25/01/2023 10:30, Hanumanth Reddy Pothula: > ++ Ivan Malov and Andrew Rybchenko > > From: Ferruh Yigit <ferruh.yi...@amd.com> > > On 12/21/2022 2:07 AM, Hanumanth Pothula wrote: > > > Presently, Rx metadata is sent to PMD by default, leading to a > > > performance drop as processing for the same in Rx path takes extra > > > cycles. > > > > > > Hence, add new testpmd command, > > > 'enable port <port_id> nic_to_pmd_rx_metadata' > > > > > > This command helps in sending Rx metadata to PMD and thereby Rx > > > metadata flow command requests are processed. > > > > > > Signed-off-by: Hanumanth Pothula <hpoth...@marvell.com> > > > > Hi Hanumanth, > > > > I agree with Thomas for the patch. > > > > 'eth_rx_metadata_negotiate_mp()' requests all Rx metadata offloads to be > > enabled, but at this stage if there is no flow rule for Rx metadata why it > > is > > consuming extra cycles? > > > > Can you update driver code to process Rx metadata when it is enabled by > > application (via 'rte_eth_rx_metadata_negotiate()') AND there is at least > > one flow rule for it? > > #1 What is the purpose of rte_eth_rx_metadata_negotiate() API if it is always > called by testpmd. > We thought it was added so that when that metadata is not needed, application > need not call this > thereby saving cycles/bandwidth.
testpmd is for testing all features. That's why all is negotiated. Cycles should be saved if you don't enable it until a flow rule requires it. > #2 We use this API similar to Rx/Tx offload flags so that we can set things > up before device is > configured. We thought that is the purpose of having this negotiate API and > avoid depleting offload flags. It is just a configuration negotiation specific to metadata. > #3 Generally any new offloads added to DPDK would be in disabled state in > testpmd and we would have > an option to enable it. In this case, testpmd is by default calling this > negotiation. Negotiating is not enabling. > We can update the driver if the purpose of this API is clear. Please do.
