[PATCH v2 net-next 0/2] virtio_net: Expand affinity to arbitrary numbers of cpu and vq

[PATCH v2 net-next 0/2] virtio_net: Expand affinity to arbitrary numbers of cpu and vq

[Caleb Raitto]

From: Caleb Raitto <caraitto@google.com>

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:

# 16 vCPU, 16 queue pairs, Debian 9 recent net-next kernel, GCE

# Disable GCE scripts setting affinities during startup.
#
# Add the following to
# /etc/default/instance_configs.cfg.template and reboot:
[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

# 16 vCPU, 15 queue pairs
$ 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

# 16 vCPU, 8 queue pairs
$ 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

# 15 vCPU, 16 queue pairs
$ 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

# 8 vCPU, 16 queue pairs
$ 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

Caleb Raitto (2):
  virtio: Make vp_set_vq_affinity() take a mask.
  virtio_net: Stripe queue affinities across cores.

 drivers/crypto/virtio/virtio_crypto_core.c |  4 +-
 drivers/net/virtio_net.c                   | 46 ++++++++++++++--------
 drivers/virtio/virtio_pci_common.c         |  7 ++--
 drivers/virtio/virtio_pci_common.h         |  2 +-
 include/linux/virtio_config.h              |  7 ++--
 5 files changed, 39 insertions(+), 27 deletions(-)

-- 
2.18.0.597.ga71716f1ad-goog

[PATCH net-next 1/2] virtio: Make vp_set_vq_affinity() take a mask.

[Caleb Raitto]

From: Caleb Raitto <caraitto@google.com>

Make vp_set_vq_affinity() take a cpumask instead of taking a single CPU.

If there are fewer queues than cores, queue affinity should be able to
map to multiple cores.

Link: https://patchwork.ozlabs.org/patch/948149/
Suggested-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Caleb Raitto <caraitto@google.com>
---
 drivers/crypto/virtio/virtio_crypto_core.c | 4 ++--
 drivers/net/virtio_net.c                   | 8 ++++----
 drivers/virtio/virtio_pci_common.c         | 7 +++----
 drivers/virtio/virtio_pci_common.h         | 2 +-
 include/linux/virtio_config.h              | 7 ++++---
 5 files changed, 14 insertions(+), 14 deletions(-)

diff --git a/drivers/crypto/virtio/virtio_crypto_core.c b/drivers/crypto/virtio/virtio_crypto_core.c
index 83326986c113..7c7198553699 100644
--- a/drivers/crypto/virtio/virtio_crypto_core.c
+++ b/drivers/crypto/virtio/virtio_crypto_core.c
@@ -146,7 +146,7 @@ static void virtcrypto_clean_affinity(struct virtio_crypto *vi, long hcpu)
 
 	if (vi->affinity_hint_set) {
 		for (i = 0; i < vi->max_data_queues; i++)
-			virtqueue_set_affinity(vi->data_vq[i].vq, -1);
+			virtqueue_set_affinity(vi->data_vq[i].vq, NULL);
 
 		vi->affinity_hint_set = false;
 	}
@@ -173,7 +173,7 @@ static void virtcrypto_set_affinity(struct virtio_crypto *vcrypto)
 	 *
 	 */
 	for_each_online_cpu(cpu) {
-		virtqueue_set_affinity(vcrypto->data_vq[i].vq, cpu);
+		virtqueue_set_affinity(vcrypto->data_vq[i].vq, cpumask_of(cpu));
 		if (++i >= vcrypto->max_data_queues)
 			break;
 	}
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 39a7f4452587..43fabc0eb4d2 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -1878,8 +1878,8 @@ static void virtnet_clean_affinity(struct virtnet_info *vi, long hcpu)
 
 	if (vi->affinity_hint_set) {
 		for (i = 0; i < vi->max_queue_pairs; i++) {
-			virtqueue_set_affinity(vi->rq[i].vq, -1);
-			virtqueue_set_affinity(vi->sq[i].vq, -1);
+			virtqueue_set_affinity(vi->rq[i].vq, NULL);
+			virtqueue_set_affinity(vi->sq[i].vq, NULL);
 		}
 
 		vi->affinity_hint_set = false;
@@ -1905,8 +1905,8 @@ static void virtnet_set_affinity(struct virtnet_info *vi)
 	for_each_online_cpu(cpu) {
 		const unsigned long *mask = cpumask_bits(cpumask_of(cpu));
 
-		virtqueue_set_affinity(vi->rq[i].vq, cpu);
-		virtqueue_set_affinity(vi->sq[i].vq, cpu);
+		virtqueue_set_affinity(vi->rq[i].vq, cpumask_of(cpu));
+		virtqueue_set_affinity(vi->sq[i].vq, cpumask_of(cpu));
 		__netif_set_xps_queue(vi->dev, mask, i, false);
 		i++;
 	}
diff --git a/drivers/virtio/virtio_pci_common.c b/drivers/virtio/virtio_pci_common.c
index 705aebd74e56..465a6f5142cc 100644
--- a/drivers/virtio/virtio_pci_common.c
+++ b/drivers/virtio/virtio_pci_common.c
@@ -421,7 +421,7 @@ const char *vp_bus_name(struct virtio_device *vdev)
  * - OR over all affinities for shared MSI
  * - ignore the affinity request if we're using INTX
  */
-int vp_set_vq_affinity(struct virtqueue *vq, int cpu)
+int vp_set_vq_affinity(struct virtqueue *vq, const struct cpumask *cpu_mask)
 {
 	struct virtio_device *vdev = vq->vdev;
 	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
@@ -435,11 +435,10 @@ int vp_set_vq_affinity(struct virtqueue *vq, int cpu)
 	if (vp_dev->msix_enabled) {
 		mask = vp_dev->msix_affinity_masks[info->msix_vector];
 		irq = pci_irq_vector(vp_dev->pci_dev, info->msix_vector);
-		if (cpu == -1)
+		if (!cpu_mask)
 			irq_set_affinity_hint(irq, NULL);
 		else {
-			cpumask_clear(mask);
-			cpumask_set_cpu(cpu, mask);
+			cpumask_copy(mask, cpu_mask);
 			irq_set_affinity_hint(irq, mask);
 		}
 	}
diff --git a/drivers/virtio/virtio_pci_common.h b/drivers/virtio/virtio_pci_common.h
index 135ee3cf7175..02271002c2f3 100644
--- a/drivers/virtio/virtio_pci_common.h
+++ b/drivers/virtio/virtio_pci_common.h
@@ -141,7 +141,7 @@ const char *vp_bus_name(struct virtio_device *vdev);
  * - OR over all affinities for shared MSI
  * - ignore the affinity request if we're using INTX
  */
-int vp_set_vq_affinity(struct virtqueue *vq, int cpu);
+int vp_set_vq_affinity(struct virtqueue *vq, const struct cpumask *cpu_mask);
 
 const struct cpumask *vp_get_vq_affinity(struct virtio_device *vdev, int index);
 
diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h
index 5559a2d31c46..32baf8e26735 100644
--- a/include/linux/virtio_config.h
+++ b/include/linux/virtio_config.h
@@ -79,7 +79,8 @@ struct virtio_config_ops {
 	u64 (*get_features)(struct virtio_device *vdev);
 	int (*finalize_features)(struct virtio_device *vdev);
 	const char *(*bus_name)(struct virtio_device *vdev);
-	int (*set_vq_affinity)(struct virtqueue *vq, int cpu);
+	int (*set_vq_affinity)(struct virtqueue *vq,
+			       const struct cpumask *cpu_mask);
 	const struct cpumask *(*get_vq_affinity)(struct virtio_device *vdev,
 			int index);
 };
@@ -236,11 +237,11 @@ const char *virtio_bus_name(struct virtio_device *vdev)
  *
  */
 static inline
-int virtqueue_set_affinity(struct virtqueue *vq, int cpu)
+int virtqueue_set_affinity(struct virtqueue *vq, const struct cpumask *cpu_mask)
 {
 	struct virtio_device *vdev = vq->vdev;
 	if (vdev->config->set_vq_affinity)
-		return vdev->config->set_vq_affinity(vq, cpu);
+		return vdev->config->set_vq_affinity(vq, cpu_mask);
 	return 0;
 }
 
-- 
2.18.0.597.ga71716f1ad-goog

RE: [PATCH net-next 1/2] virtio: Make vp_set_vq_affinity() take a mask.

[Gonglei (Arei)]

> -----Original Message-----
> From: linux-crypto-owner@vger.kernel.org
> [mailto:linux-crypto-owner@vger.kernel.org] On Behalf Of Caleb Raitto
> Sent: Friday, August 10, 2018 9:18 AM
> To: herbert@gondor.apana.org.au; mst@redhat.com; davem@davemloft.net
> Cc: Gonglei (Arei) <arei.gonglei@huawei.com>; jasowang@redhat.com;
> netdev@vger.kernel.org; linux-crypto@vger.kernel.org; Caleb Raitto
> <caraitto@google.com>
> Subject: [PATCH net-next 1/2] virtio: Make vp_set_vq_affinity() take a mask.
> 
> From: Caleb Raitto <caraitto@google.com>
> 
> Make vp_set_vq_affinity() take a cpumask instead of taking a single CPU.
> 
> If there are fewer queues than cores, queue affinity should be able to
> map to multiple cores.
> 
> Link: https://patchwork.ozlabs.org/patch/948149/
> Suggested-by: Willem de Bruijn <willemb@google.com>
> Signed-off-by: Caleb Raitto <caraitto@google.com>
> ---
>  drivers/crypto/virtio/virtio_crypto_core.c | 4 ++--
>  drivers/net/virtio_net.c                   | 8 ++++----
>  drivers/virtio/virtio_pci_common.c         | 7 +++----
>  drivers/virtio/virtio_pci_common.h         | 2 +-
>  include/linux/virtio_config.h              | 7 ++++---
>  5 files changed, 14 insertions(+), 14 deletions(-)
> 

Acked-by: Gonglei <arei.gonglei@huawei.com>

Re: [PATCH v2 net-next 0/2] virtio_net: Expand affinity to arbitrary numbers of cpu and vq

[David Miller]

From: Caleb Raitto <caleb.raitto@gmail.com>
Date: Thu,  9 Aug 2018 18:18:27 -0700

> 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:
 ...

Yes, this is so much better than the NAPI module parameter thing!

I'll apply this, and we can adjust/tweak the logic if necessary
on top of these changes.

Thanks!

Re: [PATCH v2 net-next 0/2] virtio_net: Expand affinity to arbitrary numbers of cpu and vq

[Michael S. Tsirkin]

On Thu, Aug 09, 2018 at 06:18:27PM -0700, Caleb Raitto wrote:
> From: Caleb Raitto <caraitto@google.com>
> 
> 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.

Acked-by: Michael S. Tsirkin <mst@redhat.com>

Let's see where does it take us.

> v2 changes:
> Renamed "virtio_net: Make vp_set_vq_affinity() take a mask." to
> "virtio: Make vp_set_vq_affinity() take a mask."
> 
> Tested:
> 
> # 16 vCPU, 16 queue pairs, Debian 9 recent net-next kernel, GCE
> 
> # Disable GCE scripts setting affinities during startup.
> #
> # Add the following to
> # /etc/default/instance_configs.cfg.template and reboot:
> [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
> 
> # 16 vCPU, 15 queue pairs
> $ 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
> 
> # 16 vCPU, 8 queue pairs
> $ 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
> 
> # 15 vCPU, 16 queue pairs
> $ 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
> 
> # 8 vCPU, 16 queue pairs
> $ 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
> 
> Caleb Raitto (2):
>   virtio: Make vp_set_vq_affinity() take a mask.
>   virtio_net: Stripe queue affinities across cores.
> 
>  drivers/crypto/virtio/virtio_crypto_core.c |  4 +-
>  drivers/net/virtio_net.c                   | 46 ++++++++++++++--------
>  drivers/virtio/virtio_pci_common.c         |  7 ++--
>  drivers/virtio/virtio_pci_common.h         |  2 +-
>  include/linux/virtio_config.h              |  7 ++--
>  5 files changed, 39 insertions(+), 27 deletions(-)
> 
> -- 
> 2.18.0.597.ga71716f1ad-goog