Re: [PATCH v7] rps: Receive Packet Steering

[Eric Dumazet <eric.dumazet@gmail.com>]

Le mercredi 17 mars 2010 à 08:01 -0700, Tom Herbert a écrit :
> On Wed, Mar 17, 2010 at 7:09 AM, Eric Dumazet <eric.dumazet@gmail.com> wrote:

> > Anyway, current sysfs RPS interface exposes
> > a /sys/class/net/eth0/queues/rx-0/rps_cpus bitmap,
> >
> > I guess we could expose another file,
> > /sys/class/net/eth0/queues/rx-0/rps_map
> > to give different weight to cpus :
> >
> > echo "0 1 0 1 0 1 1 1 1 1" >/sys/class/net/eth0/queues/rx-0/rps_map
> >
> > cpu0 would get 30% of the postprocessing load, cpu1 70%
> >
> > Using /sys/class/net/eth0/queues/rx-0/rps_cpus interface would give an
> > equal weight to each cpu :
> >
> >
> > # echo "0 1 0 1 0 1 1 1 1 1" >/sys/class/net/eth0/queues/rx-0/rps_map
> > # cat /sys/class/net/eth0/queues/rx-0/rps_cpus
> > 3
> > # cat /sys/class/net/eth0/queues/rx-0/rps_map
> > 0 1 0 1 0 1 1 1 1 1
> > # echo 3 >/sys/class/net/eth0/queues/rx-0/rps_cpus
> > # cat /sys/class/net/eth0/queues/rx-0/rps_map
> > 0 1
> 
> Alternatively, the rps_map could be specified explicitly, which will
> allow weighting.  For example "0 0 0 0 2 10 10 10"  would select CPUs
> 0, 2, 10 for the map with weights four, one, and three respectively.
> This would go back to have sysfs files with multiple values in them,
> so it might not be the right interface.
> 

Well, you describe same idea... being able to do
echo "0 1 0 1 0 1 1 1 1 1" >rps_map
or
echo "0 0 0 1 1 1 1 1 1 1" >rps_map
or
echo "0 1 1 0 1 1 0 1 1 1" >rps_map

(filling the real map[] with given cpu numbers)

I was interleaving my cpus because I found it cool :)