fix: new intermittent ci issue

While running AB perf tests with new kvm_metrics enabled
a new sock intermittent ci issues was found and ping_latency
showed a regression.
vsock iperf test fails intermittently with error:
`/tmp/iperf3-vsock: Text file busy`
ping_latency regression was not consistent and fixed on retry.
Since the only variable here is collecting metrics
adjusting the point of collection for final metrics for
performance tests fixes both the issues.

Signed-off-by: Sudan Landge <[email protected]>

Author: Sudan Landge

tests/integration_tests/performance/test_network_ab.py

@@ -96,10 +96,10 @@ def test_network_latency(network_microvm, metrics, iteration):
         assert rc == 0, stderr
 
         samples.extend(consume_ping_output(ping_output))
+    fcmetrics.stop()
 
     for sample in samples:
         metrics.put_metric("ping_latency", sample, "Milliseconds")
-    fcmetrics.stop()
 
 
 class TcpIPerf3Test(IPerf3Test):

tests/integration_tests/performance/test_vsock_ab.py

@@ -110,5 +110,5 @@ def test_vsock_throughput(
     test = VsockIPerf3Test(vm, mode, payload_length)
     data = test.run_test(vm.vcpus_count + 2)
 
-    emit_iperf3_metrics(metrics, data, VsockIPerf3Test.WARMUP_SEC)
     fcmetrics.stop()
+    emit_iperf3_metrics(metrics, data, VsockIPerf3Test.WARMUP_SEC)