On Fri, Sep 2, 2022 at 9:26 PM Kevin Laatz <kevin.la...@intel.com> wrote: > > From: Anatoly Burakov <anatoly.bura...@intel.com> > > Currently, there is no way to measure lcore poll busyness in a passive way, > without any modifications to the application. This patch adds a new EAL API > that will be able to passively track core polling busyness. > > The poll busyness is calculated by relying on the fact that most DPDK API's > will poll for work (packets, completions, eventdev events, etc). Empty > polls can be counted as "idle", while non-empty polls can be counted as > busy. To measure lcore poll busyness, we simply call the telemetry > timestamping function with the number of polls a particular code section > has processed, and count the number of cycles we've spent processing empty > bursts. The more empty bursts we encounter, the less cycles we spend in > "busy" state, and the less core poll busyness will be reported. > > In order for all of the above to work without modifications to the > application, the library code needs to be instrumented with calls to the > lcore telemetry busyness timestamping function. The following parts of DPDK > are instrumented with lcore poll busyness timestamping calls: > > - All major driver API's: > - ethdev > - cryptodev > - compressdev > - regexdev > - bbdev > - rawdev > - eventdev > - dmadev > - Some additional libraries: > - ring > - distributor > > To avoid performance impact from having lcore telemetry support, a global > variable is exported by EAL, and a call to timestamping function is wrapped > into a macro, so that whenever telemetry is disabled, it only takes one > additional branch and no function calls are performed. It is disabled at > compile time by default. > > This patch also adds a telemetry endpoint to report lcore poll busyness, as > well as telemetry endpoints to enable/disable lcore telemetry. A > documentation entry has been added to the howto guides to explain the usage > of the new telemetry endpoints and API. > > Signed-off-by: Kevin Laatz <kevin.la...@intel.com> > Signed-off-by: Conor Walsh <conor.wa...@intel.com> > Signed-off-by: David Hunt <david.h...@intel.com> > Signed-off-by: Anatoly Burakov <anatoly.bura...@intel.com>
This version looks good to me. Thanks for this new feature. I think, we need to add a UT for this new rte_lcore_poll_* APIs also add a performance test case to measure the cycles for RTE_LCORE_POLL_BUSYNESS_TIMESTAMP [1] [1] Reference performance test application for trace: app/test/test_trace_perf.c
