On 8/15/2024 8:32 PM, Adel Belkhiri wrote: > Hi DPDK Community, > > I am currently working on developing performance analyses for > applications using the ethdev library. These analyses are being > implemented in Trace Compass, an open-source performance analyzer. One > of the views I’ve implemented shows the rate of traffic received or sent > by an ethernet port, measured in packets per second. However, I've > encountered an issue with the lib.ethdev.rx.burst event, which triggers > even when no packets are polled, leading to a significant number of > irrelevant events in the trace. This becomes problematic as these > "empty" events can overwhelm the tracer buffer, potentially causing the > loss of more critical events due to their high frequency. > > To address this, I've modified the DPDK code in lib/ethdev/rte_ethdev.h > to add a conditional statement that only triggers the event when nb_rx > > 0. My question to the community is whether there are use cases where an > "empty" lib.ethdev.rx.burst event could be useful. If not, would there > be interest in submitting a patch with this modification? >
Tracepoint is good way to get frequency of the calls, so I believe there can be value of getting empty burst calls too. But your usecase also a valid one. I wonder if it works to have separate trace calls, for empty and non-empty ones, and how this additional branching impacts the performance, at least branch should be wrapped with 'RTE_ENABLE_TRACE_FP' macro to not impact non-tracing usage.
