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: Thu, 18 Mar 2010 07:20:32 +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 16:50 -0700, Tom Herbert a =C3=A9crit :
> >>
> >> # 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
> >=20
> > Alternatively, the rps_map could be specified explicitly, which wil=
l
> > allow weighting.  For example "0 0 0 0 2 10 10 10"  would select CP=
Us
> > 0, 2, 10 for the map with weights four, one, and three respectively=
=2E
> > This would go back to have sysfs files with multiple values in them=
,
> > so it might not be the right interface.
>=20
> Here is a patch for this...
>=20
> Allow specification of CPUs in rps to be done with a vector instead o=
f a bit map.  This allows relative weighting of CPUs in the map by repe=
ating ones to give higher weight.
>=20
> For example "echo 0 0 0 3 4 4 4 4 > /sys/class/net/eth0/queues/rx-0/r=
ps_cpus"
>=20
> assigns CPUs 0, 3, and 4 to the RPS mask with relative weights 3, 1, =
and 4 respectively.
>=20

Hmm...

I believe we should keep existing sysfs cpumask interface, because its
the only workable thing on a PAGE_SIZE=3D4096 machine with 4096 cpus.

strlen("0 1 2 3 4 ... 4095") =3D 19369

Using base 16 instead of base 10 -> 16111