sfbufs on amd64?

[Xin LI]

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Kevin Day wrote:
> 
> When using sendfile() on an amd64 box, are sfbufs still used/needed? The
> reason I ask:
> 
> # netstat -m
> 0/0/0 sfbufs in use (current/peak/max)
> 0 requests for sfbufs denied
> 0 requests for sfbufs delayed
> 1334122 requests for I/O initiated by sendfile
> 
> kern.ipc.nsfbufsused: 0
> kern.ipc.nsfbufspeak: 0
> kern.ipc.nsfbufs: 0
> 
> 
> Does sendfile work differently on amd64 so that sfbufs aren't needed, or
> is this a statistics issue?
> 
> This is in 7.0-RELEASE, btw.

- From FreeBSD 7.0-RELEASE, the system gets the ability to make use of
amd64-specific technique that eliminates the need of allocating sfbufs
and avoids the copying.  That's say, sendfile would work without needing
to separately allocating sfbufs and this would be much faster than the
old approach.

Cheers,
- --
Xin LI <delphij at delphij.net>	http://www.delphij.net/
FreeBSD - The Power to Serve!
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