From 646f071d315b75e87583de290d333478d42ccde1 Mon Sep 17 00:00:00 2001 From: Erni Sri Satya Vennela Date: Mon, 26 Aug 2024 22:16:31 -0700 Subject: [PATCH] net: netvsc: Update default VMBus channels Change VMBus channels macro (VRSS_CHANNEL_DEFAULT) in Linux netvsc from 8 to 16 to align with Azure Windows VM and improve networking throughput. For VMs having less than 16 vCPUS, the channels depend on number of vCPUs. For greater than 16 vCPUs, set the channels to maximum of VRSS_CHANNEL_DEFAULT and number of physical cores / 2 which is returned by netif_get_num_default_rss_queues() as a way to optimize CPU resource utilization and scale for high-end processors with many cores. Maximum number of channels are by default set to 64. Based on this change the channel creation would change as follows: ----------------------------------------------------------------- | No. of vCPU | dev_info->num_chn | channels created | ----------------------------------------------------------------- | 1-16 | 16 | vCPU | | >16 | max(16,#cores/2) | min(64 , max(16,#cores/2)) | ----------------------------------------------------------------- Performance tests showed significant improvement in throughput: - 0.54% for 16 vCPUs - 0.83% for 32 vCPUs - 0.86% for 48 vCPUs - 9.72% for 64 vCPUs - 13.57% for 96 vCPUs Signed-off-by: Erni Sri Satya Vennela Reviewed-by: Haiyang Zhang Reviewed-by: Shradha Gupta Reviewed-by: Michael Kelley Link: https://patch.msgid.link/1724735791-22815-1-git-send-email-ernis@linux.microsoft.com Signed-off-by: Jakub Kicinski --- drivers/net/hyperv/hyperv_net.h | 2 +- drivers/net/hyperv/netvsc_drv.c | 3 ++- 2 files changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/net/hyperv/hyperv_net.h b/drivers/net/hyperv/hyperv_net.h index 810977952f95..e690b95b1bbb 100644 --- a/drivers/net/hyperv/hyperv_net.h +++ b/drivers/net/hyperv/hyperv_net.h @@ -882,7 +882,7 @@ struct nvsp_message { #define VRSS_SEND_TAB_SIZE 16 /* must be power of 2 */ #define VRSS_CHANNEL_MAX 64 -#define VRSS_CHANNEL_DEFAULT 8 +#define VRSS_CHANNEL_DEFAULT 16 #define RNDIS_MAX_PKT_DEFAULT 8 #define RNDIS_PKT_ALIGN_DEFAULT 8 diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c index 44142245343d..153b97f8ec0d 100644 --- a/drivers/net/hyperv/netvsc_drv.c +++ b/drivers/net/hyperv/netvsc_drv.c @@ -987,7 +987,8 @@ struct netvsc_device_info *netvsc_devinfo_get(struct netvsc_device *nvdev) dev_info->bprog = prog; } } else { - dev_info->num_chn = VRSS_CHANNEL_DEFAULT; + dev_info->num_chn = max(VRSS_CHANNEL_DEFAULT, + netif_get_num_default_rss_queues()); dev_info->send_sections = NETVSC_DEFAULT_TX; dev_info->send_section_size = NETVSC_SEND_SECTION_SIZE; dev_info->recv_sections = NETVSC_DEFAULT_RX;