Merge branch 'virtio_net-Expand-affinity-to-arbitrary-numbers-of-cpu-and-vq'

Merge branch 'virtio_net-Expand-affinity-to-arbitrary-numbers-of-cpu-and-vq'

Caleb Raitto says:

====================
virtio_net: Expand affinity to arbitrary numbers of cpu and vq

Virtio-net tries to pin each virtual queue rx and tx interrupt to a cpu if
there are as many queues as cpus.

Expand this heuristic to configure a reasonable affinity setting also
when the number of cpus != the number of virtual queues.

Patch 1 allows vqs to take an affinity mask with more than 1 cpu.
Patch 2 generalizes the algorithm in virtnet_set_affinity beyond
the case where #cpus == #vqs.

v2 changes:
Renamed "virtio_net: Make vp_set_vq_affinity() take a mask." to
"virtio: Make vp_set_vq_affinity() take a mask."

Tested:

[InstanceSetup]
set_multiqueue = false

$ cd /proc/irq
$ for i in `seq 24 60` ; do sudo grep ".*" $i/smp_affinity_list;  done
0-15
0
0
1
1
2
2
3
3
4
4
5
5
6
6
7
7
8
8
9
9
10
10
11
11
12
12
13
13
14
14
15
15
0-15
0-15
0-15
0-15

$ cd /sys/class/net/eth0/queues/
$ for i in `seq 0 15` ; do sudo grep ".*" tx-$i/xps_cpus; done
0001
0002
0004
0008
0010
0020
0040
0080
0100
0200
0400
0800
1000
2000
4000
8000

$ sudo ethtool -L eth0 combined 15

$ cd /proc/irq
$ for i in `seq 24 60` ; do sudo grep ".*" $i/smp_affinity_list;  done
0-15
0-1
0-1
2
2
3
3
4
4
5
5
6
6
7
7
8
8
9
9
10
10
11
11
12
12
13
13
14
14
15
15
15
15
0-15
0-15
0-15
0-15

$ cd /sys/class/net/eth0/queues/
$ for i in `seq 0 14` ; do sudo grep ".*" tx-$i/xps_cpus; done
0003
0004
0008
0010
0020
0040
0080
0100
0200
0400
0800
1000
2000
4000
8000

$ sudo ethtool -L eth0 combined 8

$ cd /proc/irq
$ for i in `seq 24 60` ; do sudo grep ".*" $i/smp_affinity_list;  done
0-15
0-1
0-1
2-3
2-3
4-5
4-5
6-7
6-7
8-9
8-9
10-11
10-11
12-13
12-13
14-15
14-15
9
9
10
10
11
11
12
12
13
13
14
14
15
15
15
15
0-15
0-15
0-15
0-15

$ cd /sys/class/net/eth0/queues/
$ for i in `seq 0 7` ; do sudo grep ".*" tx-$i/xps_cpus; done
0003
000c
0030
00c0
0300
0c00
3000
c000

$ sudo ethtool -L eth0 combined 16
$ sudo sh -c "echo 0 > /sys/devices/system/cpu/cpu15/online"

$ cd /proc/irq
$ for i in `seq 24 60` ; do sudo grep ".*" $i/smp_affinity_list;  done
0-15
0
0
1
1
2
2
3
3
4
4
5
5
6
6
7
7
8
8
9
9
10
10
11
11
12
12
13
13
14
14
0
0
0-15
0-15
0-15
0-15

$ cd /sys/class/net/eth0/queues/
$ for i in `seq 0 15` ; do sudo grep ".*" tx-$i/xps_cpus; done
0001
0002
0004
0008
0010
0020
0040
0080
0100
0200
0400
0800
1000
2000
4000
0001

$ for i in `seq 8 15`; \
do sudo sh -c "echo 0 > /sys/devices/system/cpu/cpu$i/online"; done

$ cd /proc/irq
$ for i in `seq 24 60` ; do sudo grep ".*" $i/smp_affinity_list;  done
0-15
0
0
1
1
2
2
3
3
4
4
5
5
6
6
7
7
0
0
1
1
2
2
3
3
4
4
5
5
6
6
7
7
0-15
0-15
0-15
0-15

$ cd /sys/class/net/eth0/queues/
$ for i in `seq 0 15` ; do sudo grep ".*" tx-$i/xps_cpus; done
0001
0002
0004
0008
0010
0020
0040
0080
0001
0002
0004
0008
0010
0020
0040
0080
====================

Signed-off-by: David S. Miller <davem@davemloft.net>