cvs commit: src/sys/netinet ip_fw_pfil.c

[Andre Oppermann]

"Christian S.J. Peron" wrote:
> 
> On Thu, Dec 09, 2004 at 04:41:47PM +0000, Gleb Smirnoff wrote:
> > glebius     2004-12-09 16:41:47 UTC
> >
> >   FreeBSD src repository
> >
> >   Modified files:
> >     sys/netinet          ip_fw_pfil.c
> >   Log:
> >   Check that DUMMYNET_LOADED before seeking dummynet m_tag.
> 
> I think Sam had some reservations about doing this before, We had some
> discussions and in the end it was pretty much concluded that since
> tags are rarely present, and m_tag_locate is only called if tags are present,
> adding this check unconditionally added a memory write and a compare
> for every packet.
> 
> This change may be a mistake unless you can prove some significant
> performance gain.

Checking for DUMMYNET_LOADED is a simple pointer compare to NULL and doesn't
add a memory write.  Not a big difference for sure but not hurting either.

-- 
Andre