bosko,
[deletia]
> are you going to convert mbuf tag allocator to UMA? Now
>tags are allocated with malloc(). AFAIK, tags are used heavily in pf,
>and forthcoming ALTQ. Moving to UMA should affect their performance
>positively.
First off, malloc() *is* UMA. With mbuma in the tree, I don't believe
we have any remaining custom-allocators in the tree.
As for what to do with m_tags, it is still unclear to me. Personally,
I'm conflicted about their use. On one hand, they offer a clean way
to attach metadata to packets, but on the other hand they are quite
expensive.
If you read the paper on mbuma, you'll notice that I point out that it
would be worth investigating whether, in scenarios where an m_tag is
ALWAYS required per packet (e.g., MAC), providing a secondary zone with
pre-allocated m_tags for packet headers might be worth it. Prior to
this work, however, I suggest we investigate the possibility of using
smaller mini-mbufs whenever clusters are used so that space wastage
is reduced.
-Bosko
More information about the freebsd-hackers
mailing list