kvm_read() vs ioctl performance

Poul-Henning Kamp phk at phk.freebsd.dk
Sat Mar 22 06:02:04 PDT 2008

In message <523743.91444.qm at web63914.mail.re1.yahoo.com>, Barney Cordoba writes

>Is this a page of memory, or some other "page"

Yes, chunks of 4K (usually).

>concept? As I mentioned, there are n  structures, and
>there could be 20K or more of them. The structures are
>72 bytes. Its also read-only, and not dreadfully
>important that the stats are exactly tied to a precise
>moment in time.

The point about shared memory is that there are no system
calls involved, so they are for all pratical points of
view free.

Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.

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