Hi Jini,

This looks good. I'm totally fine with skipping metaspace if that isn't displayed for the other GCs.


On 2018-03-09 10:29, Jini George wrote:
Here is the revised webrev:


I have made modifications to have the 'universe' command display details like:

hsdb> universe
Heap Parameters:
garbage-first heap [0x0000000725200000, 0x00000007c0000000] region size 1024K
G1 Heap:
   regions  = 2478
   capacity = 2598371328 (2478.0MB)
   used     = 5242880 (5.0MB)
   free     = 2593128448 (2473.0MB)
   0.20177562550443906% used
G1 Young Generation:
Eden Space:
   regions  = 5
   capacity = 8388608 (8.0MB)
   used     = 5242880 (5.0MB)
   free     = 3145728 (3.0MB)
   62.5% used
Survivor Space:
   regions  = 0
   capacity = 0 (0.0MB)
   used     = 0 (0.0MB)
   free     = 0 (0.0MB)
   0.0% used
G1 Old Generation:
   regions  = 0
   capacity = 155189248 (148.0MB)
   used     = 0 (0.0MB)
   free     = 155189248 (148.0MB)
   0.0% used

I did not add the metaspace details since that did not seem to be in line with the 'universe' output for other GCs. I have added a new command "g1regiondetails" to display the region details, and have modified the tests accordingly.

hsdb> g1regiondetails
Region Details:
Region: 0x0000000725200000,0x0000000725200000,0x0000000725300000:Free
Region: 0x0000000725300000,0x0000000725300000,0x0000000725400000:Free
Region: 0x0000000725400000,0x0000000725400000,0x0000000725500000:Free
Region: 0x0000000725500000,0x0000000725500000,0x0000000725600000:Free
Region: 0x0000000725600000,0x0000000725600000,0x0000000725700000:Free
Region: 0x0000000725700000,0x0000000725700000,0x0000000725800000:Free


On 2/28/2018 12:56 PM, Jini George wrote:
Thank you very much, Stefan. My answers inline.

On 2/27/2018 3:30 PM, Stefan Johansson wrote:
Hi Jini,

JIRA ID:https://bugs.openjdk.java.net/browse/JDK-8175312
Webrev: http://cr.openjdk.java.net/~jgeorge/8175312/webrev.00/index.html

It looks like a file is missing, did you forget to add it to the changeset?

Indeed, I had missed that! I added the missing file in the following webrev:


open/src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/gc/g1/G1CollectedHeap.java:36: error: cannot find symbol
import sun.jvm.hotspot.gc.shared.PrintRegionClosure;

Otherwise the change looks good, but I would like to see the output live. For a big heap this will print a lot of data, just wondering if the universe command is the correct choice for this kind of output. I like having the possibility to print all regions, so I want the change but maybe it should be a different command and 'universe' just prints a little more than before. Something like our logging heap-summary at shutdown: garbage-first heap   total 16384K, used 3072K [0x00000000ff000000, 0x0000000100000000)
  region size 1024K, 4 young (4096K), 0 survivors (0K)
Metaspace       used 6731K, capacity 6825K, committed 7040K, reserved 1056768K   class space    used 559K, capacity 594K, committed 640K, reserved 1048576K

Ok, will add this, and could probably have the region details displayed under a new command called "g1regiondetails", or some such, and send out a new webrev.


Modifications have been made to display the regions like:

Region: 0x00000005c5400000,0x00000005c5600000,0x00000005c5600000:Old
Region: 0x00000005c5600000,0x00000005c5800000,0x00000005c5800000:Old
Region: 0x00000005c5800000,0x00000005c5a00000,0x00000005c5a00000:Old
Region: 0x00000005c5a00000,0x00000005c5c00000,0x00000005c5c00000:Old
Region: 0x00000005c5c00000,0x00000005c5c00000,0x00000005c5e00000:Free
Region: 0x00000005c5e00000,0x00000005c5e00000,0x00000005c6000000:Free
Region: 0x00000005c6000000,0x00000005c6200000,0x00000005c6200000:Old

The jtreg test at this point does not include any testing for the display of archived or pinned regions. The testing for this will be added once JDK-8174994 is resolved.

The SA tests pass with jprt and Mach5.


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