test/distributor: fix shutdown of busy worker

The sanity test with worker shutdown delegates all bufs
to be processed by a single lcore worker, then it freezes
one of the lcore workers and continues to send more bufs.
The freezed core shuts down first by calling
rte_distributor_return_pkt().

The test intention is to verify if packets assigned to
the shut down lcore will be reassigned to another worker.

However the shutdown core was not always the one, that was
processing packets. The lcore processing mbufs might be different
every time test is launched. This is caused by keeping the value
of wkr static variable in rte_distributor_process() function
between running test cases.

Test freezed always lcore with 0 id. The patch stores the id
of worker that is processing the data in zero_idx global atomic
variable. This way the freezed lcore is always the proper one.

Fixes: c3eabff124e6 ("distributor: add unit tests")
Cc: stable@dpdk.org
Signed-off-by: Lukasz Wojciechowski <l.wojciechow@partner.samsung.com>
Tested-by: David Hunt <david.hunt@intel.com>

diff --git a/app/test/test_distributor.c b/app/test/test_distributor.c
index 52230d25047a67a1300f8c10d987aebd8c003e81..6cd7a2edda1d15d2a83382f5dfd8e8d5c1e6ee38 100644 (file)
--- a/app/test/test_distributor.c
+++ b/app/test/test_distributor.c
@@ -28,6 +28,7 @@ struct worker_params worker_params;
 static volatile int quit;      /**< general quit variable for all threads */
 static volatile int zero_quit; /**< var for when we just want thr0 to quit*/
 static volatile unsigned worker_idx;
+static volatile unsigned zero_idx;
 
 struct worker_stats {
        volatile unsigned handled_packets;
@@ -340,26 +341,43 @@ handle_work_for_shutdown_test(void *arg)
        unsigned int total = 0;
        unsigned int i;
        unsigned int returned = 0;
+       unsigned int zero_id = 0;
+       unsigned int zero_unset;
        const unsigned int id = __atomic_fetch_add(&worker_idx, 1,
                        __ATOMIC_RELAXED);
 
        num = rte_distributor_get_pkt(d, id, buf, NULL, 0);
 
+       if (num > 0) {
+               zero_unset = RTE_MAX_LCORE;
+               __atomic_compare_exchange_n(&zero_idx, &zero_unset, id,
+                       false, __ATOMIC_ACQ_REL, __ATOMIC_ACQUIRE);
+       }
+       zero_id = __atomic_load_n(&zero_idx, __ATOMIC_ACQUIRE);
+
        /* wait for quit single globally, or for worker zero, wait
         * for zero_quit */
-       while (!quit && !(id == 0 && zero_quit)) {
+       while (!quit && !(id == zero_id && zero_quit)) {
                worker_stats[id].handled_packets += num;
                count += num;
                for (i = 0; i < num; i++)
                        rte_pktmbuf_free(buf[i]);
                num = rte_distributor_get_pkt(d, id, buf, NULL, 0);
+
+               if (num > 0) {
+                       zero_unset = RTE_MAX_LCORE;
+                       __atomic_compare_exchange_n(&zero_idx, &zero_unset, id,
+                               false, __ATOMIC_ACQ_REL, __ATOMIC_ACQUIRE);
+               }
+               zero_id = __atomic_load_n(&zero_idx, __ATOMIC_ACQUIRE);
+
                total += num;
        }
        worker_stats[id].handled_packets += num;
        count += num;
        returned = rte_distributor_return_pkt(d, id, buf, num);
 
-       if (id == 0) {
+       if (id == zero_id) {
                /* for worker zero, allow it to restart to pick up last packet
                 * when all workers are shutting down.
                 */
@@ -578,6 +596,7 @@ quit_workers(struct worker_params *wp, struct rte_mempool *p)
        rte_eal_mp_wait_lcore();
        quit = 0;
        worker_idx = 0;
+       zero_idx = RTE_MAX_LCORE;
 }
 
 static int