System.Diagnostics.PerformanceCounter NextValue(): why so slow?

Question

Hi All,

I'm finding that calling NextValue() on a PerformanceCounter is extremely slow.  I say slow, because when I add the exact same counters (as my code uses) to perfmon, the sampling takes place every second without issue.  To sample the same set of counters (instances of the Thread/Processor Time counter), my code takes 40 seconds+.

My code, in its simplest form, is doing this:

        private void Foo()

        {

            PerformanceCounter c = new PerformanceCounter();



            c.MachineName = "AServer";

            c.CategoryName = "Thread";

            c.CounterName = "% Processor Time";



            foreach (instance k in col) //about 60ish...

            {

                c.InstanceName = k.InstanceName;

                c.NextValue(); //is assigned to simple var

            }

        }

(And yes, I realise I should be calling NextValue twice initially).

As I mentioned, the same set of 60ish counters in perfmon sample quite happily.  Am I doing something stupid, or is there a quicker way to "batch" sample instances?

Thanks,
Rob

Answer 1

Really, no one has run into the same issue?

Does anyone know how to efficiently sample multiple instances - is there a way to "batch sample" several instances in the way that perfmon does?

Thanks,
Rob

Answer 2

Hello, Robert
What's your version of your .net framework? .Net Framework 1.1 has a performance issue when your run multi-thread instance. For 2.0 upper, Could you elaborate more about your code? I did not face this issue on my PC.
Thanks
Chao

Answer 3

Hi Chao,

I'm running it on vista on .net 3.5.

When I add the instances in perfrmon, they update quite happily every second (all 60).  Whereas in my code (as per above) as I need to call .NextValue() for each of the 60 instances, it crawls - the completion of the foreach loop takes 30- 40 seconds.

I really only notice this if I'm trying to connect/run the code on remote servers with high latency.

Cheers,
Rob