Patch for 1mpps on if_em (was: FreeBSD handles leapsecondcorrectly)

Andre Oppermann andre at
Sun Jan 8 03:33:47 PST 2006

Massimo Lusetti wrote:
> On Sat, 2006-01-07 at 13:24 -0700, Scott Long wrote:
> > I'm about to release a patch to Andre that should allow if_em to fast
> > forward 1mpps or more on his hardware, using no shortcuts or hacks other
> > than the inherent shortcut that the ffwd code provides.  The approach
> > I'm taking also works on the other high performance network interfaces.
> > There is also a lot of work going on to streamline the ifnet layer that
> > will likely result in several hundred nanoseconds of latency being
> > removed from there.  I'd personally love to see DragonFly approach this
> Will all this great stuff end up in RELENG_6 branch?

Some of it but not all.  Those things which are driver optimizations and
other detail stuff will be backported.  Stuff that does architectual and
API/ABI changes will not.  We are not allowed to break the API/ABI within
a -STABLE series.

> That's very good news (TM) to hear...

Indeed.  I have tons of measurements and data from the test runs which has
to be processed.  Once that is done we can start to reach firm conclusions
and to tackle all the other items which put some breaks on the performance.


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