On 29/08/2022 14:44, Morten Brørup wrote:
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.
Ok, will make this change for the v4. Thanks!
