Re: Ignorance about some things.
Gregor Schneider wrote: No, in fact the 64-bit-jvm is able to adress (thus use) more memory than on 32-bit-jvm. just make sure that a 64-bit-jvm (java-virtual-machine) is installed. Actually, in machine terms, pointers in a 64-bit system are twice as wide and thus take up twice as much space. Every reference is a pointer. Depending upon the machine implementation, even loops and conditionals could possibly use 64-bit pointers as well so those would use more memory if they did. So yes, a 64-bit system will always use at least somewhat more memory than a 32-bit system that does the same thing. This is not to say that there couldn't be a memory leak in the 64-bit JVM that doesn't exist in the 32-bit JVM. I'm just saying that all else being equal, the 64-bit version will use more memory -- because it has to. I remember when I was first playing with 64-bit systems in the mid 1990's (C/C++) and was surprised to find that many programs actually ran slower when recompiled for 64-bits. One of the reasons for that was because they're moving around more memory just to move their pointers around. Unless you have big memory and need big memory, or you're doing a lot of arithmetic with 64-bit integers, it's usually best to stay with the 32-bit version. It will usually be at least as fast if not faster and use less memory. Of course, if you need the big memory, or lots of 64-bit arithmetic then you need it so you go with 64-bit. As for the OP, you'll want to play around with -vmargs settings to your JVM. -Xmx is the obvious one. -XX:MaxPermSize is another less well known one that can help in many cases. PermGen space is one of those sneaky things they don't tell you about. You can set -Xmx really big and still have memory problems because not enough of it is available to PermGen. - To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: Ignorance about some things.
On Mon, Sep 1, 2008 at 1:41 PM, Manuel Trujillo [EMAIL PROTECTED] wrote: Is the java 64 bits more memory-eat than 32 bits? No, in fact the 64-bit-jvm is able to adress (thus use) more memory than on 32-bit-jvm. just make sure that a 64-bit-jvm (java-virtual-machine) is installed. Gregor -- what's puzzlin' you, is the nature of my game gpgp-fp: 79A84FA526807026795E4209D3B3FE028B3170B2 gpgp-key available @ http://pgpkeys.pca.dfn.de:11371 - To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: Ignorance about some things.
My experience is also that java likes more memory on 64-bit systems. But I can't prove or explain it. Ronald. On Mon Sep 01 13:41:18 CEST 2008 Tomcat Users List users@tomcat.apache.org wrote: Subject: Ignorance about some things. Date: Mon Sep 01 13:41:18 CEST 2008 From: Manuel Trujillo [EMAIL PROTECTED] Hi! Excuse me if this question is not correct for this list (also about my bad english...). I have two machines with tomcat 5.5. One is an Opensuse 10.3 32 bits, the other is the same *but* in 64 bits. Same hardware, same config, same... all. In the 32 bits machine we haven't any error about insuficient java memory; never, while into the 64 bits we need to make an automatic restart of tomcat every 50 minutes. Is the java 64 bits more memory-eat than 32 bits? Thank you for your help. Regards -- Manu - To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: Ignorance about some things.
On Mon, Sep 1, 2008 at 3:57 PM, Ronald Klop [EMAIL PROTECTED] wrote: My experience is also that java likes more memory on 64-bit systems. But I can't prove or explain it. You can tell Java exactly how much memory to use: Have a look at the -Xms and -XMX-parameters for the JVM (java -X will give you some information). You might also want to check out the -d64 - argument of the JVM. Cheers Gregor -- what's puzzlin' you, is the nature of my game gpgp-fp: 79A84FA526807026795E4209D3B3FE028B3170B2 gpgp-key available @ http://pgpkeys.pca.dfn.de:11371 - To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: Ignorance about some things.
On Mon, Sep 1, 2008 at 16:05, Gregor Schneider [EMAIL PROTECTED] wrote: On Mon, Sep 1, 2008 at 3:57 PM, Ronald Klop [EMAIL PROTECTED] wrote: My experience is also that java likes more memory on 64-bit systems. But I can't prove or explain it. You can tell Java exactly how much memory to use: Have a look at the -Xms and -XMX-parameters for the JVM (java -X will give you some information). You might also want to check out the -d64 - argument of the JVM. Sorry, because this is a date that I should have said before. The machine has 4 Gb RAM, and this is the java config (memory): JAVA_OPTS=-Xms500M -Xmx2560M Thank you for your answers. -- Manuel Trujillo Albarral Director de Sistemas Informáticos VLEX NETWORKS S.L. Telf: 93-272.26.85 ext. 157 GoogleTalk [EMAIL PROTECTED] http://www.vlex.com
RE: Ignorance about some things.
From: Ronald Klop [mailto:[EMAIL PROTECTED] My experience is also that java likes more memory on 64-bit systems. But I can't prove or explain it. I would expect 64-bit Java to use 64-bit object pointers, and 32-bit Java to use 32-bit object pointers. Given how often object pointers occur in typical Java programs, that's a fair bit of extra memory. If you assume that half of a typical object's state is references to other objects, then (naively) you'll use 50% more memory. Now I'll sit back and wait for Chuck to contradict me :-). - Peter - To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: Ignorance about some things.
- Original Message - From: Manuel Trujillo [EMAIL PROTECTED] To: users@tomcat.apache.org Sent: Monday, September 01, 2008 1:41 PM Subject: Ignorance about some things. Hi! Excuse me if this question is not correct for this list (also about my bad english...). I have two machines with tomcat 5.5. One is an Opensuse 10.3 32 bits, the other is the same *but* in 64 bits. Same hardware, same config, same... all. In the 32 bits machine we haven't any error about insuficient java memory; never, while into the 64 bits we need to make an automatic restart of tomcat every 50 minutes. Is the java 64 bits more memory-eat than 32 bits? Thank you for your help. Regards -- Manu Manu 64 bit JRE is a relatively new thing in Java... The memory handling is different but its swings and balances and I dont believe it should be crashing your machine every 50 mins... The guys tell me that the JRE did have a memory heap allocation bug... in pre JRE's 6... Its not tomcat apparently if you want to play with 64 bit... get the very latest JRE 6 from SUN direct. Have fun... And dont use 64 bit on client JRE's yet... thats not all right yet, like webstart wont function etc... --- HARBOR : http://www.kewlstuff.co.za/index.htm The most powerful application server on earth. The only real POJO Application Server. See it in Action : http://www.kewlstuff.co.za/cd_tut_swf/whatisejb1.htm --- - To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: Ignorance about some things.
On Mon, Sep 1, 2008 at 7:38 PM, Johnny Kewl [EMAIL PROTECTED] wrote: The guys tell me that the JRE did have a memory heap allocation bug... in pre JRE's 6... Its not tomcat apparently if you want to play with 64 bit... get the very latest JRE 6 from SUN direct. Have fun... And dont use 64 bit on client JRE's yet... thats not all right yet, like webstart wont function etc... Johnny, you got any sources on that? We're running all 64bit-Sun-JVMs (JDK 1.5) on Debian (Lenny) Linux and we're all fine om the server-side (Tomcat and our own server-apps). We don't have any experience with 64bit-clientside, though... Cheers Gregor -- what's puzzlin' you, is the nature of my game gpgp-fp: 79A84FA526807026795E4209D3B3FE028B3170B2 gpgp-key available @ http://pgpkeys.pca.dfn.de:11371 - To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: Ignorance about some things.
- Original Message - From: Gregor Schneider [EMAIL PROTECTED] To: Tomcat Users List users@tomcat.apache.org Sent: Monday, September 01, 2008 9:04 PM Subject: Re: Ignorance about some things. On Mon, Sep 1, 2008 at 7:38 PM, Johnny Kewl [EMAIL PROTECTED] wrote: The guys tell me that the JRE did have a memory heap allocation bug... in pre JRE's 6... Its not tomcat apparently if you want to play with 64 bit... get the very latest JRE 6 from SUN direct. Have fun... And dont use 64 bit on client JRE's yet... thats not all right yet, like webstart wont function etc... Johnny, you got any sources on that? We're running all 64bit-Sun-JVMs (JDK 1.5) on Debian (Lenny) Linux and we're all fine om the server-side (Tomcat and our own server-apps). We don't have any experience with 64bit-clientside, though... Cheers Linux admin guys just knocked off... I'll ask them to explain the details in the morning... They just said something about a major/minor heap allocation problem on earlier JREs You know these debian dudes... talk a language from another planet ;) --- HARBOR : http://www.kewlstuff.co.za/index.htm The most powerful application server on earth. The only real POJO Application Server. See it in Action : http://www.kewlstuff.co.za/cd_tut_swf/whatisejb1.htm --- - To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: Ignorance about some things.
Hello Manuell, having OutOfMemoryError in your logs doesnt necessary mean that you are out of memory. OutOfMemory error can be caused by many things, for example the impossiblity to create a new thread. What's happening with your tomcat after 50 minutes, do you have any logs? Also, detailed info about your hardware and software setup would be helpful regads Leon On Mon, Sep 1, 2008 at 2:41 PM, Manuel Trujillo [EMAIL PROTECTED] wrote: Hi! Excuse me if this question is not correct for this list (also about my bad english...). I have two machines with tomcat 5.5. One is an Opensuse 10.3 32 bits, the other is the same *but* in 64 bits. Same hardware, same config, same... all. In the 32 bits machine we haven't any error about insuficient java memory; never, while into the 64 bits we need to make an automatic restart of tomcat every 50 minutes. Is the java 64 bits more memory-eat than 32 bits? Thank you for your help. Regards -- Manu - To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] - To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: Ignorance about some things.
Hi Johnny, On Mon, Sep 1, 2008 at 9:26 PM, Johnny Kewl [EMAIL PROTECTED] wrote: Linux admin guys just knocked off... I'll ask them to explain the details in the morning... They just said something about a major/minor heap allocation problem on earlier JREs You know these debian dudes... talk a language from another planet ;) well, I'm a Debian-dude myself, and that's why I'm keen to know about those issues. If you can manage to talk to them again, send me the transcript, I'm gonna translate it for you ;) Cheers Gregor -- what's puzzlin' you, is the nature of my game gpgp-fp: 79A84FA526807026795E4209D3B3FE028B3170B2 gpgp-key available @ http://pgpkeys.pca.dfn.de:11371 - To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
