[ovs-dev] [PATCH v4 1/2] Add performance measuring API

[Ben Pfaff]

On Tue, Feb 20, 2018 at 04:13:31PM -0600, Mark Michelson wrote:
> This is similar to the existing coverage and perf-counter APIs in OVS.
> However, rather than keeping counters, this is aimed at timing how long
> operations take to perform. "Operations" in this case can be anything
> from a loop iteration, to a function, to something more complex.
> 
> The library will keep track of how long it takes to perform the
> particular operations and will maintain statistics of those running
> times.
> 
> Statistics for a particular operation can be queried from the command
> line by using ovs-appctl -t <target> performance/show <operation name>.
> 
> The API is designed to be pretty small. The expected steps are as
> follows:
> 
> 1) Create a performance measurement, providing a unique name, using
> performance_create()
> 2) Add calls to start_sample() and end_sample() to mark the start and
> stop of the operation you wish to measure.
> 
> Two CLI commands have been added:
> * Display statistics for a particular measurement.
> * Reset a particular measurement.
> 
> Signed-off-by: Mark Michelson <mmichels at redhat.com>

"sparse" pointed out that unit_name[] should be static:

../lib/performance.c:85:12: error: symbol 'unit_name' was not declared. Should it be static?