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@dpdk.org
Reporter: declan.dohe...@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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