> -----Original Message----- > From: Flavio Leitner [mailto:f...@sysclose.org] > Sent: Tuesday, June 16, 2015 6:28 PM > To: Daniele Di Proietto > Cc: Traynor, Kevin; dev@openvswitch.org; Gray, Mark D > Subject: Re: [ovs-dev] Is this an issue for DPDK vhost rss? > > On Mon, Jun 15, 2015 at 05:55:13PM +0000, Daniele Di Proietto wrote: > > On 15/06/2015 12:16, "Traynor, Kevin" <kevin.tray...@intel.com> wrote: > > >There is a dpdk patchset that contains a potential fix for this and lots > > >of > > >other changes, but I haven't tested yet. > > >https://urldefense.proofpoint.com/v2/url?u=http-3A__dpdk.org_ml_archives_d > > >ev_2015-2DJune_018436.html&d=BQIFAg&c=Sqcl0Ez6M0X8aeM67LKIiDJAXVeAw-YihVMN > > >tXt-uEs&r=SmB5nZacmXNq0gKCC1s_Cw5yUNjxgD4v5kJqZ2uWLlE&m=FDVPKa2SqwpyYOTmA2 > > >zGdscCPa1FVdQG3Zbr4tHrp38&s=fjg7wArWvYLJlgEGKijK6W6ECAxGk660UrPF3rAr4Rs&e= > > I skimmed over the patchset and it is an ABI breaker, so I > think the policy demands to announce it on 2.1 and merge only > in 2.2 release.
I tested with a subset of the patches and the ol_flags.rss bit is being set correctly. It could be merged and available in DPDK 2.1 with a config parameter. However, even with this we'd need to assess the rest of the changes and compatibility with OVS. > > Maybe it is possible to separate the ol_flags fix into a > smaller and simple patch to be accepted as bugfix yet in 2.1. That would be ideal. > > > > >> > Otherwise, should we avoid using the vectorized version? > > >> > > >> that's debatable - from a performance view it may be better to leave it > > >>in > > >> and take the hit elsewhere for the time being if there's a possibility > > >>that > > >> it will be changed in DPDK later. > > > > > >With a loop to reset the rss after the rte_vhost_dequeue_burst() call I'm > > >seeing a drop of ~100kpps in vhost performance. Rx vectoristion gives a > > >gain > > >of about ~1 mpps on my system for the phy2phy cases. > > > > > >Using the ol_flags check is the right option when DPDK supports setting it > > >correctly with rx vectorisation. In the meantime there's choice of using > > >the > > >reset loop or removing rx vectorisation - what do you think? > > > > Thanks for sharing these results. I've observed that if OVS can't use the > > RSS > > hash and has to compute we lose ~2Mpps on a single flow phy2phy test. > > > > Despite this, I still think we should consider the ol_flags because: > > > > * DPDK drivers (other than ixgbe) should use ol_flags as well to mark the > > RSS hash as valid > > * ixgbe_recv_pkts_vec() will report PKT_RX_RSS_HASH in future releases (the > > patch you sent will be effective since DPDK 2.2, right?) > > I agree with the above. > > > If the throughput with the non-vector rx routine is higher we can disable > > the vector rx as a temporary workaround. > > Could you point me to the vector and non-vector rx routines? > I feel like I am missing something. > > Thanks, > fbl _______________________________________________ dev mailing list dev@openvswitch.org http://openvswitch.org/mailman/listinfo/dev
