Bug 1147
| Summary: | ENA NET PMD tracing function enabled on transmit fastpath in non-debug builds | ||
|---|---|---|---|
| Product: | DPDK | Reporter: | Declan Doherty (declan.doherty) |
| Component: | ethdev | Assignee: | dev |
| Status: | UNCONFIRMED --- | ||
| Severity: | major | CC: | shaibran |
| Priority: | Normal | ||
| Version: | 21.08 | ||
| Target Milestone: | --- | ||
| Hardware: | All | ||
| OS: | Linux | ||
| Attachments: | Flamegraph of testpmd and ena pmd on AWS | ||
I will review the ena macro to check if there is a need to separate the macro for fastpath to avoid the time consuming check |
Created attachment 237 [details] 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.