i got it working - allthough it was not really straight forward.
first of all i have to make some corrections to my previous statements - just to be on the same level.
In the Cloud Service there are several Virtual Machines, each hosting either a WebRole Instance or a WorkerRole Instance.
Thus on a single VM only a single w3wp runs or no w3wp at all but a waworkerhost process.
In my special case there is the possiblity to have two w3wp running on a single VM. so i needed to differenciate between those two - thus requiering me to make some sort of process-Instance association.
What i wanted to log was: The Total CPU Load of a single VM, the CPU Load of the Instance Process running on the VM ( w3wp, waworkerhost).
The PerformanceCounter for Total CPU Load is easy and equal for each VM: \Processor(_Total)\% Processortime
for the webrole VM i couldnt just use the \process(w3wp)\% processortime counter because i can not be sure if its the correct w3wp ( see above)
Now here is what i did:
Since you have to start a performance counter monitor for each role instance OnStart() in the WebRole.cs or WorkerRole.cs i figured this is the only place where i can somehow gather the required information.
In the WorkerRole.cs i did:
int pc = Environment.ProcessorCount;
string instance = RoleEnvironment.CurrentRoleInstance.Id;
SomeOtherManagementClass.StartDiagnosticMonitorService(pc, instance, Process.GetCurrentProcess());
In the WebRole.cs the CurrentProcess also returns WaWorkerHost, so i had to move the above codelines into the global.asax of the WebRole . Here the correct Process is available.
In the SomeOtherManagementClass i put the StartDiagnosticsMonitorService , which now receives the CurrentProcess from which StartDiagnosticsMonitorService was called.
(from workerrole.cs it would receive WaWorkerHost Process and from WebRoles the w3wp process - including PID)
public static void StartDiagnosticMonitorService(int coreCount, string currentRole, Process process)
{
string processName = GetProcessInstanceName(process.Id);
SetCPUCoreData(coreCount, currentRole, processName, process.Id);
...
instanceProcessLoadCounterName = String.Format(@"\Process({0})\% Processor Time", processName);
}
GetProcessInstanceName(process.Id) is now called on each VM and gets the processName to the provided process.Id - this allows you to make a differentiation between multiple w3wps on a single VM because the instanceNames returned are w3wp, w3wp#1, w3wp#2 etc. in contrary to to the processName provided by GetCurrentProcess, which is allways w3wp. for this i modified a codesample i found here on stackoverflow - you can find it below:
private static string GetProcessInstanceName(int pid)
{
PerformanceCounterCategory cat = new PerformanceCounterCategory("Process");
string[] instances = cat.GetInstanceNames();
foreach (string instance in instances)
{
try
{
using (PerformanceCounter cnt = new PerformanceCounter("Process",
"ID Process", instance, true))
{
int val = (int)cnt.RawValue;
if (val == pid)
{
return instance;
}
}
}
catch (InvalidOperationException)
{
//this point is reached when a process terminates while iterating the processlist- this it cannot be found
}
}
return "";
}
Last but not least: SetCPUCoreData(coreCount, currentRole, processName, process.Id) saves all the relevant Data of the processes to the azure storage so it is available from everywhere in the application:
private static void SetCPUCoreData(int count, string roleinstance, string processName, int processID)
{
string[] instances = roleinstance.Split('.');
CloudStorageAccount storageAccount = CloudStorageAccount.Parse(GetSettingValue("LoadMonitor.Connection.String"));
CloudTableClient cloudTableClient = storageAccount.CreateCloudTableClient();
const string tableName = "PerformanceMonitorCoreCount";
cloudTableClient.CreateTableIfNotExist(tableName);
TableServiceContext serviceContext = cloudTableClient.GetDataServiceContext();
PerformanceCounterCPUCoreEntity ent = new PerformanceCounterCPUCoreEntity(count, instances[instances.Count() - 1],processName, processID);
serviceContext.AttachTo(tableName, ent);
serviceContext.UpdateObject(ent);
serviceContext.SaveChangesWithRetries(SaveChangesOptions.ReplaceOnUpdate);
}
the PerformanceCounterCPUCoreEntity is a Template for the StorageTable - look into the azure Storage API if you have any questions regarding this part, or just ask.
