benchmarking Podman: proof of concept

Add a proof of concept for benchmarking Podman.  The benchmarks are
implemented by means of the end-to-end test suite but hidden behind
a `benchmarks` build tag.  Running `make localbenchmarks` will run
`test/e2e` with the specific build tag and set ginkgo's "focus" to
the specific "Podman Benchmark Suite" to only run this spec and skip
all others.

ginkgo will print a report before terminating listing the CPU and memory
stats for each benchmark.  New benchmarks can easily be added via the
`newBenchmark` function that also supports adding an `init()` function
to each benchmark which allows for performing certain setups for the
specific benchmark.  For instance, benchmarking `podman start` requires
creating a container beforehand.

Podman may be called more than once in the main function of a benchmark
but note that the displayed memory consumption is then a sum of all
Podman invocations.  The memory consumption is collected via
`/usr/bin/time`.

A benchmark's report is split into CPU and memory as displayed below:

```
[CPU] podman images:
  Fastest Time: 0.146s
  Slowest Time: 0.187s
  Average Time: 0.180s ± 0.015s
[MEM] podman images:
  Smallest: 41892.0KB
   Largest: 42792.0KB
   Average: 42380.7KB ± 286.4KB
```

Note that the benchmarks are not wired into the CI yet.  They are meant
as a proof of concept.  More benchmarks and the plumbing into CI will
happen in a later change.

Signed-off-by: Valentin Rothberg <vrothberg@redhat.com>

0 files changed, 0 insertions, 0 deletions