On 15-Jul-22 2:12 PM, Anatoly Burakov wrote:
Currently, there is no way to measure lcore 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 busyness.
The busyness is calculated by relying on the fact that most DPDK API's
will poll for packets. Empty polls can be counted as "idle", while
non-empty polls can be counted as busy. To measure lcore 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 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 telemetry calls:
- All major driver API's:
- ethdev
- cryptodev
- compressdev
- regexdev
- bbdev
- rawdev
- eventdev
- 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
also possible to disable it at compile time by commenting out
RTE_LCORE_BUSYNESS from build config.
This patch also adds a telemetry endpoint to report lcore busyness, as
well as telemetry endpoints to enable/disable lcore telemetry.
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>
---
These patches are to be applied on top of 20.11, so please ignore this
patchset. I've already marked it as "Not Applicable" in patchwork.
--
Thanks,
Anatoly
