[PATCH net-next] selftests: drv-net: rss_ctx: Add retries to test_rss_context_overlap to reduce flakes

[PATCH net-next] selftests: drv-net: rss_ctx: Add retries to test_rss_context_overlap to reduce flakes

[Zinc Lim]

Similar to commit 690043b95c18 ("selftests: drv-net: rss: Add
retries to test_rss_key_indir to reduce flakes"), implement the
retry mechanism for test_rss_context_overlap. This gives the test
more attempts to distribute the flow evenly, as the chance of
flow skewing to one queue is high.

Example failures:

 # Check failed 5288 < 7000 traffic on main context (1/2): [2727, 2561, 8961, 6648]
not ok 1 rss_ctx.test_rss_context_overlap

 # Check failed 6710 < 7000 traffic on main context (2/2): [9280, 5217, 5358, 1352]
not ok 1 rss_ctx.test_rss_context_overlap

Ran test_rss_context_overlap and test_rss_context_overlap2
over 1,000 consecutive runs with no failures.

Signed-off-by: Zinc Lim <limzhineng2@gmail.com>
---
 tools/testing/selftests/drivers/net/hw/rss_ctx.py | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/drivers/net/hw/rss_ctx.py b/tools/testing/selftests/drivers/net/hw/rss_ctx.py
index f36f76d6ca59..5b25fa89c629 100755
--- a/tools/testing/selftests/drivers/net/hw/rss_ctx.py
+++ b/tools/testing/selftests/drivers/net/hw/rss_ctx.py
@@ -651,9 +651,14 @@ def test_rss_context_overlap(cfg, other_ctx=0):
         ntuple = defer(ethtool, f"-N {cfg.ifname} delete {ntuple_id}")
 
     # Test the main context
-    cnts = _get_rx_cnts(cfg)
-    GenerateTraffic(cfg, port=port).wait_pkts_and_stop(20000)
-    cnts = _get_rx_cnts(cfg, prev=cnts)
+    attempts = 3
+    for attempt in range(attempts):
+        cnts = _get_rx_cnts(cfg)
+        GenerateTraffic(cfg, port=port).wait_pkts_and_stop(20000)
+        cnts = _get_rx_cnts(cfg, prev=cnts)
+        if sum(cnts[:2]) >= 7000 and sum(cnts[2:4]) >= 7000:
+            break
+        ksft_pr(f"Skewed queue distribution, attempt {attempt + 1}/{attempts}: " + str(cnts))
 
     ksft_ge(sum(cnts[ :4]), 20000, "traffic on main context: " + str(cnts))
     ksft_ge(sum(cnts[ :2]),  7000, "traffic on main context (1/2): " + str(cnts))
-- 
2.53.0-Meta