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The moose likes Performance and the fly likes   tomcat 3.3.1 takes a high time for Minor GC using JDK 1.4.2 build 28  Big Moose Saloon
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tomcat 3.3.1 takes a high time for Minor GC using JDK 1.4.2 build 28

Akash Jauhar
Greenhorn

Joined: Mar 03, 2004
Posts: 1
Hi All
Our application runs on the following platform
solaris 9
Apache 1.3.27
JDK 1.4.2 build 28
tomcat 3.3.1a
We are noticing some weird GC behaviour when the tomcat does Minor GC. I am pasting some logs below
231867.984: [GC 231867.985: [DefNew: 127232K->3840K(127232K), 0.1125831 secs] 288818K->170206K(350384K), 0.1128485 secs]
231946.970: [GC 231946.970: [DefNew: 127232K->3840K(127232K), 0.1348222 secs] 293598K->177196K(350384K), 0.1350464 secs]
231968.052: [GC 231968.052: [DefNew: 127232K->3840K(127232K), 0.1818662 secs] 300588K->182066K(350384K), 0.1821628 secs]
231969.314: [GC 231969.315: [DefNew: 127232K->3543K(127232K), 16.4172505 secs] 305458K->185389K(350384K), 16.4175191 secs]
231987.248: [GC 231987.248: [DefNew: 126935K->3840K(127232K), 10.7419554 secs] 308781K->189356K(350384K), 10.7422411 secs]
231999.225: [GC 231999.225: [DefNew: 127232K->3840K(127232K), 16.1320322 secs] 312748K->196413K(350384K), 16.1323798 secs]
232015.949: [GC 232015.950: [DefNew: 127232K->3840K(127232K), 42.2998381 secs] 319805K->201339K(350384K), 42.3001041 secs]
232058.781: [GC 232058.781: [DefNew: 127232K->3840K(127232K), 146.5896470 secs] 324731K->206361K(350384K), 146.5898922 secs]
232206.831: [GC 232206.832: [DefNew: 127232K->3840K(127232K), 110.7859999 secs] 329753K->211019K(350384K), 110.7862726 secs]
232318.209: [GC 232318.209: [DefNew: 127232K->3840K(127232K), 68.5541489 secs] 334411K->215994K(350384K), 68.5544029 secs]
232387.893: [GC 232387.893: [DefNew: 127232K->3840K(127232K), 126.8755081 secs] 339386K->221793K(350384K), 126.8757738 secs]
232515.276: [GC 232515.276: [DefNew: 127232K->3840K(127232K), 139.7813258 secs]232655.058: [Tenured: 223686K->154822K(223792K), 278.7132327 secs] 345201K->154822K(351024K), 418.4964431 secs]
232934.349: [GC 232934.349: [DefNew: 123392K->3840K(127232K), 164.3069723 secs] 278214K->163782K(385272K), 164.3072616 secs]
233099.848: [GC 233099.848: [DefNew: 127232K->3840K(127232K), 91.4000872 secs] 287174K->169894K(385272K), 91.4005897 secs]
233191.652: [GC 233191.652: [DefNew: 127232K->3840K(127232K), 204.1755072 secs] 293286K->176929K(385272K), 204.1757747 secs]
233396.272: [GC 233396.272: [DefNew: 127232K->3840K(127232K), 101.8621946 secs] 300321K->183426K(385272K), 101.8624498 secs]

Note how the minor collection takes high GC times. it takes as high as 204 seconds. We are using the default GC also both for the old generation and the young generation. Our heap sizee when the tomcat starts is bounded by 256 MB on the lower side to 778 MB on the higher side.
I am unable to understand what would cause tomcat to do GC for such a long time esp in the young generation. what is even more wierd is that the time between consecutive GC for young generation is almost equal to time for which the GC happened . what would cause the young generation to fill so quickly.
Anyone has any ideas what is going on ?
-Akash
 
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subject: tomcat 3.3.1 takes a high time for Minor GC using JDK 1.4.2 build 28
 
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