diff --git a/python/tests/perf/nsys_kernel_probe.py b/python/tests/perf/nsys_kernel_probe.py
index 7d02aa09..0481a17d 100644
--- a/python/tests/perf/nsys_kernel_probe.py
+++ b/python/tests/perf/nsys_kernel_probe.py
@@ -19,8 +19,9 @@ n_streams, N, cdim, cap, batch = (int(a) for a in sys.argv[1:6])
 f = File(common.DATA_FILE)
 pd = File(common.PEDESTAL_FILE)
 
-cf = ClusterFinderCUDA((f.rows, f.cols), (cdim, cdim), n_sigma=common.N_SIGMA,
-                       max_clusters_per_frame=cap, n_streams=n_streams)
+cf = ClusterFinderCUDA((f.rows, f.cols), cluster_size=(cdim, cdim),
+                       n_sigma=common.N_SIGMA, max_clusters_per_frame=cap,
+                       n_streams=n_streams)
 for _ in range(common.N_PEDESTAL_FRAMES):
     cf.push_pedestal_frame(pd.read_frame().copy())
 
diff --git a/python/tests/perf/run_probes.py b/python/tests/perf/run_probes.py
index 17a07d85..7f6e4709 100644
--- a/python/tests/perf/run_probes.py
+++ b/python/tests/perf/run_probes.py
@@ -51,8 +51,11 @@ def run_one(cdim, cap, streams, label, n_frames, batch, outdir) -> dict | None:
     for line in p.stdout.splitlines():
         if line.strip().startswith(("n_streams", "H2D/frame", "wall")):
             print("   ", line.strip())
-    if not rep.with_suffix(".nsys-rep").exists():
-        print(f"    FAILED: {p.stderr.strip()[-400:]}")
+    # nsys writes a report even when the traced process crashes, and returns
+    # the child's exit code: check it, or a dead probe surfaces later as a
+    # missing CUPTI table in the export.
+    if p.returncode != 0 or not rep.with_suffix(".nsys-rep").exists():
+        print(f"    FAILED (exit {p.returncode}): {p.stderr.strip()[-400:]}")
         return None
 
     subprocess.run([common.NSYS, "stats", "--force-export=true", "--report",