Can't open a 3GB CPU Tracing snapshot even with Xmx12GB

Questions about YourKit Java Profiler
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dantewang
Posts: 4
Joined: Wed Nov 19, 2014 6:11 am

Can't open a 3GB CPU Tracing snapshot even with Xmx12GB

Post by dantewang »

I use profile comparison a lot. However, after upgrading to 2014, I can't open larger profile to compare.

For example, I can't open a 3GB cpu tracing snapshot when I give yjp 12GB heap -- getting "out of memory" error.

With 12GB heap, I can only open two profiles, each 1.2GB, to compare.

With previous version, I can easily compare two profile snapshots as long as the total size is smaller than the heap size of yjp.
Anton Katilin
Posts: 6172
Joined: Wed Aug 11, 2004 8:37 am

Re: Can't open a 3GB CPU Tracing snapshot even with Xmx12GB

Post by Anton Katilin »

Hi,

We have indeed changed storage location for CPU tracing (and some other) data from native memory to Java heap in UI in order to improve processing speed. As the result, it may now require setting bigger -Xmx when working with such huge performance (!) snapshot.

Please set -Xmx even bigger if you experience such OutOfMemoryException.

Anyway, could you please share the problematic snapshot file(s). We'll try to find out whether we could make any optimizations to reduce the memory footprint. If possible, could you please zip the snapshot(s), upload to DropBox or similar and send the download link to [email protected]

Best regards,
Anton
dantewang
Posts: 4
Joined: Wed Nov 19, 2014 6:11 am

Re: Can't open a 3GB CPU Tracing snapshot even with Xmx12GB

Post by dantewang »

Thanks Anton!

I have set Xmx to 14GB and I still can't open two 1.8GB snapshots at the same time. The machine has 16GB memory so I can't increase it more.

By the way, I was able to open snapshots with such size before on the same machine.

I will try to get a auto-generated hprof and upload it.
Anton Katilin
Posts: 6172
Joined: Wed Aug 11, 2004 8:37 am

Re: Can't open a 3GB CPU Tracing snapshot even with Xmx12GB

Post by Anton Katilin »

Hi,
I have set Xmx to 14GB and I still can't open two 1.8GB snapshots at the same time. The machine has 16GB memory so I can't increase it more.
Lack of physical memory is not a problem: virtual memory will do its job.
By the way, I was able to open snapshots with such size before on the same machine.
As I wrote, there was a change in version 2014 which increased the profiler UI's memory use for loading tracing results. The change makes UI faster, and the memory increase for most snapshots is just negligible. In other words, it's a good change for 99% users. However, in those rare cases when performance snapshots are really huge (normally, their size is a few megabytes only; in contrast to memory snapshots their size does not correlate with the size of heap) users should increase the profiler UI's -Xmx until the snapshots eventually fit.
I will try to get a auto-generated hprof and upload it.
Thank you. Additionally (or instead) I would ask you to provide the snapshot file itself. If you can't share the snapshot please send at least the profiler log files from <user home>/.yjp/log

Best regards,
Anton
Anton Katilin
Posts: 6172
Joined: Wed Aug 11, 2004 8:37 am

Re: Can't open a 3GB CPU Tracing snapshot even with Xmx12GB

Post by Anton Katilin »

An update: we've made an optimization to reduce memory footprint of loaded CPU profiling records. It will be available in the first EAP build of the next version.

Best regards,
Anton
Anton Katilin
Posts: 6172
Joined: Wed Aug 11, 2004 8:37 am

Re: Can't open a 3GB CPU Tracing snapshot even with Xmx12GB

Post by Anton Katilin »

Hi,

Early access build is now available:
http://www.yourkit.com/eap

Best regards,
Anton
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