Re: [dpdk-dev] [PATCH] test/service: add perf test for service on app lcore

[David Marchand <david.marchand@redhat.com>]

On Fri, May 1, 2020 at 5:56 PM Harry van Haaren
<harry.van.haaren@intel.com> wrote:
>
> Add a performance test to the service run on app lcore auto-
> test. This test runs the service in a tight loop, and measures
> cycles passed, printing the results. It provides a quick cycle
> cost value, enabling measuring performance of the function to
> run a service on an application lcore.
>
> Signed-off-by: Harry van Haaren <harry.van.haaren@intel.com>
>
> ---
>
> I'm suggesting to merge this patch before the bugfix/C11 patch series,
> (v2 currently here: http://patches.dpdk.org/patch/69199/ )
> as this would enable users to benchmark the "before" and "after"
> states of the bugfix/C11 patches easier.
>
> ---
>  app/test/test_service_cores.c | 12 +++++++++++-
>  1 file changed, 11 insertions(+), 1 deletion(-)
>
> diff --git a/app/test/test_service_cores.c b/app/test/test_service_cores.c
> index a922c7ddc..469243314 100644
> --- a/app/test/test_service_cores.c
> +++ b/app/test/test_service_cores.c
> @@ -789,8 +789,18 @@ service_app_lcore_poll_impl(const int mt_safe)
>                                 "MT Unsafe: App core1 didn't return -EBUSY");
>         }
>
> -       unregister_all();
> +       /* Performance test: call in a loop, and measure tsc() */
> +       const uint32_t perf_iters = (1 << 12);
> +       uint64_t start = rte_rdtsc();
> +       for (uint32_t i = 0; i < perf_iters; i++) {

- How long does this test take now?
We tend to put performance tests in dedicated tests to avoid issues in Travis.
I suppose this is quick, but still want a confirmation.


- Centos7/RHEL7 gcc is not happy with this.

http://mails.dpdk.org/archives/test-report/2020-May/129993.html

../app/test/test_service_cores.c: In function ‘service_app_lcore_poll_impl’:
../app/test/test_service_cores.c:795:2: error: ‘for’ loop initial
declarations are only allowed in C99 mode
  for (uint32_t i = 0; i < perf_iters; i++) {
  ^
../app/test/test_service_cores.c:795:2: note: use option -std=c99 or
-std=gnu99 to compile your code


> +               int err = service_run_on_app_core_func(&id);
> +               TEST_ASSERT_EQUAL(0, err, "perf test: returned run failure");
> +       }
> +       uint64_t end = rte_rdtsc();
> +       printf("perf test for %s: %0.1f cycles per call\n", mt_safe ?
> +               "MT Safe" : "MT Unsafe", (end - start)/(float)perf_iters);
>
> +       unregister_all();
>         return TEST_SUCCESS;
>  }
>

- Can you look at Phil comments too?


-- 
David Marchand