<div dir="ltr">Hi Team,<div><br></div><div><p dir="auto" style="box-sizing:border-box;margin-bottom:16px;color:rgb(31,35,40);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","Noto Sans",Helvetica,Arial,sans-serif,"Apple Color Emoji","Segoe UI Emoji";font-size:14px;margin-top:0px">We are using a C3 GCP instance having GVNIC with DPDK enabled.<br style="box-sizing:border-box">We are using latest version of DPDK ( dpdk-24.03 ) to configure RSS key, we understand C3 GCP instance with gvnic supports Toeplitz rss algorithm ( Reference - <a href="https://github.com/google/compute-virtual-ethernet-dpdk/blob/main/gve_ethdev.c" style="box-sizing:border-box;background-color:transparent">https://github.com/google/compute-virtual-ethernet-dpdk/blob/main/gve_ethdev.c</a> ), but we are hitting below issue.</p><p dir="auto" style="box-sizing:border-box;margin-top:0px;margin-bottom:16px;color:rgb(31,35,40);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","Noto Sans",Helvetica,Arial,sans-serif,"Apple Color Emoji","Segoe UI Emoji";font-size:14px"><strong style="box-sizing:border-box">Problem Statement - The RSS Hash value returned by the gvnic driver is different and is not matching the one computed by Toeplitz.</strong></p><p dir="auto" style="box-sizing:border-box;margin-top:0px;margin-bottom:16px;color:rgb(31,35,40);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","Noto Sans",Helvetica,Arial,sans-serif,"Apple Color Emoji","Segoe UI Emoji";font-size:14px">Using below script to compute rss hash value from Toeplitz.<br style="box-sizing:border-box">(<a href="https://gist.github.com/joongh/16867705b03b49e393cbf91da3cb42a7" style="box-sizing:border-box;background-color:transparent">https://gist.github.com/joongh/16867705b03b49e393cbf91da3cb42a7</a>)</p><p dir="auto" style="box-sizing:border-box;margin-top:0px;margin-bottom:16px;color:rgb(31,35,40);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","Noto Sans",Helvetica,Arial,sans-serif,"Apple Color Emoji","Segoe UI Emoji";font-size:14px">Consider below data to compute RSS Hash value -</p><p dir="auto" style="box-sizing:border-box;margin-top:0px;margin-bottom:16px;color:rgb(31,35,40);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","Noto Sans",Helvetica,Arial,sans-serif,"Apple Color Emoji","Segoe UI Emoji";font-size:14px">Source IP - 79.124.62.122<br style="box-sizing:border-box">Destination IP - 192.168.7.28<br style="box-sizing:border-box">Source Port - 49442<br style="box-sizing:border-box">Destination Port - 55327<br style="box-sizing:border-box">RSS Key - {0x94e3e97e, 0x4abac401, 0x1e0edbf, 0xe059e1f4, 0xb6e27dff, 0xdf55c916, 0xe9e6e4db, 0x1f9fb82c, 0x1e0edbf, 0xe059e1f4}</p><p dir="auto" style="box-sizing:border-box;margin-top:0px;margin-bottom:16px;color:rgb(31,35,40);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","Noto Sans",Helvetica,Arial,sans-serif,"Apple Color Emoji","Segoe UI Emoji";font-size:14px"><strong style="box-sizing:border-box">Hash Value returned by Toeplitz - 0x8bbafd0f</strong></p><p dir="auto" style="box-sizing:border-box;margin-top:0px;margin-bottom:16px;color:rgb(31,35,40);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","Noto Sans",Helvetica,Arial,sans-serif,"Apple Color Emoji","Segoe UI Emoji";font-size:14px">Gvnic dpdk pmd driver which uses Toeplitz RSS hash algorithm too is expected to compute above RSS Hash value but we see the Hash value stored in dpdk mbuf to be 0xc6a15941 which is not right.<br style="box-sizing:border-box">From the DPDK side we have ensured RSS offloading configuration is done appropriately, but still we are seeing above mismatch.</p><p dir="auto" style="box-sizing:border-box;margin-top:0px;margin-bottom:16px;color:rgb(31,35,40);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","Noto Sans",Helvetica,Arial,sans-serif,"Apple Color Emoji","Segoe UI Emoji";font-size:14px">We request you to please help us understand why this mismatch is happening and is this expected behavior of gvnic on C3 instance.</p><p style="box-sizing:border-box;margin-top:0px;margin-bottom:16px;color:rgb(31,35,40);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","Noto Sans",Helvetica,Arial,sans-serif,"Apple Color Emoji","Segoe UI Emoji";font-size:14px">Thanks,</p><p style="box-sizing:border-box;margin-top:0px;margin-bottom:16px;color:rgb(31,35,40);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","Noto Sans",Helvetica,Arial,sans-serif,"Apple Color Emoji","Segoe UI Emoji";font-size:14px">Nagesh</p></div></div>