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virtio_net: Stripe queue affinities across cores.

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Always set the affinity hint, even if #cpu != #vq.

Handle the case where #cpu > #vq (including when #cpu % #vq != 0) and
when #vq > #cpu (including when #vq % #cpu != 0).

Signed-off-by: Caleb Raitto <caraitto@google.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Acked-by: Jon Olson <jonolson@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Caleb Raitto 2018-08-09 17:28:40 -07:00 committed by David S. Miller
parent 19e226e8cc
commit 2ca653d607
1 changed files with 27 additions and 15 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

42
drivers/net/virtio_net.c
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@ -31,6 +31,7 @@
#include <linux/average.h> #include <linux/average.h>
#include <linux/filter.h> #include <linux/filter.h>
#include <linux/netdevice.h> #include <linux/netdevice.h>
#include <linux/kernel.h>
#include <linux/pci.h> #include <linux/pci.h>
#include <net/route.h> #include <net/route.h>
#include <net/xdp.h> #include <net/xdp.h>
@ -1888,30 +1889,41 @@ static void virtnet_clean_affinity(struct virtnet_info *vi, long hcpu)
static void virtnet_set_affinity(struct virtnet_info *vi) static void virtnet_set_affinity(struct virtnet_info *vi)
{ {
int i; cpumask_var_t mask;
int cpu; int stragglers;
int group_size;
int i, j, cpu;
int num_cpu;
int stride;
/* In multiqueue mode, when the number of cpu is equal to the number of if (!zalloc_cpumask_var(&mask, GFP_KERNEL)) {
* queue pairs, we let the queue pairs to be private to one cpu by
* setting the affinity hint to eliminate the contention.
*/
if (vi->curr_queue_pairs == 1 ||
vi->max_queue_pairs != num_online_cpus()) {
virtnet_clean_affinity(vi, -1); virtnet_clean_affinity(vi, -1);
return; return;
} }
i = 0; num_cpu = num_online_cpus();
for_each_online_cpu(cpu) { stride = max_t(int, num_cpu / vi->curr_queue_pairs, 1);
const unsigned long *mask = cpumask_bits(cpumask_of(cpu)); stragglers = num_cpu >= vi->curr_queue_pairs ?
num_cpu % vi->curr_queue_pairs :
0;
cpu = cpumask_next(-1, cpu_online_mask);
virtqueue_set_affinity(vi->rq[i].vq, cpumask_of(cpu)); for (i = 0; i < vi->curr_queue_pairs; i++) {
virtqueue_set_affinity(vi->sq[i].vq, cpumask_of(cpu)); group_size = stride + (i < stragglers ? 1 : 0);
__netif_set_xps_queue(vi->dev, mask, i, false);
i++; for (j = 0; j < group_size; j++) {
cpumask_set_cpu(cpu, mask);
cpu = cpumask_next_wrap(cpu, cpu_online_mask,
nr_cpu_ids, false);
}
virtqueue_set_affinity(vi->rq[i].vq, mask);
virtqueue_set_affinity(vi->sq[i].vq, mask);
__netif_set_xps_queue(vi->dev, cpumask_bits(mask), i, false);
cpumask_clear(mask);
} }
vi->affinity_hint_set = true; vi->affinity_hint_set = true;
free_cpumask_var(mask);
} }
static int virtnet_cpu_online(unsigned int cpu, struct hlist_node *node) static int virtnet_cpu_online(unsigned int cpu, struct hlist_node *node)