HPROF viewer - faster load - feature proposition

Questions about YourKit Java Profiler
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Pasq
Posts: 4
Joined: Tue May 25, 2021 10:52 am

HPROF viewer - faster load - feature proposition

Post by Pasq »

I often use Java Profiler for analyzing HeapDumps in HPROF format. What is really inconvenient to me is that "Loading snapshot" and "Performing final tasks" happen every load. It would be nice to have an option to store result of that phases on disk, so next load of the same file is faster then the first load. (it is disk consuming approach, so it would be nice for user to decide if he wants to use it)

Eclipse MAT has such a feature, first load is very long, but every following is super fast.
Anton Katilin
Posts: 6172
Joined: Wed Aug 11, 2004 8:37 am

Re: HPROF viewer - faster load - feature proposition

Post by Anton Katilin »

Hello,

Thank you for the suggestion.

The profiler currently stores the dominator tree in a file .idom alongside the snapshot file. It is calculated on the first load and then reused on reopening the same snapshot. This saves significant part of snapshot opening time on subsequent openings.

Just curious, how often do you reopen snapshots? How long does it take to open a typical snapshot in your case?

Best regards,
Anton
Pasq
Posts: 4
Joined: Tue May 25, 2021 10:52 am

Re: HPROF viewer - faster load - feature proposition

Post by Pasq »

With idom files (uncompressed size):
- ~4GB dumps - around 1 minute 10 seconds
- ~12G dumps - around 9 minutes
Those are sizes I usually open.

How often do I reopen? I believe for each HPROF file:
- 1 time to diagnose memory leak / huge heap consumption
- 3-4 times to share the knowledge after finding the problem

There are dumps that I opened more then 20 times (when I train people with heap dump analysis).

The most annoying case is when I accidentally close snapshot :) (it can be done with simple CTRL+W)
Anton Katilin
Posts: 6172
Joined: Wed Aug 11, 2004 8:37 am

Re: HPROF viewer - faster load - feature proposition

Post by Anton Katilin »

Thanks for sharing the detail.

Would you be able to zip and send attached to [email protected] some profiler UI log files <user home>/.yjp/log/profile-ui-<pid>.log from your machine?
Pasq
Posts: 4
Joined: Tue May 25, 2021 10:52 am

Re: HPROF viewer - faster load - feature proposition

Post by Pasq »

Done.
Anton Katilin
Posts: 6172
Joined: Wed Aug 11, 2004 8:37 am

Re: HPROF viewer - faster load - feature proposition

Post by Anton Katilin »

Thank you. We'll review the logs.
Pasq
Posts: 4
Joined: Tue May 25, 2021 10:52 am

Re: HPROF viewer - faster load - feature proposition

Post by Pasq »

Hi, any update on that feature?
Anton Katilin
Posts: 6172
Joined: Wed Aug 11, 2004 8:37 am

Re: HPROF viewer - faster load - feature proposition

Post by Anton Katilin »

Hi,

No additional caching to speed up the snapshot reopening process has been implemented so far. The feature would require some non trivial changes, I hope we'll be able to afford them a future version.
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