> From: Kevin Laatz [mailto:kevin.la...@intel.com] > Sent: Monday, 29 August 2022 15.37 > > On 29/08/2022 13:49, Morten Brørup wrote: > > From: Kevin Laatz [mailto:kevin.la...@intel.com] > > Sent: Monday, 29 August 2022 14.37 > >> The patches currently include runtime options to enable/disable the > feature via API and via telemetry endpoints. We have run performance > tests and have failed to measure any performance impact with the > feature runtime disabled. > > Lots of features are added to DPDK all the time, and they all use the > same "insignificant performance impact" argument. But the fact is, each > added test-and-branch has some small performance impact (and consume > some entries in the branch prediction table, which may impact > performance elsewhere). If you add a million features using this > argument, there will be a significant and measurable performance > impact. > > > > Which is why I keep insisting on the ability to omit non-core > features from DPDK at build time. > > I think there's general consensus in having a buildtime option to > disable it. > > Do we agree that it should be buildtime enabled, and runtime disabled > by > default (so just the single additional branch by default), with the > meson option available to disable it completely at buildtime?
No. This feature is in the fast path, so please follow the "enable_trace_fp" design pattern, which also has fast path trace disabled at build time. -Morten
