ENA NET PMD tracing function enabled on transmit fastpath in non-debug builds

https://bugs.dpdk.org/show_bug.cgi?id=1147

Bug ID: 1147
Summary: ENA NET PMD tracing function enabled on transmit
fastpath in non-debug builds
Product: DPDK
Version: 21.08
Hardware: All
OS: Linux
Status: UNCONFIRMED
Severity: major
Priority: Normal
Component: ethdev
Assignee: [email protected]
Reporter: [email protected]
Target Milestone: ---

Created attachment 237
--> https://bugs.dpdk.org/attachment.cgi?id=237&action=edit
Flamegraph of testpmd and ena pmd on AWS

During performance benchmarking on AWS with VPP, a significant cycle count increase was noticed within the ENA PMD transmit burst.

Further investigation with testpmd shows the same cycle count increase, which is in the order of 10 X compared to pre 21.08 release.

The issues seems to relate to in changes in commit 0a001d69bca086c5a6e62b10552192380efee1f0, which changes the default behaviour of the ena_trc_** macros, some of which are on the fast path, to always invoke rte_log.

See attach flame graph, for testpmd in mac forward mode, where a huge percentage of time is spent checking whether to log the trace.

Issue seems to effect all version of DPDK from 21.08 forwards.

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