Re: [dpdk-dev] [PATCH v2] ethdev: add IPv4 checksum RSS offload type
From: Andrew Rybchenko <hidden>
Date: 2021-06-03 08:17:20
On 6/3/21 11:03 AM, Alvin Zhang wrote:
This patch defines new RSS offload type for IPv4 checksum, which is required when users want to distribute packets based on the IPv4 checksum field. For example "flow create 0 ingress pattern eth / ipv4 / end actions rss types ipv4-chksum end queues end / end", this flow causes all matching packets to be distributed to queues on basis of IPv4 checksum. Signed-off-by: Alvin Zhang <redacted>
The patch LGTM now. I hope we'll have a PMD in the release cycle which supports it. In fact it is a funny idea. Let's consider a TCP connection and routing change with one extra hop on the way while the connection is alive. Or a UDP stream in the same conditions. If so, TTL will different, checksum changes and connection packets may be delivered to a different Rx queue. May be sometimes it is not important and/or can't happen. L4 checksum sounds better from this point of view since it covers IP addresses and transport ports and less bits to hash. The only concern is distribution fairness, but I keep the topic to those who understand corresponding math better.
quoted hunk ↗ jump to hunk
--- app/test-pmd/cmdline.c | 2 ++ app/test-pmd/config.c | 1 + lib/ethdev/rte_ethdev.h | 1 + 3 files changed, 4 insertions(+)diff --git a/app/test-pmd/cmdline.c b/app/test-pmd/cmdline.c index 0268b18..32da066 100644 --- a/app/test-pmd/cmdline.c +++ b/app/test-pmd/cmdline.c@@ -2254,6 +2254,8 @@ struct cmd_config_rss { rss_conf.rss_hf = ETH_RSS_ECPRI; else if (!strcmp(res->value, "mpls")) rss_conf.rss_hf = ETH_RSS_MPLS; + else if (!strcmp(res->value, "ipv4-chksum")) + rss_conf.rss_hf = ETH_RSS_IPV4_CHKSUM; else if (!strcmp(res->value, "none")) rss_conf.rss_hf = 0; else if (!strcmp(res->value, "level-default")) {diff --git a/app/test-pmd/config.c b/app/test-pmd/config.c index 43c79b5..2c0c415 100644 --- a/app/test-pmd/config.c +++ b/app/test-pmd/config.c@@ -140,6 +140,7 @@ { "gtpu", ETH_RSS_GTPU }, { "ecpri", ETH_RSS_ECPRI }, { "mpls", ETH_RSS_MPLS }, + { "ipv4-chksum", ETH_RSS_IPV4_CHKSUM }, { NULL, 0 }, };diff --git a/lib/ethdev/rte_ethdev.h b/lib/ethdev/rte_ethdev.h index faf3bd9..f10d834 100644 --- a/lib/ethdev/rte_ethdev.h +++ b/lib/ethdev/rte_ethdev.h@@ -537,6 +537,7 @@ struct rte_eth_rss_conf { #define ETH_RSS_PPPOE (1ULL << 31) #define ETH_RSS_ECPRI (1ULL << 32) #define ETH_RSS_MPLS (1ULL << 33) +#define ETH_RSS_IPV4_CHKSUM (1ULL << 34) /* * We use the following macros to combine with above ETH_RSS_* for