[Bug 1147] ENA NET PMD tracing function enabled on transmit fastpath in non-debug builds

[bugzilla at dpdk.org]

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: dev at dpdk.org
          Reporter: declan.doherty at intel.com
  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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