From mboxrd@z Thu Jan  1 00:00:00 1970
From: Eric Dumazet <eric.dumazet@gmail.com>
Subject: Re: [PATCH v7] rps: Receive Packet Steering
Date: Wed, 17 Mar 2010 16:34:44 +0100
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Cc: Changli Gao <xiaosuo@gmail.com>,
	David Miller <davem@davemloft.net>, netdev@vger.kernel.org
To: Tom Herbert <therbert@google.com>
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Le mercredi 17 mars 2010 =C3=A0 08:01 -0700, Tom Herbert a =C3=A9crit :
> 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_m=
ap
> > # 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
>=20
> 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.
>=20

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 :)