(The goal of this blog post is not really to educate you on how to tune Java on UltraSPARC-T1 (Niagara) platform, but to warn you not to completely rely on the out-of-the-box features of Solaris 10 and Java, with couple of interesting examples).Scenario:Customer XYZ heard very good things about UltraSPARC-T1 (Niagara) based coolthreads servers; and the out of the box performance of Solaris 10 Update 1 and Java SE 5.0. So, he bought an US-T1 based T2000 server; and deployed his application on this server running the latest update of Solaris 10 with...
Tuesday, 21 November 2006
Sunday, 19 November 2006
Solaris: Workaround for incorrect LUN size issue
Posted on 22:40 by Unknown
Scenario:You created a logical drive of capacity x GB, and mapped it so there is a LUN (Logical Unit Number) with size x GB. When you run format command, Solaris shows incorrect size for the logical drive.eg.,Partition table showing only 409 GB, where it is supposed to show 816 GB.partition> pCurrent partition table (original):Total disk cylinders available: 53233 + 2 (reserved cylinders)Part Tag Flag Cylinders Size Blocks 0 root wm 0 - 16 133.88MB (17/0/0) 274193 1 swap...
Thursday, 16 November 2006
Solaris: Disabling Out Of The Box (OOB) Large Page Support
Posted on 01:21 by Unknown
Starting with the release of Solaris 10 1/06 (aka Solaris 10 Update 1), large page OOB feature turns on MPSS (Multiple Page Size Support) automatically for applications' data (heap) and text (libraries).One obvious advantage of this large page OOB feature is that it improves the performance of user land applications by reducing the wastage of CPU cycles in serving iTLB and dTLB misses. For example, if the heap size of a process is 256M, on a Niagara (UltraSPARC-T1) box it will be mapped on to a single 256M page. On a system that doesn't support...
Monday, 13 November 2006
Sun: OpenJDK
Posted on 00:27 by Unknown
Open source JDK, that is. Sun Microsystems did it again -- As promised during JavaOne event back in May 2006, Sun made the implementation of the Java Platform, Standard Edition, available to the community under GNU General Public License (GPLv2).Note that only HotSpot Virtual Machine and javac (compiler) components of the earlier builds of JDK version 7 are open sourced as of now. Rest of the components will be open sourced over the time; and by the end of first half of 2007, we will have fully buildable implementation for JDK 7.OpenJDK web site...
Friday, 10 November 2006
Oracle: Explain plan & Tracing a particular SQL
Posted on 23:52 by Unknown
Scenario:You are on a mission to fix majority of database related performance issues in production environment - so, you are actively taking snapshots of the database during peak hours and generating AWR reports for the performance data.Now you have the list of long running SQLs under SQL ordered by Elapsed Time section of the report. One of the next steps is to trace such SQLs to see what is happening when they get executed. Since we can extract the SQL identifier (SQL Id) from the AWR report for all top SQLs, tracing can be enabled as shown below....
Wednesday, 8 November 2006
Oracle: Snapshots and AWR report
Posted on 00:32 by Unknown
Starting with Oracle 10g database management system, Oracle offers a set of scripts to extract performance statistics from Automatic Workload Repository (AWR) to generate a human readable report. This report will be a starting point in finding {and fixing them sometimes, almost with no additional effort} the bottlenecks in the database system.Oracle automatically generates snapshots of the performance data once every hour and stores the statistics in the workload repository. While diagnosing some issues, it might be necessary to take several snapshots...
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