RFR (M) JDK-6479360 - detailed dumping of class size statistics
ioi.lam at oracle.com
Tue Jan 22 14:28:22 PST 2013
Thanks for the review. Please see my comments in-line
On Jan 22, 2013, at 2:07 PM, Karen Kinnear <karen.kinnear at oracle.com> wrote:
> Thank you for doing this. I like the way you have the size collection in the file
> with the metadata definitions.
> 1. diagnosticCommand.hpp line 200 - inspeactheap -> inspectheap
> 2. please update copyrights on all files you changed to 2013
> 3. I sent an email to the embedded folks to find out if they want this
> under INCLUDE_SERVICES.
> If they do ...
> - did you build with and without INCLUDE_SERVICES?
> What happens when you build with it off and run the jcmd ?
> I am confused that in diagnosticCommand.cpp ClassStatsDcmd is available without
> INCLUDE_SERVICES, but the actual details below the collect_statistics are not?
> Did you talk to the embedded team about whether they want this or not?
I did test without INCLUDE_SERVICE -- this was done by building JPRT on the hotspotwest, queue, which includes all the embedded SE builds (x86, ARM, PPC, etc) which turn off INCLUDE_ SERVICES.
> - I would recommend that include files also add the new methods conditional
> on INCLUDE_SERVICES - you did that in some of them, but I think you missed:
> method.hpp, methodData.hpp, constantPool.hpp, constMethod.hpp, annotations.hpp
Will do. I was trying to avoid clutter in the header files, but I think it's better to explicitly mark them by #ifdefs.
> 4. heapInspection.hpp line 56: is InstBytesi supposed to be InstBytes?
> 5. heapInspection.hpp line 122 - you have some funny "\" - is that intentional?
> 6. INT64_FORMAT: I think Harold just put back a change for julong handling
> that switched to using JULONG_FORMAT- see KlassInfoHisto::print_class_stats - 2 places
> (to ensure this also works on Mac OS/X)
I will double check these and fix as necessary.
> On Jan 16, 2013, at 7:39 PM, Ioi Lam wrote:
>> Please review:
>> Bug: RFE: PrintClassHistogram improvements
>> Sponsor: Karen Kinnear
>> A new diagnostic command "jcmd GC.class_stats" is added. The user
>> can invoke this command to connect to a live JVM and dump a detailed
>> report of size statistics of all loaded classes (including array
>> classes and anonymous classes).
>> $ jcmd $PID help GC.class_stats
>> Provide statistics about Java class meta data.
>> Impact: High: Depends on Java heap size and content.
>> Syntax : GC.class_stats [options] [<columns>]
>> columns : [optional] Comma-separated list of all the columns to
>> show. If not specified, the following columns are shown:
>> MethodAll,ROAll,RWAll,Total (STRING, no default value)
>> Options: (options must be specified using the <key> or <key>=<value> syntax)
>> -all : [optional] Show all columns (BOOLEAN, false)
>> -csv : [optional] Print in CSV (comma-separated values) format for
>> spreadsheets (BOOLEAN, false)
>> -help : [optional] Show meaning of all the columns (BOOLEAN, false)
>> By default, the output is human-readable tabulated text format. The
>> user can also select CSV format (comma-separated values) to be
>> used with spreadsheets.
>> A large number of columns are available. By default, a few "summary
>> columns" (e.g., size of Klass objects, total read-only data, etc)
>> are printed. The user can also manually select the columns.
>> Please see the attachments in the bug for sample output, as well as
>> a listing of all the columns and their meanings:
>> If this diagnostic command is not used, there should be no
>> impact to the JVM's execution, except for
>> + libjvm.so footprint increase (about 10KB larger on Linux/x64)
>> + one additional virtual method in Klass.
>> This feature is excluded when INCLUDE_SERVICES=0 (e.g.,
>> embedded builds).
>> Tests run:
>> + JPRT -- (hotspot only) to verify build-ability
>> + Manually ran "jcmd $PID help GC.class_stats" on Linux/x64
>> + I intend to add a new testcase once this is committed:
>> Add utility classes for writing better multiprocess tests in jtreg
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