[dpdk-stable] [PATCH v2 1/1] app/test: collect perf data after worker threads exit

[Feifei Wang <feifei.wang2@arm.com>]

The measure_perf function should be executed after worker threads exit
to collect correct perf data. Otherwise, while workers are running, the
main thread may get incomplete data from workers.

In the meanwhile, remove unnecessary barrier in the test.
For signal variables "ldata.done" and "ldata.start", no operations
should keep the order that being executed after them. So the wmb after
them can be moved.

Fixes: 16a277a24c9f ("test/trace: add performance test cases")
Cc: jerinj@marvell.com
Cc: stable@dpdk.org

Suggested-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
Signed-off-by: Feifei Wang <feifei.wang2@arm.com>
Reviewed-by: Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>
Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
---
 app/test/test_trace_perf.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/app/test/test_trace_perf.c b/app/test/test_trace_perf.c
index e1ad8e6f5..46ae7d807 100644
--- a/app/test/test_trace_perf.c
+++ b/app/test/test_trace_perf.c
@@ -79,7 +79,6 @@ signal_workers_to_finish(struct test_data *data)
 
 	for (workers = 0; workers < data->nb_workers; workers++) {
 		data->ldata[workers].done = 1;
-		rte_smp_wmb();
 	}
 }
 
@@ -102,7 +101,6 @@ worker_fn_##func(void *arg) \
 { \
 	struct lcore_data *ldata = arg; \
 	ldata->started = 1; \
-	rte_smp_wmb(); \
 	__worker_##func(ldata); \
 	return 0; \
 }
@@ -137,11 +135,12 @@ run_test(const char *str, lcore_function_t f, struct test_data *data, size_t sz)
 
 	wait_till_workers_are_ready(data);
 	rte_delay_ms(100); /* Wait for some time to accumulate the stats */
-	measure_perf(str, data);
 	signal_workers_to_finish(data);
 
 	RTE_LCORE_FOREACH_WORKER(id)
 		rte_eal_wait_lcore(id);
+
+	measure_perf(str, data);
 }
 
 static int
-- 
2.25.1