I'm running some JMeter tests against a Java process to determine how responsive a web application is under load (500+ users). JMeter will give the response time for each web request, and I've written a script to ping the Tomcat Manager every X seconds which will get me the current size of the JVM heap.I'd like to collect stats on the server of the % of CPU being used by Tomcat. I tried to do it in a shell script using ps like this:PS_RESULTS=`ps -o pcpu,pmem,nlwp -p $PID`...running the command every X seconds and appending the results to a text file. (for anyone wondering, pmem = % mem usage and nlwp is number of threads)However I've found that this gives a different definition of "% of CPU Utilization" than I'd like - according to the manpages for ps, pcpu is defined as:cpu utilization of the process in "##.#" format. It is the CPU time used divided by the time the process has been running (cputime/realtime ratio), expressed as a percentage. In other words, pcpu gives me the % CPU utilization for the process for the lifetime of the process.Since I want to take a sample every X seconds, I'd like to be collecting the CPU utilization of the process at the current time only - similar to what top would give me(CPU utilization of the process since the last update). How can I collect this from within a shell script?
Thanks for dstat tool!