Hi Kevin,
this is fine. You already did the hard part – provide the content. I’ll update the help within MAT.
I anyway wanted to check if the description how to setup the tooling to do updates to the documentation is still accurate
and update it if needed.
Thanks for the help!
Krum
From: mat-dev-bounces@xxxxxxxxxxx [mailto:mat-dev-bounces@xxxxxxxxxxx]
On Behalf Of Kevin Grigorenko
Sent: Mittwoch, 9. November 2016 19:27
To: Memory Analyzer Dev list <mat-dev@xxxxxxxxxxx>
Subject: Re: [mat-dev] Refreshing MAT's web pages
Hey Krum, I've never setup the local DITA builds for help to test content changes, so I'm not very comfortable with that (and it looks like new topics will need
to be created) and a bit short on time these days, sorry
--
Kevin Grigorenko
IBM WebSphere Foundation SWAT Team
kevin.grigorenko@xxxxxxxxxx
Blog: https://www.ibm.com/developerworks/mydeveloperworks/blogs/kevgrig/
From: "Tsvetkov, Krum" <krum.tsvetkov@xxxxxxx>
To: Memory Analyzer Dev list <mat-dev@xxxxxxxxxxx>
Date: 11/09/2016 05:52 AM
Subject: Re: [mat-dev] Refreshing MAT's web pages
Sent by: mat-dev-bounces@xxxxxxxxxxx
Hi Kevin,
Thanks a lot for the quick update to the Wiki! These were very good changes.
I’ll try to catch up now with the HPROF part
J
Will you bring the changes also into the documentation (the help bundle)?
I could also do this if you like.
Krum
From:
mat-dev-bounces@xxxxxxxxxxx
[mailto:mat-dev-bounces@xxxxxxxxxxx]
On Behalf Of Kevin Grigorenko
Sent: Dienstag, 8. November 2016 20:55
To: Memory Analyzer Dev list <mat-dev@xxxxxxxxxxx>
Subject: Re: [mat-dev] Refreshing MAT's web pages
I submitted some proposed edits for the IBM section:
-
Used the most recent version of MAT+DTFJ to update the list of heap dump types
-
Removed the ancient information about 1.4.2
-
Added discussion about system dumps vs PHDs
-
Removed the reference to using MAT in IBM Support Assistant as we're moving away from that
System Dumps and Heap Dumps from IBM Virtual Machines
Memory Analyzer may read memory-related information from IBM system dumps and from Portable Heap Dump (PHD) files with the
IBM DTFJ feature installed. Once installed, then
File > Open Heap Dump should give the following options for the file types:
-
All known formats
-
HPROF binary heap dumps
-
IBM 1.4.2 SDFF
-
IBM Javadumps
-
IBM SDK for Java (J9) system dumps
-
IBM SDK for Java Portable Heap Dumps
For a comparison of dump types, see
Debugging from dumps. System dumps are simply operating system core dumps; therefore, they are a superset of portable heap dumps. System dumps are far superior than PHDs, particularly for more accurate GC roots, thread-based analysis, and unlike PHDs, system
dumps contain memory contents like HPROFs. Older versions of IBM Java (e.g. < 5.0SR12, < 6.0SR9) require running jextract on the operating system core dump which produced a zip file that contained the core dump, XML or SDFF file, and shared libraries. The
IBM DTFJ feature still supports reading these jextracted zips; however, newer versions of IBM Java do not require jextract for use in MAT since DTFJ is able to directly read each supported operating system's core dump format. Simply ensure that the operating
system core dump file ends with the .dmp suffix for visibility in the MAT Open Heap Dump selection. It is also common to zip core dumps because they are so large and compress very well. If a core dump is compressed with
.zip, the IBM DTFJ feature in MAT is able to decompress the ZIP file and read the core from inside (just like a jextracted zip). The only significant downsides to system dumps over PHDs is that they are much larger, they usually take longer to produce,
they may be useless if they are manually taken in the middle of an exclusive event that manipulates the underlying Java heap such as a garbage collection, and they sometimes require operating system configuration (Linux,
AIX) to ensure non-truncation.
In recent versions of IBM Java (> 6.0.1), by default, when an OutOfMemoryError is thrown, IBM Java
producesa system dump, PHD, javacore, and Snap file on the first occurrence for that process (although often the core dump is suppressed by the default 0 core ulimit on operating systems such as Linux). For the next three occurrences, it produces only a
PHD, javacore, and Snap. If you only plan to use system dumps, and you've configured your operating system correctly as per the links above (particularly core and file ulimits), then you may disable PHD generation with -Xdump:heap:none. For versions of IBM
Java older than 6.0.1, you may switch from PHDs to system dumps using -Xdump:system:events=systhrow,filter=java/lang/OutOfMemoryError,request=exclusive+prepwalk -Xdump:heap:none
In addition to an OutOfMemoryError, system dumps may be produced using operating system tools (e.g. gcore in gdb for Linux, gencore for AIX, Task Manager for Windows, SVCDUMP for z/OS, etc.), using the
IBM Java APIs, using the various options of
-Xdump, using
Java Surgery, and more.
Versions of IBM Java older than IBM JDK 1.4.2 SR12, 5.0 SR8a and 6.0 SR2 are known to produce inaccurate GC root information.
--
Kevin Grigorenko
IBM WebSphere Foundation SWAT Team
kevin.grigorenko@xxxxxxxxxx
Blog: https://www.ibm.com/developerworks/mydeveloperworks/blogs/kevgrig/
From: "Tsvetkov, Krum" <krum.tsvetkov@xxxxxxx>
To: Memory Analyzer Dev list <mat-dev@xxxxxxxxxxx>
Date: 11/08/2016 05:24 AM
Subject: [mat-dev] Refreshing MAT's web pages
Sent by: mat-dev-bounces@xxxxxxxxxxx
Hi,
A few days ago I started cleaning up the MAT web site and wiki pages. There were a number of broken links, outdated information, very old styling theme, etc …
I am not capable of creating a really good and modern looking page, therefore I focused on cleaning up broken stuff and trying to put some better structure.
Here is a summary of what changed so far:
- Updated the home page https://www.eclipse.org/mat/to
use similar styling as most of the other projects – the “solstice” theme. Again, it is not the super-good-looking page, but at least we are not two themes behind most of the other eclipse projects
- Used the navigation bar on the top, which comes with the new theme, to structure groups of links related to
developers/contributors, documentation, support. The info/links was available already before, but spread unstructured across our home page
- Removed the links to previous presentationsfrom the home page (the newest one was 2010), created a wiki page with the still working links, and linked it under documentation as additional learning material. They were a few links which didn’t
work any longer. For some I managed to find the replacement, the others I deleted.
If you happen to know some new tutorial or presentation which we could link – let me know. A couple of weeks ago I was at EclipseCon Europe and was pleasantly surprised to be in two sessions:
https://www.eclipsecon.org/europe2016/session/optimising-eclipse-plug-insand
https://www.eclipsecon.org/europe2016/session/performance-testing-budget.
- I removed the links to the webinars. The links to adobedev.adobe.acrobat.com are not responding any longer. I spend some time looking for new links to the old info, but found none. If anyone has an idea where to find them (e.g. the adobedev.adobe.acrobat.com/p76554151/
one) let me know.
- On the wiki (linked as Getting Started) I tried to keep the Getting started part minimal – install and a links to two (in my opinion) good first-reading materials.
Please have a look and let me know if you still find some broken links / wrong data! Suggestions for improvement are also welcome!
Some further changes I will try to do (and I need some help):
- On the wiki we still have a lengthy “Getting a Heap Dump” description
https://wiki.eclipse.org/MemoryAnalyzer#Getting_a_Heap_Dump.
This is pretty much the same as the one in the documentation within MAT, which is also available online:
http://help.eclipse.org/neon/topic/org.eclipse.mat.ui.help/tasks/acquiringheapdump.html.
In addition, both descriptions look quite outdated – they are mostly talking about java 1.4 to 1.6, there is java 8 beta mentioned on one place, there are some descriptions specific to MAT 1.2 and 1.3, etc… While most of the information is still correct, it
leaves the impression that the info is out-of-date
o I will try to update the description – add some details about java 8, remove the paragraphs about MAT 1.2, etc…
o I would appreciate if one of the IBM colleagues can check if the descriptions for using IBM dumps are still fine and update if necessary (also add new java versions to the list if needed)
o The open question is where to fix it – at the end I see no use in having the info maintained twice. I would like to have an up-to-date documentation within the tool, and have it also
online. The issue is, that with our release tempo, the next online version of the docu will be June 2017, and I’d like to have the update sooner than that. I am thinking about fixing both documentation and Wiki and then removing the Wiki once we have an online
version of the documentation which is up-to-date. If we manage to do improvements to the doc, we could probably
o Talking about java versions and heap dumps – we’ll have to watch how java 9 evolves and see if there are some changes relevant for MAT
- Another piece of documentation which needs to be refreshed is the contributor guide. I’d like to review it again and come up with an up-to-date description. This would need more time, so let’s see if I manage to get to it.
Feedback is welcome!
Krum
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