Is there a way to determine/calculate the values of all of the memory usages that a Java program is using during runtime, and to continue to calculate them every so often? I am trying to create a visual representation of the total memory being used in a program and display it on some sort of chart or line graph, and continue to update the graph periodically for a project I am currently working on.
I've seen other questions that ask to view the memory and people have suggested VisualVM, but I do not just want to see the memory being used, but actually use the values of the memory used. (Does VisualVM do that?)
As a side question, is it possible to see how much memory a particular thread in the code is using, or can I only view the overall usage?
You can try
VisualVM . It
is a visual tool integrating several commandline JDK tools and lightweight profiling capabilities. Designed for both production and development time use, it further enhances the capability of monitoring and performance analysis for the Java SE platform.
Related
I am looking for a Java code profiler which I can use to profile my application (its a service which runs in backend) on production (so means low over head, and it must not slow down my application). Primarily I want calling tree profiling, that is if a() calls b() and then b() calls c(), then how much time a() b() and c() took, both inclusively and exclusively.
Have seen jvisualvm and jprofiler, but this is not what I am looking for, because I cannot tie my production application to them as it will cause a major performance issue.
Also, I did go through metrics (https://github.com/dropwizard/metrics), but it does not give me a functionality to profile the calling tree.
Callgrind (http://valgrind.org/docs/manual/cl-manual.html) type library is what I need, as it gives calling tree profiling functionality and advanced options like avoiding calling cycles (recursion). But I am not sure that Callgrind can be used on production as it dumps data when program terminates.
Can anyone suggest good calling tree profiler for java that can be used on production without compromising the performance?
Take a look at Java Mission Control in conjunction with Flight Recorder. Starting with the release of Oracle JDK 7 Update 40 (7u40), Java Mission Control is bundled with the HotSpot JVM, so it is highly integrated and purports to have small effects on run-time performance. I have only just started looking at it, and I do see some call tree functionality.
In general you don't (or I won't recommend) profilers that instrument your application. Instrumenting always means an uncontrollable production overhead.
What you can use is a sampling profiler. A sampling profiler makes a snapshot of the stack traces at a controllable interval. What you don't get is call counts, but, after some runtime, you get a good overview where you have hotspots. Since you can adjust the sample interval of the profiler you can influence the overhead of it.
A usable sampling profiler is shipped with the JDK, see the hprof page in the java 7 documentation.
In former times there existed some graphical analysis tools for the hprof cpu traces (not the heap traces). Now they are gone. However, you can already work with the generated text file.
I took a quick look on the Java Mission Control stuff mentioned above. I think it is quite mighty and will satisfy a lot of needs, in the white paper they say it has only 2% overhead. However, it is not totally what I personally need or want. For my applications it is better to have a "light" profiling enabled all the time.
Intel Amplifier XE http://software.intel.com/en-us/intel-vtune-amplifier-xe has got low overhead if any noticeable. It uses stack sampling technology to minimize the impact and it can attach and detach to running non-stop processes in production. You even do not need to have sources during profiling, you can dive into sources later after offline performance results browsing.
I don't know of any tool which can do profiling without an impact on performance.
You could add logging to the methods that you're interested in. Make sure you include the time stamp in the log; then you can do the timing. You should also configure the logging framework to log asynchronously to reduce the performance loss.
A load time weaver like AspectJ is able to add these calls at runtime, which would allow you to easily select the methods you want to monitor without changing the source code all the time.
Using an around aspect, you can even add timing logging, so you don't have to parse the logs and try to find matching log entries. See this blog post for details.
Have a look at perfspy (tutorial), it might already do out of the box what you need.
Related:
How to use AOP with AspectJ for logging?
http://mathewjhall.wordpress.com/2011/03/31/tracing-java-method-execution-with-aspectj/
http://www.jroller.com/holy/entry/injecting_timing_aspect_into_junit
The (relatively) new built-in performance monitor/profiler for Java is Mission Control. The Oracle docs advertise that they can be used in production without incurring performance hits (less than 2%):
The tool chain [Mission Control + Flight Recorder] enables developers and administrators to collect and analyze data from Java applications running locally or deployed in production environments.
I have used jvisualvm (VisualVM) for many years now, but never in a production environment due to the putative admonishment that it does incur performance overhead.
So I ask: What is so different between Mission Control (and its Flight Recorder) and VisualVM that allows MC/FR to not hinder performance? Or do they not include certain features/capabilities that VisualVM delivers?
The main performance difference in the method profiling is that MC/JFR uses sampling, and only samples a few threads per sampling interval. It uses a similar approach to AsyncGetCallTrace (see for example http://psy-lob-saw.blogspot.com/2016/06/the-pros-and-cons-of-agct.html)
Since I work with MC/JFR, I'm not as familiar with how VisualVM does it's sampling profiling, but I believe it's not using the same method.
MC/JFR has it's data gathering engine deeply integrated into the HotSpot JVM, VisualVM uses external APIs/MXBeans. This also helps JFR to lower the performance overhead.
Generally, JFR is designed to find the hot spots, rather than gathering data that 100% correct but might slow your application down and affect the actual behavior. This goes for both the method and allocation sampling, as well as other information about latency events (wait/sleep/block), where only the events above a certain threshold are recorded. I'm less familiar with how this compares for VisualVM.
Other than that, the two tools have different feature sets, none of which is a superset of the other.
I am looking for a Java code profiler which I can use to profile my application (its a service which runs in backend) on production (so means low over head, and it must not slow down my application). Primarily I want calling tree profiling, that is if a() calls b() and then b() calls c(), then how much time a() b() and c() took, both inclusively and exclusively.
Have seen jvisualvm and jprofiler, but this is not what I am looking for, because I cannot tie my production application to them as it will cause a major performance issue.
Also, I did go through metrics (https://github.com/dropwizard/metrics), but it does not give me a functionality to profile the calling tree.
Callgrind (http://valgrind.org/docs/manual/cl-manual.html) type library is what I need, as it gives calling tree profiling functionality and advanced options like avoiding calling cycles (recursion). But I am not sure that Callgrind can be used on production as it dumps data when program terminates.
Can anyone suggest good calling tree profiler for java that can be used on production without compromising the performance?
Take a look at Java Mission Control in conjunction with Flight Recorder. Starting with the release of Oracle JDK 7 Update 40 (7u40), Java Mission Control is bundled with the HotSpot JVM, so it is highly integrated and purports to have small effects on run-time performance. I have only just started looking at it, and I do see some call tree functionality.
In general you don't (or I won't recommend) profilers that instrument your application. Instrumenting always means an uncontrollable production overhead.
What you can use is a sampling profiler. A sampling profiler makes a snapshot of the stack traces at a controllable interval. What you don't get is call counts, but, after some runtime, you get a good overview where you have hotspots. Since you can adjust the sample interval of the profiler you can influence the overhead of it.
A usable sampling profiler is shipped with the JDK, see the hprof page in the java 7 documentation.
In former times there existed some graphical analysis tools for the hprof cpu traces (not the heap traces). Now they are gone. However, you can already work with the generated text file.
I took a quick look on the Java Mission Control stuff mentioned above. I think it is quite mighty and will satisfy a lot of needs, in the white paper they say it has only 2% overhead. However, it is not totally what I personally need or want. For my applications it is better to have a "light" profiling enabled all the time.
Intel Amplifier XE http://software.intel.com/en-us/intel-vtune-amplifier-xe has got low overhead if any noticeable. It uses stack sampling technology to minimize the impact and it can attach and detach to running non-stop processes in production. You even do not need to have sources during profiling, you can dive into sources later after offline performance results browsing.
I don't know of any tool which can do profiling without an impact on performance.
You could add logging to the methods that you're interested in. Make sure you include the time stamp in the log; then you can do the timing. You should also configure the logging framework to log asynchronously to reduce the performance loss.
A load time weaver like AspectJ is able to add these calls at runtime, which would allow you to easily select the methods you want to monitor without changing the source code all the time.
Using an around aspect, you can even add timing logging, so you don't have to parse the logs and try to find matching log entries. See this blog post for details.
Have a look at perfspy (tutorial), it might already do out of the box what you need.
Related:
How to use AOP with AspectJ for logging?
http://mathewjhall.wordpress.com/2011/03/31/tracing-java-method-execution-with-aspectj/
http://www.jroller.com/holy/entry/injecting_timing_aspect_into_junit
I want to measure the level of CPU and memory utilisation of a java program, preferably with a GUI and graphs showing exact utilisation levels throughout the period of execution of the program.
Is there a library/framework that does this?
Also, i would prefer if I could measure such usage for a program(either desktop or web app) that runs on local system or remote machine.
You can use Eclipse TPTP : http://www.eclipse.org/tptp/
It contains very good tools to follow the threads as well as the memory and cpu consumption, all inside a clear GUI. As every java profiler, it can be configured to follow a remote java program.
If you're using Eclipse as your IDE, this is a natural choice.
JProfiler is good to start with. You can connect it to a local or a remote java process and profile the application to understand the memory usage and various other performance counters.
I'd say VisualVM will be a good start.
Also try VisualVM, it's absolutely and free bundled in oracle jdk(don't know about openjdk).
I had an old application, a JAR file, that went through some enhancements. Basically some parts of the code had to be modified along with modifying some of the logic.
Comparing the OLD version against the NEW version, the NEW version is about 2X slower than the old one.
I'm trying to narrow down whats causing the slow down, but I'm finding myself measuring the time for certain for-loops using System.println with System.currentTimeMillis(). This is really getting very tedious.
Is there a Java performance tool that will help me in figuring out why the NEW JAR is about 2X slower than the old one?
Thanks in advance.
JProfiler has the capability to compare CPU snapshots. Record the execution for the old and the new JAR file and save snapshots (if the JVM exits at the end, configure a "JVM exit" trigger that saves a snapshot).
Then open the snapshot comparison window with "Session->Compare Snapshots in New Window" and add the two snapshot. A hot spots comparison will look like this (a view filter is set in this case):
It will immediately show you which methods are responsible for the increase in execution time.
Another way to analyze the differences in execution time is the call tree comparison which will look like this:
Disclaimer: My company develops JProfiler.
You should use a profiler. This will show you which methods are taking the most time (and what is calling them), without you having to guess which ones to measure.
Java comes with a built-in profiler called hprof, but see also:
https://stackoverflow.com/questions/14762/please-recommend-a-java-profiler
5 things you didn't know about ... Java performance monitoring
The JConsole and VisualVM tools
Depending on how long-running the process is, I'd think about Visual VM 1.3.3. If you download all the plugins, you'll be able to see heap, threads, objects, etc. That ought to help, and it won't cost a dime.
I believe it assumes the Oracle/Sun JVM.
A profiler tool like YourKit or something to measure performance reliably like Hyperic's Sigar is a good canditate for your case. Have a look at those tools.
The former will find bottlenecks in your code and/or memory leaks (not all of them) while as the latter is an API that you can measure performance reliably since Oracle's JVM & OpenJDK have no way of getting perfomance metrics reliably/consistently/accurately (like CPU wall clock time or CPU time spent from the application, memory usage, application threads, etc).
By default, Java provides packages for these things.
For example:
java.lang.management.ManagementFactory
java.lang.management.ThreadMXBean
but depending on your case they may or may not be adequate (keep in mind they are OK for most cases unless we are talking about something critical).