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net: netvsc: Update default VMBus channels

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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 <ernis@linux.microsoft.com>
Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>
Reviewed-by: Shradha Gupta <shradhagupta@linux.microsoft.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Link: https://patch.msgid.link/1724735791-22815-1-git-send-email-ernis@linux.microsoft.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Erni Sri Satya Vennela 2024-08-26 22:16:31 -07:00 committed by Jakub Kicinski
parent e24a6c8746
commit 646f071d31
2 changed files with 3 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
drivers/net/hyperv/hyperv_net.h
View File

@ -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

3
drivers/net/hyperv/netvsc_drv.c
View File

@ -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;