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Java Forum / General / March 2006Dual Core Opteron and Java threads
I'm Considering a new workstation with 2 dual core opterons running FC4. I'm wondering if anybody has had any experience with an architecture like this, and had any comments on any known issues? Specifically regarding Java threads, how the VM treats each core in terms of SMP (recognizing the entire system as 2- way processing or 4-way processing?), memory issues, etc? Thanks in advance, Andy Andy sez: > I'm Considering a new workstation with 2 dual core opterons running > FC4. I'm wondering if anybody has had any experience with an > architecture like this, and had any comments on any known issues? > Specifically regarding Java threads, how the VM treats each core in > terms of SMP (recognizing the entire system as 2- way processing or > 4-way processing?), memory issues, etc? Don't have any dual-cores, but until 2.6.15 our 2 single core opterons were dropping tcp connections at random. That's on two fairly lightly loaded webservers and one development machine. So the first thing you'll want to do is install 2.6.15 kernel from updates. Didn't notice anything special about Java apps -- except of course FC4 comes with (unusable) gcj that everything else depends on and with Debian's alternatives system from hell. Thankfully, jpackage does a good job at rolling Sun's 1.5 tarball into rpms that install properly (as in don't conflict with gcj and update /etc/alternatives correctly). Dima  SignaturePolitics and religion are just like software and hardware. They all suck, the documentation is provably incorrect, and all the vendors tell lies. -- Andrew Dalgleish > Don't have any dual-cores, but until 2.6.15 our 2 single core opterons > were dropping tcp connections at random. That's on two fairly lightly > loaded webservers and one development machine. Interesting. But do you /really/ use FC4 on a production machine? (I use FC4 on my main development machine, but even if that machine has uptime in months [yup, months] I wouldn't use FC4 for a production system) > Didn't notice anything special about Java apps -- except of course > FC4 comes with (unusable) gcj that everything else depends on and > with Debian's alternatives system from hell. Thankfully, jpackage > does a good job at rolling Sun's 1.5 tarball into rpms that install > properly (as in don't conflict with gcj and update /etc/alternatives > correctly). rpm means needing to be root to install the package (one major drawback of the rpm packaging system). I prefer a tarball that can be installed in userland over an rpm that mandates root. It's also way easier to play/test/swap/upgrade when needing to work with different virtual machines (1.4, 1.5, beta 1.6, IBM, etc.). That said, YMMV. :) lewmania942@yahoo.fr sez: >> Don't have any dual-cores, but until 2.6.15 our 2 single core opterons >> were dropping tcp connections at random. That's on two fairly lightly >> loaded webservers and one development machine. > > Interesting. But do you /really/ use FC4 on a production machine? Not much choice: we have to run a binary-only app on the backend, and the only x86 binary available is Linux. I'm getting the authors to build a x86 Solaris version, in the meantime, Linux it is. AMDs are not that well supported by 2.4 kernels, so it should to be a 2.6-based distro. We've been using dead rat since 6.2 and I haven't seen anything that would objectively prove FC worse (or better) than any other 2.6-based distro. > (I use FC4 on my main development machine, but even if that > machine has uptime in months [yup, months] I wouldn't use > FC4 for a production system) dmaziuk@yellowtail:~% uname -a Linux yellowtail.bmrb.wisc.edu 2.6.11-1.27_FC3 #1 Tue May 17 \ 20:27:37 EDT 2005 i686 i686 i386 GNU/Linux dmaziuk@yellowtail:~% uptime 18:38:48 up 207 days, 2:03, 9 users, load average: 0.00, 0.02, 0.07 ;) (I'd bump it to 4, but then I'd lose the uptime.) Seriously, though, the problem is SMP, AMD, or both. Linux has been stable enough for production use on single Intel chips for years. Dima SignatureThe speed at which a mistyped command executes is directly proportional to the amount of damage done. -- Joe Zeff Hi, I am about to make a Linux Dual Core system. Did anyone of you tested with SuSE OSS or with the more server-like CentOS distribution? > lewmania942@yahoo.fr sez: >>> Don't have any dual-cores, but until 2.6.15 our 2 single core opterons [quoted text clipped - 10 lines] > seen anything that would objectively prove FC worse (or better) > than any other 2.6-based distro. How many distros did you tried? It is really important to know this detail. And apart from the tcp drops did you tried any up-date to patch. I have not seen any coments on that on the net. I am starting to became concerned abou it ... >> (I use FC4 on my main development machine, but even if that >> machine has uptime in months [yup, months] I wouldn't use [quoted text clipped - 10 lines] > Seriously, though, the problem is SMP, AMD, or both. Linux has been > stable enough for production use on single Intel chips for years. If you notice the Open source only version in Suse Linux site: http://www.novell.com/coolsolutions/tip/16015.html One can compare with the"full" version: http://www.novell.com/products/linuxpackages/professional/index.html and see that some packages for smp are not present. I am not sure if the x86_64 is really equivalent as the i586 packages mentioned on the page. But if it is the OSS version lacks the following packages that can make the diference ... kernel-bigsmp-nongpl-2.6.13-15.i586.rpm kernel-default-nongpl-2.6.1 3-15.i586.rpm kernel-smp-nongpl-2.6.13-15.i586.rpm kernel-um-nongpl-2 .6.13-15.i586.rpm kernel-xen-nongpl-2.6.13-15.i586.rpm (this one is just for xen installations) Not to mention that aparently the JVM is not 1.5 the one suposely "optimized" for 64 bit and Dual Core. It is missing: java-1_4_2-gcj-compat-1.4.2.0-9.i586.rpm java-1_4_2-g cj-compat-devel-1.4.2.0-9.i586.rpm java-1_4_2-sun-1.4.2.06-5.i586.rpm java-1_4_2-sun-alsa-1.4.2.06-5.i586.rpm java-1_4_2-sun-demo-1.4.2.06-5. i586.rpm java-1_4_2-sun-devel-1.4.2.06-5.i586.rpm java-1_4_2-sun-jdbc -1.4.2.06-5.i586.rpm java-1_4_2-sun-plugin-1.4.2.06-5.i586.rpm java-1 _4_2-sun-src-1.4.2.06-5.i586.rpm java-1_5_0-sun-1.5.0_03-2.i586.rpm j ava-1_5_0-sun-alsa-1.5.0_03-2.i586.rpm java-1_5_0-sun-demo-1.5.0_03-2.i5 86.rpm java-1_5_0-sun-devel-1.5.0_03-2.i586.rpm java-1_5_0-sun-jdbc-1 .5.0_03-2.i586.rpm java-1_5_0-sun-plugin-1.5.0_03-2.i586.rpm I did not check FC but I suspect FC4 might have the same sort of problems ... Regards, Pedro ... And apart from the tcp drops did you tried any up-date to patch. I have not seen any coments on that on the net. I am starting to became concerned abou it ... ... This is somthing that I'm a little worried about too. I've heard that the Install for FC4 is not exactly an out of the box for 2 dual core opterons. Something about installing for a single processor, and then rebuilding the kernal SMP. I dont know the details, but if this is so, I'm wondering how stable the up2date patches will be. Free MagazinesGet these publications absolutely FREE for up to 12 months. There are no hidden fees and no obligation. Simply choose a title, complete the application form and submit it. Read more ...
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