From e01ec2199ef22e2cabd7d6e68a192f3eb728029f Mon Sep 17 00:00:00 2001 From: KY Srinivasan Date: Wed, 27 May 2015 13:16:57 -0700 Subject: [PATCH] hv_netvsc: Properly size the vrss queues The current algorithm for deciding on the number of VRSS channels is not optimal since we open up the min of number of CPUs online and the number of VRSS channels the host is offering. So on a 32 VCPU guest we could potentially open 32 VRSS subchannels. Experimentation has shown that it is best to limit the number of VRSS channels to the number of CPUs within a NUMA node. Here is the new algorithm for deciding on the number of sub-channels we would open up: 1) Pick the minimum of what the host is offering and what the driver in the guest is specifying as the default value. 2) Pick the minimum of (1) and the numbers of CPUs in the NUMA node the primary channel is bound to. Signed-off-by: K. Y. Srinivasan Signed-off-by: David S. Miller --- drivers/net/hyperv/hyperv_net.h | 1 + drivers/net/hyperv/netvsc_drv.c | 4 ++++ drivers/net/hyperv/rndis_filter.c | 16 ++++++++++++++-- 3 files changed, 19 insertions(+), 2 deletions(-) diff --git a/drivers/net/hyperv/hyperv_net.h b/drivers/net/hyperv/hyperv_net.h index ddcc7f8d22b4..dd4544085db3 100644 --- a/drivers/net/hyperv/hyperv_net.h +++ b/drivers/net/hyperv/hyperv_net.h @@ -161,6 +161,7 @@ struct netvsc_device_info { unsigned char mac_adr[ETH_ALEN]; bool link_state; /* 0 - link up, 1 - link down */ int ring_size; + u32 max_num_vrss_chns; }; enum rndis_device_state { diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c index d9c88bc09f45..358475ed9b59 100644 --- a/drivers/net/hyperv/netvsc_drv.c +++ b/drivers/net/hyperv/netvsc_drv.c @@ -46,6 +46,8 @@ static int ring_size = 128; module_param(ring_size, int, S_IRUGO); MODULE_PARM_DESC(ring_size, "Ring buffer size (# of pages)"); +static int max_num_vrss_chns = 8; + static const u32 default_msg = NETIF_MSG_DRV | NETIF_MSG_PROBE | NETIF_MSG_LINK | NETIF_MSG_IFUP | NETIF_MSG_IFDOWN | NETIF_MSG_RX_ERR | @@ -755,6 +757,7 @@ static int netvsc_change_mtu(struct net_device *ndev, int mtu) ndevctx->device_ctx = hdev; hv_set_drvdata(hdev, ndev); device_info.ring_size = ring_size; + device_info.max_num_vrss_chns = max_num_vrss_chns; rndis_filter_device_add(hdev, &device_info); netif_tx_wake_all_queues(ndev); @@ -975,6 +978,7 @@ static int netvsc_probe(struct hv_device *dev, /* Notify the netvsc driver of the new device */ device_info.ring_size = ring_size; + device_info.max_num_vrss_chns = max_num_vrss_chns; ret = rndis_filter_device_add(dev, &device_info); if (ret != 0) { netdev_err(net, "unable to add netvsc device (ret %d)\n", ret); diff --git a/drivers/net/hyperv/rndis_filter.c b/drivers/net/hyperv/rndis_filter.c index 9118cea91882..006c1b8c2385 100644 --- a/drivers/net/hyperv/rndis_filter.c +++ b/drivers/net/hyperv/rndis_filter.c @@ -1013,6 +1013,9 @@ int rndis_filter_device_add(struct hv_device *dev, struct ndis_recv_scale_cap rsscap; u32 rsscap_size = sizeof(struct ndis_recv_scale_cap); u32 mtu, size; + u32 num_rss_qs; + const struct cpumask *node_cpu_mask; + u32 num_possible_rss_qs; rndis_device = get_rndis_device(); if (!rndis_device) @@ -1100,9 +1103,18 @@ int rndis_filter_device_add(struct hv_device *dev, if (ret || rsscap.num_recv_que < 2) goto out; + num_rss_qs = min(device_info->max_num_vrss_chns, rsscap.num_recv_que); + net_device->max_chn = rsscap.num_recv_que; - net_device->num_chn = (num_online_cpus() < rsscap.num_recv_que) ? - num_online_cpus() : rsscap.num_recv_que; + + /* + * We will limit the VRSS channels to the number CPUs in the NUMA node + * the primary channel is currently bound to. + */ + node_cpu_mask = cpumask_of_node(cpu_to_node(dev->channel->target_cpu)); + num_possible_rss_qs = cpumask_weight(node_cpu_mask); + net_device->num_chn = min(num_possible_rss_qs, num_rss_qs); + if (net_device->num_chn == 1) goto out; -- 2.20.1