Update Linux VM metadata to:

1. Always show the kernel command line
2. Show if RT kernel was enabled

PiperOrigin-RevId: 846435753

Author: pmkc

perfkitbenchmarker/linux_virtual_machine.py

@@ -1200,11 +1200,13 @@ def RecordAdditionalMetadata(self):
     self.os_metadata['kernel_release'] = str(self.kernel_release)
     self.os_metadata['cpu_arch'] = self.cpu_arch
     self.os_metadata.update(self.partition_table)
+    self.os_metadata['kernel_command_line'] = self.kernel_command_line
     if FLAGS.append_kernel_command_line:
-      self.os_metadata['kernel_command_line'] = self.kernel_command_line
       self.os_metadata['append_kernel_command_line'] = (
           FLAGS.append_kernel_command_line
       )
+    if _ENABLE_RT_KERNEL.value:
+      self.os_metadata['enable_rt_kernel'] = True
     # TODO(pclay): consider publishing full lsmod as a sample. It's probably too
     # spammy for metadata
     if _KERNEL_MODULES_TO_ADD.value:

tests/linux_virtual_machine_test.py

@@ -521,6 +521,7 @@ class LinuxVirtualMachineTestCase(pkb_common_test_case.PkbCommonTestCase):
           pkb_common_test_case.IP_LINK_TEXT
       ),
       'cat /proc/cpuinfo | grep processor | wc -l': '16',
+      'cat /proc/cmdline': 'test kernel flags'
   }
 
   def CreateVm(
@@ -687,6 +688,7 @@ def testBoot(self):
         'os_info': self.os_info,
         'cpu_arch': self.cpu_arch,
         'threads_per_core': 1,
+        'kernel_command_line': 'test kernel flags',
     }
     self.assertEqual(expected_os_metadata, vm.os_metadata)