JDK-6214543 : CMS: more helpful message for concurrent mode failures
  • Type: Enhancement
  • Status: Resolved
  • Resolution: Fixed
  • Component: hotspot
  • Sub-Component: gc
  • Priority: P4
  • Affected Version: 1.4.2_02,1.4.2_04,1.4.2_07
  • OS: generic,solaris_8
  • CPU: generic,sparc
  • Submit Date: 2005-01-06
  • Updated Date: 2010-12-08
  • Resolved Date: 2005-06-10
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Other JDK 6
1.4.2_10Resolved 6 betaResolved
Noticed that there are no "CMS-concurrent-sweep" statements after that [03/Jan/2005:15:56:57]. 

[03/Jan/2005:14:20:32] WARNING (24945): CORE3283: stderr: 252263.030: [CMS-concurrent-sweep-start]
[03/Jan/2005:14:20:36] WARNING (24945): CORE3283: stderr: 252267.261: [CMS-concurrent-sweep: 4.177/4.231 secs]
[03/Jan/2005:14:20:36] WARNING (24945): CORE3283: stderr: 252267.262: [CMS-concurrent-reset-start]
[03/Jan/2005:14:20:36] WARNING (24945): CORE3283: stderr: 252267.422: [CMS-concurrent-reset: 0.160/0.160 secs]
[03/Jan/2005:15:24:03] WARNING (24945): CORE3283: stderr: 256075.228: [GC [1 CMS-initial-mark: 705420K(1036288K)] 705421K(1048512K), 0.0136227 secs]
[03/Jan/2005:15:24:03] WARNING (24945): CORE3283: stderr: 256075.242: [CMS-concurrent-mark-start]
[03/Jan/2005:15:24:07] WARNING (24945): CORE3283: stderr: 256078.572: [CMS-concurrent-mark: 3.330/3.330 secs]
[03/Jan/2005:15:24:07] WARNING (24945): CORE3283: stderr: 256078.573: [CMS-concurrent-preclean-start]^M
[03/Jan/2005:15:24:07] WARNING (24945): CORE3283: stderr: 256078.596: [CMS-concurrent-preclean: 0.023/0.023 secs]
[03/Jan/2005:15:24:07] WARNING (24945): CORE3283: stderr: 256078.599: [GC256078.599: [Rescan (parallel) , 0.0553983 secs]256078.654: [weak refs processing, 0.0211087 secs] [1 CMS-remark: 705420K(1036288K)] 711280K(1048512K), 0.0776254 secs]
[03/Jan/2005:15:24:07] WARNING (24945): CORE3283: stderr: 256078.677: [CMS-concurrent-sweep-start]
[03/Jan/2005:15:24:11] WARNING (24945): CORE3283: stderr: 256082.672: [CMS-concurrent-sweep: 3.899/3.995 secs]
[03/Jan/2005:15:24:11] WARNING (24945): CORE3283: stderr: 256082.672: [CMS-concurrent-reset-start]
[03/Jan/2005:15:24:11] WARNING (24945): CORE3283: stderr: 256082.815: [CMS-concurrent-reset: 0.143/0.143 secs]
[03/Jan/2005:15:56:57] WARNING (24945): CORE3283: stderr: 258049.153: [GC [1 CMS-initial-mark: 713636K(1036288K)] 713844K(1048512K), 0.0097374 secs]
[03/Jan/2005:15:56:57] WARNING (24945): CORE3283: stderr: 258049.163: [CMS-concurrent-mark-start]
[03/Jan/2005:15:57:03] WARNING (24945): CORE3283: stderr: : 1068K->0K(12224K), 0.1910539 secs]258052.944: [CMS258054.610: [CMS-concurrent-mark: 3.493/5.447 secs]
[03/Jan/2005:15:57:22] WARNING (24945): CORE3283: stderr: 258073.595: [GC [1 CMS-initial-mark: 733171K(1036288K)] 733491K(1048512K), 0.0085612 secs]
[03/Jan/2005:15:57:22] WARNING (24945): CORE3283: stderr: 258073.604: [CMS-concurrent-mark-start]
[03/Jan/2005:15:57:39] WARNING (24945): CORE3283: stderr: : 6865K->0K(12224K), 0.9945913 secs]258090.758: [CMS258091.096: [CMS-concurrent-mark: 3.559/17.492 secs]
[03/Jan/2005:15:57:58] WARNING (24945): CORE3283: stderr: 258110.178: [GC [1 CMS-initial-mark: 768101K(1036288K)] 768549K(1048512K), 0.0091307 secs]
[03/Jan/2005:15:57:58] WARNING (24945): CORE3283: stderr: 258110.187: [CMS-concurrent-mark-start]
[03/Jan/2005:15:58:16] WARNING (24945): CORE3283: stderr: 258127.313: [GC 258127.313: [ParNew: 11954K->11954K(12224K), 0.0000652 secs]258127.313: [CMS258128.415: [CMS-concurrent-mark: 3.557/18.228 secs]
[03/Jan/2005:15:58:33] WARNING (24945): CORE3283: stderr: 258145.334: [GC [1 CMS-initial-mark: 717506K(1036288K)] 718066K(1048512K), 0.0118304 secs]
[03/Jan/2005:15:58:33] WARNING (24945): CORE3283: stderr: 258145.346: [CMS-concurrent-mark-start]
[03/Jan/2005:15:58:55] WARNING (24945): CORE3283: stderr: : 6532K->0K(12224K), 1.8597741 secs]258165.643: [CMS258166.575: [CMS-concurrent-mark: 3.562/21.228 secs]
[03/Jan/2005:15:59:13] WARNING (24945): CORE3283: stderr: 258184.975: [GC [1 CMS-initial-mark: 770501K(1036288K)] 770741K(1048512K), 0.0096138 secs]
[03/Jan/2005:15:59:13] WARNING (24945): CORE3283: stderr: 258184.985: [CMS-concurrent-mark-start]
[03/Jan/2005:15:59:32] WARNING (24945): CORE3283: stderr: : 11947K->0K(12224K), 2.3358861 secs]258202.439: [CMS258203.892: [CMS-concurrent-mark: 3.506/18.907 secs]
[03/Jan/2005:15:59:48] WARNING (24945): CORE3283: stderr: 258219.937: [GC [1 CMS-initial-mark: 716085K(1036288K)] 716470K(1048512K), 0.0076492 secs]
[03/Jan/2005:15:59:48] WARNING (24945): CORE3283: stderr: 258219.945: [CMS-concurrent-mark-start]
[03/Jan/2005:16:00:14] WARNING (24945): CORE3283: stderr: : 5185K->0K(12224K), 2.4303478 secs]258244.898: [CMS258246.097: [CMS-concurrent-mark: 3.515/26.152 secs]
[03/Jan/2005:16:00:36] WARNING (24945): CORE3283: stderr: 258267.877: [GC [1 CMS-initial-mark: 868463K(1036288K)] 868719K(1048512K), 0.0083395 secs]
[03/Jan/2005:16:00:36] WARNING (24945): CORE3283: stderr: 258267.886: [CMS-concurrent-mark-start]
[03/Jan/2005:16:00:53] WARNING (24945): CORE3283: stderr: : 11605K->0K(12224K), 2.5810415 secs]258283.306: [CMS258285.568: [CMS-concurrent-mark: 3.445/17.682 secs]
[03/Jan/2005:16:01:12] WARNING (24945): CORE3283: stderr: 258304.297: [GC [1 CMS-initial-mark: 782716K(1036288K)] 783165K(1048512K), 0.0086518 secs]
[03/Jan/2005:16:01:12] WARNING (24945): CORE3283: stderr: 258304.306: [CMS-concurrent-mark-start]
[03/Jan/2005:16:01:29] WARNING (24945): CORE3283: stderr: : 1683K->0K(12224K), 2.4806704 secs]258319.408: [CMS258321.570: [CMS-concurrent-mark: 3.420/17.264 secs]
[03/Jan/2005:16:01:50] WARNING (24945): CORE3283: stderr: 258341.680: [GC [1 CMS-initial-mark: 813600K(1036288K)] 813856K(1048512K), 0.0125876 secs]
[03/Jan/2005:16:01:50] WARNING (24945): CORE3283: stderr: 258341.693: [CMS-concurrent-mark-start]

###@###.### 2005-1-06 03:25:59 GMT

I am changing this bug's synopsis from:
CMS-concurrent-sweep messages missing from a "normal" concurrent CMS cycle
CMS: concurrent mode failures running S1AS at NCS installation
to track the main nature of the current investigation.
The secondary issue of explicating the verbose gc messages
regarding occurance of a concurrent mode failure will also
be tackled as part of this investigation, but is not the
main thrust of thos bug.
###@###.### 2005-1-12 23:25:10 GMT

I am changing this bug's synopsis (yet again),
based on the current status of this engagement, from:

CMS: concurrent mode failures running S1AS at NCS installation


CMS: more helpful message for concurrent mode failures
###@###.### 2005-03-04 21:14:58 GMT

SUGGESTED FIX Event: putback-to Parent workspace: /net/jano.sfbay/export/disk05/hotspot/ws/main/gc_baseline (jano.sfbay:/export/disk05/hotspot/ws/main/gc_baseline) Child workspace: /net/prt-web.sfbay/prt-workspaces/20050310092810.ysr.bugs/workspace (prt-web:/net/prt-web.sfbay/prt-workspaces/20050310092810.ysr.bugs/workspace) User: ysr Comment: --------------------------------------------------------- Original workspace: neeraja:/net/spot/scratch/ysr/bugs Submitter: ysr Archived data: /net/prt-archiver.sfbay/data/archived_workspaces/main/gc_baseline/2005/20050310092810.ysr.bugs/ Webrev: http://analemma.sfbay.sun.com/net/prt-archiver.sfbay/data/archived_workspaces/main/gc_baseline/2005/20050310092810.ysr.bugs/workspace/webrevs/webrev-2005.03.10/index.html Fixed 6214543: CMS: more helpful message for concurrent mode failure http://analemma.sfbay/net/spot/scratch/ysr/bugs/webrev [If you happen to look at the bug report, this started out as an investigation of conc mode failures at a customer site in Singapore, but that issue was resolved as the customer had overlooked switching on class unloading with CMS. The customer-facing engineer however wanted the concurrent mode failure messages to be more explicit. A fortnight ago, a similar request came in from Nortel, which is the second SR in this CR.] We declare "(concurrent mode failure)" whenever an ongoing CMS collection is interrupted by an explicit GC request or, irrespective of an ongoing CMS cycle, the VM needed to bail into a stop-world collection of the CMS heap. For the case where we collect because of explicit user request but do not interrupt an ongoing concurrent cycle, we do not print a message declaring concurrent mode failure. The final form of the code gained from a simplification suggested by Jon. Reviewed by: Paul Hohensee, Jon Masamitsu Fix verified: yes Verification testing: run with CMS and artificially small heap to induce frequent concurrent mode failures; note that explicit requests do not print the message unless they collide with an ongoing concurrent collection. Also tested with -XX:+ExplicitGCInvokesConcurrent and with CMSInitiatingOccupancyFraction=100 UseCMSInitiatingOccupancyOnly Files: update: src/share/vm/memory/concurrentMarkSweepGeneration.cpp Examined files: 3217 Contents Summary: 1 update 3216 no action (unchanged) ###@###.### 2005-03-10 23:30:48 GMT

EVALUATION The most recent update from the customer-facing engineer appears to indicate that the problem was a pilot error because of not enabling class unloading with CMS (where it is off by default). Since we have not received any further updates on this issue, we will (unless informed otherwise) use this bug to affect update of the verbose gc messages to explicate the occurance of a concurrent mode failure. Those changes will be in 1.6.0 and will be available on an as-needed basis to back port to older releases as an EOU issue. ###@###.### 2005-03-01 17:34:07 GMT Explicated in the verbose gc logs, the occurance of a concurrent mode failure; look for "concurrent mode failure". See suggested fix field. The fix is simple and may be backported to 1.4.2 at the discretion of JPSE. ###@###.### 2005-03-10 23:30:48 GMT This has long been integrated into Mustang. Why hasn't this been marked "Integrated" yet? Check with ###@###.###; this sounds like a process snafu. ###@###.### 2005-05-27 23:07:48 GMT I am marking this integrated since I have not heard back from Erik about this. ###@###.### 2005-06-10 18:05:55 GMT

WORK AROUND In verbose gc logs +PrintGCDetails look for a pattern that matches: [GC: [ParNew: x^*][CMS x^*] x^*] where x is any character other than "[" or "]". The above match indicates a concurrent mode failure. ###@###.### 2005-03-04 21:14:59 GMT