> -----Original Message----- > From: Eelco Chaudron <[email protected]> > Sent: Wednesday, July 7, 2021 9:59 AM > To: Van Haaren, Harry <[email protected]> > Cc: Amber, Kumar <[email protected]>; [email protected]; > [email protected]; Flavio Leitner <[email protected]>; Stokes, Ian > <[email protected]> > Subject: Re: [ovs-dev] [v4 02/12] dpif-netdev: Add auto validation function > for > miniflow extract > > > > On 6 Jul 2021, at 15:58, Van Haaren, Harry wrote: > > >> -----Original Message----- > >> From: Eelco Chaudron <[email protected]> > >> Sent: Friday, July 2, 2021 8:10 AM > >> To: Van Haaren, Harry <[email protected]> > >> Cc: Amber, Kumar <[email protected]>; [email protected]; > >> [email protected]; Flavio Leitner <[email protected]>; Stokes, Ian > >> <[email protected]> > >> Subject: Re: [ovs-dev] [v4 02/12] dpif-netdev: Add auto validation > >> function for > >> miniflow extract > >> > >> > >> > >> On 1 Jul 2021, at 19:24, Van Haaren, Harry wrote: > >> > >>>> -----Original Message----- > >>>> From: Eelco Chaudron <[email protected]> > > > > <snip ascii table/data and previous conversations> > > > >>>> I’ll share the google sheet with you directly as it also has the config, > >>>> and PVP > >> results. > >>> > >>> I can't actually access that doc, sorry. Results above are enough to go > >>> by for > now :) > >> > >> It’s attached. > > > > Thanks. > > > >>> We can investigate if there's any optimizations to be done to improve the > scalar DPIF > >>> enabling of the miniflow extract func ptr, but I'm not sure there is. > > > > Note the v6 of MFEX has some minor changes/optimizations in place, as per > scalar DPIF enabling in this patch: > > > https://patchwork.ozlabs.org/project/openvswitch/patch/20210706131150.45513 > [email protected]/ > > > > > >>> If we cannot improve the perf data from above, there is an option to not > enable > >> the scalar DPIF with the AVX512 MFEX optimizations. (Logic being if AVX512 > >> is > present, > >> running both the DPIF + MFEX makes sense). What do you think? > > > > If you feel it is required before merge, would you re-run the benchmark on > > v6? > > If so, we're targeting Thursday for merge, so data ASAP, or by EOD tomorrow > would be required. > > I’m reviewing your v6 now, so I have no cycles to also do the testing before > the > end of the week. But the tests are simple, so maybe you guys can try it and > report the difference with and without the two patchsets applied on a non > AVX512 machine?
Yes, we have done scalar-only code benchmarking of master vs with DPIF patchset. By not enabling AVX512 at runtime we get the "non AVX512 machine" behaviour. (All the scalar code is common, no need to a specific CPU in that instance). Testing OVS master branch vs with patchset did not show up any performance delta on the test machines here, so there's nothing I can do. By removing scalar DPIF enabling of MFEX opt pointer (details below) we remove any urgency on benchmark results? > > As mentioned above, there is an option to remove the AVX512-Optimized > MFEX enabling > > from the scalar datapath, if there is measurable/significant performance > reduction in this v6 code. > > It not clear to me what you mean by this? Can you elaborate? I’m running this > on > a non AVX512 machine, all with default configs. I'm suggesting that if you're not OK with merging the ~1.x% negative performance on scalar DPIF performance to enable MFEX, we can remove the MFEX enabling from the scalar DPIF. Logically, if AVX512 is in use for MFEX, it is logical to use the AVX512 DPIF too, hence this is a workable solution/workaround for scalar DPIF performance loss. Taking this approach would ensure that scalar DPIF performance is not reduced in this release, and we can re-visit scalar DPIF enabling of MFEX in future if desired? Overall, this seems the pragmatic way of reducing risk around performance and getting merged. > >> This is on a system without AVX512 support, so all is disabled. The > >> “without > patch” > >> has both the new AVX patches removed (mfex and dpif framework). > >> > >>> > >>>> //Eelco > > > > Thanks again for testing & follow up! Regards, -Harry _______________________________________________ dev mailing list [email protected] https://mail.openvswitch.org/mailman/listinfo/ovs-dev
