RE: Netvsc vs Failsafe Performance

[Long Li <longli@microsoft.com>]

[-- Attachment #1: Type: text/plain, Size: 5876 bytes --]

Thank you!

Are you seeing problems with UDP traffic on the receive side? If everything works fine for you, I’m sending a patch.

Long

From: Nandini Rangaswamy <nandini.rangaswamy@broadcom.com>
Sent: Monday, September 16, 2024 3:58 PM
To: Long Li <longli@microsoft.com>
Cc: Stephen Hemminger <stephen@networkplumber.org>; users@dpdk.org
Subject: Re: Netvsc vs Failsafe Performance

Hi Long,
I tested this patch and it works as expected. The UDP IPv6 RSS offload bit is set and my dpdk app is able to successfully configure the netvsc port.
Regards,
Nandini

On Fri, Sep 13, 2024 at 2:29 PM Nandini Rangaswamy <nandini.rangaswamy@broadcom.com<mailto:nandini.rangaswamy@broadcom.com>> wrote:
Thanks Long Li.
I shall try this patch and get back to you.

On Fri, Sep 13, 2024 at 2:27 PM Long Li <longli@microsoft.com<mailto:longli@microsoft.com>> wrote:
It’s a bug in netvsc for not reporting RTE_ETH_RSS_NONFRAG_IPV6_UDP. It is implied as in the case in IPV4.

Can you try the following patch?

diff --git a/drivers/net/netvsc/hn_rndis.c b/drivers/net/netvsc/hn_rndis.c
index 1ba75ee804..fe1f04d8d9 100644
--- a/drivers/net/netvsc/hn_rndis.c
+++ b/drivers/net/netvsc/hn_rndis.c
@@ -717,6 +717,7 @@ hn_rndis_query_rsscaps(struct hn_data *hv,
        if (caps.ndis_caps & NDIS_RSS_CAP_IPV6)
                hv->rss_offloads |= RTE_ETH_RSS_IPV6
                        | RTE_ETH_RSS_NONFRAG_IPV6_TCP;
+                       | RTE_ETH_RSS_NONFRAG_IPV6_UDP;
        if (caps.ndis_caps & NDIS_RSS_CAP_IPV6_EX)
                hv->rss_offloads |= RTE_ETH_RSS_IPV6_EX
                        | RTE_ETH_RSS_IPV6_TCP_EX;


From: Nandini Rangaswamy <nandini.rangaswamy@broadcom.com<mailto:nandini.rangaswamy@broadcom.com>>
Sent: Friday, September 13, 2024 10:56 AM
To: Stephen Hemminger <stephen@networkplumber.org<mailto:stephen@networkplumber.org>>
Cc: Long Li <longli@microsoft.com<mailto:longli@microsoft.com>>; users@dpdk.org<mailto:users@dpdk.org>
Subject: Re: Netvsc vs Failsafe Performance

Thanks for clarifying the question regarding Txd size Stephen.
I tested out the RSS for TCP UDP.
As suggested , I set the TCP flags alone in RSS conf and configured the netvsc port.

struct rte_eth_conf conf = {
.intr_conf = {
.lsc = !dpdk.lsc_intr_disable && !dpdk_if->lsc_intr_disable &&
!!(dev->data->dev_flags & RTE_ETH_DEV_INTR_LSC),
},
.rxmode = {
.mq_mode = RTE_ETH_MQ_RX_RSS,
.offloads = RTE_ETH_RX_OFFLOAD_VLAN_STRIP | RTE_ETH_RX_OFFLOAD_IPV4_CKSUM |
RTE_ETH_RX_OFFLOAD_RSS_HASH | RTE_ETH_RX_OFFLOAD_UDP_CKSUM,
},
.rx_adv_conf.rss_conf = {
.rss_hf = RTE_ETH_RSS_NONFRAG_IPV4_TCP | RTE_ETH_RSS_NONFRAG_IPV6_TCP,
.rss_key = conf_rss_key,
.rss_key_len = rss_key_len,
},
.txmode = {
.offloads = RTE_ETH_TX_OFFLOAD_UDP_CKSUM | RTE_ETH_TX_OFFLOAD_IPV4_CKSUM,
},
};
rte_eth_dev_configure(<netvsc port>, num_rxq,num_txq, &conf);
uint8_t rss_key_temp[64];
struct rte_eth_rss_conf rss_conf = {
.rss_key = rss_key_temp,
.rss_key_len = sizeof(rss_key_temp),
};
ret = rte_eth_dev_rss_hash_conf_get(<VF port>, &rss_conf);


Now the VF port RSS offloads show only TCP flags set and not UDP. I assumed that even the UDP flags might be set. Is this expected ?

Regards,
Nandini


On Thu, Sep 12, 2024 at 4:09 PM Stephen Hemminger <stephen@networkplumber.org<mailto:stephen@networkplumber.org>> wrote:
On Thu, 12 Sep 2024 13:47:37 -0700
Nandini Rangaswamy <nandini.rangaswamy@broadcom.com<mailto:nandini.rangaswamy@broadcom.com>> wrote:

> Thanks for your response Long Li.
> I see with netvsc the maximum number of Tx descriptors is restricted to
> 4096 whereas the number of Rx descriptors is restricted to 8192.
> But, for failsafe PMD , we see that both the number of Txd and Rxd is
> restricted to 8192.
> How is netvsc PMD giving the same performance as failsafe PMD ?
>
> Regards

I think the limits there were somewhat arbitrary chose with netvsc.
Don't remember a hard reason that would block larger sizes.


Having really big rings won't help performance (i.e BufferBloat) and
could a lot of memory consumption. When all heavy data traffic goes through
the VF and that ring is different. Only DoS attacks should be impacted
by rx/tx descriptor limits in the netvsc device. The linux driver actually
has much smaller buffer.

This electronic communication and the information and any files transmitted with it, or attached to it, are confidential and are intended solely for the use of the individual or entity to whom it is addressed and may contain information that is confidential, legally privileged, protected by privacy laws, or otherwise restricted from disclosure to anyone else. If you are not the intended recipient or the person responsible for delivering the e-mail to the intended recipient, you are hereby notified that any use, copying, distributing, dissemination, forwarding, printing, or copying of this e-mail is strictly prohibited. If you received this e-mail in error, please return the e-mail to the sender, delete it from your computer, and destroy any printed copy of it.

This electronic communication and the information and any files transmitted with it, or attached to it, are confidential and are intended solely for the use of the individual or entity to whom it is addressed and may contain information that is confidential, legally privileged, protected by privacy laws, or otherwise restricted from disclosure to anyone else. If you are not the intended recipient or the person responsible for delivering the e-mail to the intended recipient, you are hereby notified that any use, copying, distributing, dissemination, forwarding, printing, or copying of this e-mail is strictly prohibited. If you received this e-mail in error, please return the e-mail to the sender, delete it from your computer, and destroy any printed copy of it.

[-- Attachment #2: Type: text/html, Size: 31444 bytes --]