Profiling Your App

When you load test your application with Test Studio, the Load Testing tool automatically calculates metrics about the HTTP traffic it receives from your application server. But some of the most important data about your application's performance comes from directly observing performance counters on the application and database servers. Test Studio's Execution Server and Standalone versions provide a Profiler for the machine where they are installed. By adding a machine to a Test Studio Load Test under Monitor Performance, you can gather robust information about the performance of any machine in your application topology.

Identifying Metrics

You may select which performance metrics to gather and analyze in a number of ways.

Requirements

Project stakeholders may provide you with requirements that directly correspond to specific performance metrics. For example, the application may have a requirement that it must support over 1000 simultaneous users. This corresponds to a stress test in which the total number of virtual users surpasses 1000.

Derived metrics

You can also derive specific metrics from your application requirements. For example, the application may have a requirement that users begin to see responses to their actions within one second on average. From this requirement, you can derive a goal: "Average Time to First Byte is Less Than 1000 ms."

Role-specific Metrics

Depending on the specific role of a machine in your application topology, you can select a different set of performance counters to monitor during your load test. Because every application has its own distinct architecture, each load test may have its own set of appropriate performance counters. Talk to your developers about which performance counters are most relevant for your application. Consider these as a starting point.

Application Server

Consider monitoring these performance counters to measure the resource usage of different components of the application server.

Memory\ Available bytes
Memory\ Cache Faults/sec
Processor\ % Processor Time
Physical Disk\ Avg. Disk Read Queue Length
Network Interface\ TCP Connection Failures
Server\ Bytes Transmitted/sec

For .NET applications, consider monitoring these .NET performance counters:

.NET CLR LocksAndThreads\ Global\ Contention Rate /sec
.NET CLR LocksAndThreads\ Global\ Queue Length / sec
.NET CLR Memory\ # Bytes in all Heaps
.NET CLR Memory\ % Time in GC

Database Server

Consider monitoring these performance counters to measure the behavior and resource usage of your SQL database server.

Buffer Manager\ Buffer Cache Hit Ratio
Buffer Manager\ Page life expectancy
SQL Statistics\ Batch Requests/sec
SQL Statistics\ SQL Compilations/sec
Locks\ Lock Waits/sec: _Total
General Statistics\ Processes Block
Databases\ Active Transactions

Execution Server

Consider monitoring these performance counters to determine if your Execution Server is a bottleneck in your load test.

Memory\ Available bytes
Processor\ % Processor Time
Network Interface\ Bytes Received/sec
.NET CLR LocksAndThreads\ Telerik.TestStudio.RemoteExecutor \ ContentionRate /sec