LoadRunner Part # 4 - Performance Parameters

Performance Parameters Monitored

The basic parameters monitored during performance testing include:

• Processor Usage - amount of time processor spends executing non-idle threads.
• Memory use - amount of physical memory available to processes on a computer.
• Disk time - amount of time disk is busy executing a read or write request.
• Bandwidth - shows the bits per second used by a network interface.
• Private bytes - number of bytes a process has allocated that can't be shared amongst other processes. These are used to measure memory leaks and usage.
• Committed memory - amount of virtual memory used.
• Memory pages/second - number of pages written to or read from the disk in order to resolve hard page faults. Hard page faults are when code not from the current working set is called up from elsewhere and retrieved from a disk.
• Page faults/second - the overall rate in which fault pages are processed by the processor. This again occurs when a process requires code from outside its working set.
• CPU interrupts per second - is the avg. number of hardware interrupts a processor is receiving and processing each second.
• Disk queue length - is the avg. no. of read and write requests queued for the selected disk during a sample interval.
• Network output queue length - length of the output packet queue in packets. Anything more than two means a delay and bottlenecking needs to be stopped.
• Network bytes total per second - rate which bytes are sent and received on the interface including framing characters.
• Response time - time from when a user enters a request until the first character of the response is received.
• Throughput - rate a computer or network receives requests per second.
• Amount of connection pooling - the number of user requests that are met by pooled connections. The more requests met by connections in the pool, the better the performance will be.
• Maximum active sessions - the maximum number of sessions that can be active at once.
• Hit ratios - This has to do with the number of SQL statements that are handled by cached data instead of expensive I/O operations. This is a good place to start for solving bottlenecking issues.
• Hits per second - the no. of hits on a web server during each second of a load test.
• Rollback segment - the amount of data that can rollback at any point in time.
• Database locks - locking of tables and databases needs to be monitored and carefully tuned.
• Top waits - are monitored to determine what wait times can be cut down when dealing with the how fast data is retrieved from memory
• Thread counts - An applications health can be measured by the no. of threads that are running and currently active.
• Garbage collection - has to do with returning unused memory back to the system. Garbage collection needs to be monitored for efficiency.

Performance Test Tools

There are a wide variety of performance testing tools available in market. The tool you choose for testing will depend on many factors such as types of protocol supported , license cost , hardware requirements , platform support etc. Below is a list of popularly used testing tools.

• HP Loadrunner - is the most popular performance testing tools on the market today. This tool is capable of simulating hundreds of thousands of users, putting applications under real life loads to determine their behavior under expected loads. Loadrunner features a virtual user generator which simulates the actions of live human users.
• HTTP Load - a throughput testing tool aimed at testing web servers by running several http or https fetches simultaneously to determine how a server handles the workload.
• Proxy Sniffer - one of the leading tools used for load testing of web and application servers. It is a cloud based tool that's capable of simulating thousands of users. Summary