How do you out effects of YourKit on trends

Questions about YourKit Java Profiler
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Michael.Scaman
Posts: 34
Joined: Mon Feb 02, 2015 3:14 pm

How do you out effects of YourKit on trends

Post by Michael.Scaman »

If we see a trend like a growth of heap allocation, is there a way of ruling out whether the growth in memory or cpu use is the process of collection through YourKit or the application being monitored?

Is there a way to un attach YourKit and restart it fresh, for example, leaving the target running to try and rule out YourKit adding to the trend?
Anton Katilin
Posts: 6172
Joined: Wed Aug 11, 2004 8:37 am

Re: How do you out effects of YourKit on trends

Post by Anton Katilin »

If you suspect the YourKit adds more profiling overhead than you expect, could you please provide detail on what profiling mode(s) you are using and what startup options specify.
a growth of heap allocation
YourKit does not allocate many objects, temporary in particular, in Java heap. The only exception, under certain circumstances, may be the built-in probes obtaining monitored object properties (e.g. SQL query or web request URL) via the object's interface methods, some of implementations of whose may involve temporary object creation. However, this may happen only when the probes are active, i.e. when profiling is running.
cpu use
Again, we need to know what kind of profiling you're using. Please read more about the profiling overhead and how to avoid it here:
https://www.yourkit.com/docs/java/help/overhead.jsp
Is there a way to un attach YourKit and restart it fresh, for example, leaving the target running to try and rule out YourKit adding to the trend?
You may simply start the profiled application with YourKit profiler agent with the startup options recommended for production (please use the EE sever integration wizard) and do not activate any profiling modes, to see how the profiled application performance differs from the performance of the same application running without the profiler at all. Normally, you should not notice any difference.
Michael.Scaman
Posts: 34
Joined: Mon Feb 02, 2015 3:14 pm

Re: How do you out effects of YourKit on trends

Post by Michael.Scaman »

I am using the cli and it is specifically an increase in heap allocation. This is cpu profiling.


############# set to cpu sampling ############################################

java -jar $YjpJarLocation $HostProfiled $PortProfiled start-cpu-sampling

sleep 15m

# stop monitors

# cpu only in this script
java -jar $YjpJarLocation $HostProfiled $PortProfiled stop-cpu-profiling
Anton Katilin
Posts: 6172
Joined: Wed Aug 11, 2004 8:37 am

Re: How do you out effects of YourKit on trends

Post by Anton Katilin »

Hi,

Some built-in probes are in Auto state by default, and start working when CPU sampling is started:
https://www.yourkit.com/docs/java/help/ ... probes.jsp

Please try to disable the probes with the agent startup option probe_off or probe_disable:
https://www.yourkit.com/docs/java/help/ ... sp#startup

Best regards,
Anton
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