testing: log the CPU serial number in the router benchmark.

This is done as an attempt at detecting live migration.

acceptance/router_benchmark/test.py

@@ -20,7 +20,7 @@
 
 from collections import namedtuple
 from plumbum import cli
-from plumbum.cmd import docker, whoami, lscpu
+from plumbum.cmd import docker, whoami, lscpu, grep
 from plumbum import cmd
 
 from acceptance.common import base
@@ -417,7 +417,6 @@ def run_test_case(self, case: str, mapArgs: list[str]) -> (int, int):
 
         output = self.exec_br_load(case, mapArgs, 10000000)
         for line in output.splitlines():
-            print(line)
             if line.startswith("metricsBegin"):
                 _, beg, _, end = line.split()
 
@@ -519,6 +518,10 @@ def _run(self):
         # gets much lower performance.
         self.exec_br_load(list(TEST_CASES)[0], mapArgs, 3000000)
 
+        # Record the CPU serial in an attempt at detecting live migrations.
+        logger.info("CPU serial BEFORE: "
+                    f'{(cmd.sudo["-A", "dmidecode", "-t", "processor"] | grep["ID:"])().strip()}')
+
         # At long last, run the tests
         rateMap = {}
         droppageMap = {}
@@ -527,6 +530,9 @@ def _run(self):
             rateMap[testCase] = processed
             droppageMap[testCase] = dropped
 
+        logger.info("CPU serial AFTER: "
+                    f'{(cmd.sudo["-A", "dmidecode", "-t", "processor"] | grep["ID:"])().strip()}')
+
         self.log_core_counts()
 
         # Log and check the performance...