RE: problem in GC tuning

[Prashant kumar]

I require that much of memory to avoid GC.
Is there any other way out for it ?



-Original Message-
From: Michael Echerer [mailto:[EMAIL PROTECTED] 
Sent: Friday, May 26, 2006 8:14 PM
To: Tomcat Users List
Subject: Re: problem in GC tuning

Prashant kumar wrote:
 Hi All,

  
  1)  Is there any means  by which GC takes less CPU,  I mean that it
 can take longer time to complete  its one cycle (as memory is not a
 constraint) ? 

You've set quite a lot of heap 3400m. Do you really need that much
memory? The more you set, the more the GC needs to scan. If it's unused
however, try reducing Xmx and Xms to values that are sufficient for your
app.
Then try to size the generations to get smaller chunks to be scanned and
check the survivor ratios.

Give the incremental GC a try. Might get worse, but probably it works.

http://java.sun.com/docs/hotspot/gc1.4.2
  
 2)  Do writing of logs at higher loads have some impact on the
 performance?
  
You should definitely disable GC logging in production, if you don't
need it for diagnosis anylonger.

Cheers,
Michael



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problem in GC tuning

[Prashant kumar]

]
7974.834: [GC 7974.835: [ParNew: 198272K-0K(198464K), 0.1811506 secs]
1040910K-855650K(3481408K) icms_dc=10 , 0.1813716 secs]
7981.902: [GC 7981.902: [ParNew: 198272K-0K(198464K), 0.2050517 secs]
1053922K-870454K(3481408K) icms_dc=10 , 0.2052528 secs]
7991.449: [GC 7991.449: [ParNew: 198272K-0K(198464K), 0.1999756 secs]
1068726K-885800K(3481408K) icms_dc=10 , 0.2002290 secs]
8001.095: [GC 8001.095: [ParNew: 198272K-0K(198464K), 0.1956788 secs]
1084072K-901229K(3481408K) icms_dc=10 , 0.1958831 secs]
8005.477: [CMS-concurrent-preclean: 3.660/36.604 secs]
8005.478: [GC8005.879: [weak refs processing, 0.0033165 secs] [1
CMS-remark: 901229K(3282944K)] 1010055K(3481408K), 0.4045541 secs]
8005.883: [CMS-concurrent-sweep-start]
8008.666: [GC 8008.666: [ParNew: 198272K-0K(198464K), 0.1572205 secs]
1099394K-913209K(3481408K) icms_dc=10 , 0.1574554 secs]
8018.200: [GC 8018.200: [ParNew: 198272K-0K(198464K), 0.1762875 secs]
1029950K-846961K(3481408K) icms_dc=10 , 0.1764872 secs]
8027.796: [GC 8027.796: [ParNew: 198272K-0K(198464K), 0.1764513 secs]
1018796K-835879K(3481408K) icms_dc=10 , 0.1766460 secs]
8036.182: [GC 8036.183: [ParNew: 198272K-0K(198464K), 0.1496021 secs]
1005163K-819861K(3481408K) icms_dc=10 , 0.1498642 secs]
8045.035: [GC 8045.035: [ParNew: 198272K-0K(198464K), 0.1714910 secs]
969596K-786671K(3481408K) icms_dc=10 , 0.1716964 secs]
8049.630: [CMS-concurrent-sweep: 4.484/43.747 secs]
8049.630: [CMS-concurrent-reset-start]
8049.974: [CMS-concurrent-reset: 0.344/0.344 secs]
8054.626: [GC 8054.626: [ParNew: 198272K-0K(198464K), 0.1614032 secs]
920368K-737444K(3481408K) icms_dc=10 , 0.1616091 secs]
8058.849: [GC [1 CMS-initial-mark: 737444K(3282944K)] 828209K(3481408K),
0.3487117 secs]
 
 
Thanks and Regards
Prashant Kumar