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IBM Linux Centre - p615 wins 5 Penguins
home ) linux ) p615 wins 5 penguins
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In November 2003, Linus Torvalds said:
The reason Alpha died wasn't technology. Alpha died because you can't afford to push an architecture that doesn't have wide appeal. This is why AMD64 and the POWER architectures are interesting, and why Itanium eventually will die unless Intel starts seriously changing their approach to it. AMD64 and POWER - in Opteron and the 970 respectively - both have 64-bit architectures with a very real, wide appeal.
Opteron and the AMD64 platform have certainly gotten a lot of coverage over the last year as the 64-bit mass market Linux platform of choice. But what of POWER, the IBM platform of which the Chief Penguin spoke so highly? Linux Magazine thought this merited a closer look and decided to take the System-p5 (pseries) 615, IBM's first entry-level 64-bit POWER4 server, for a two-week spin.
The System-p5 (pseries) 615 is not the first IBM POWER architecture series machine able to run Linux, but it has the distinction of being first in the sub-$10,000 category to do so. Like the current nerd status symbol, the Power Mac G5, the p615 also sports a PowerPC-derived 64-bit RISC processor manufactured by IBM Microelectronics that eats floating point calculations for lunch. However this is where the similarities between the two machines end. To use a car analogy, it's like comparing a Chevy Camaro to GM's NASCAR racer: both cars share some heritage, and the NASCAR machine may even be called a Camaro on the race track by the sports announcers, but the racing vehicle has evolved into an almost completely different animal.
The POWER4 chip in the p615, running at 1.4 Ghz, is actually a Dual-Core chip, meaning that it contains twin processor cores, or SMP on a single silicon wafer. Additionally, these twin cores share a massive 8 MB L3 cache (by comparison, the G5 in the Power Mac only has a 512K cache). This big cache makes the POWER4 ideal for database intensive tasks. Anyone want to run an Oracle or DB2 RDBMS a few million rows long, or perhaps you want to sequence a genome or two? Coupled with the super-fast Ultra320 IBM SCSI disk RAID controller and Ultra320 drives that are sold with the unit, as well as the 16 GB (maximum) system memory and special proprietary high-speed IBM bus architecture, it makes for one very serious high-performance Linux server - one that could eat your average Sun box for lunch, and at a very competitive price.
But specs and pricing alone don't make a great server. What about the software? The p615 can run RedHat Enterprise Server 3.0, as well as the lastest SUSE SLES 8 64-bit Linux OS, and both install just as easily as their Intel cousins. Linux Magazine had a chance to play with both of these, and had over twenty developers accessing our evaluation machine 24 hours a day over a two-week period, and most were quite happy with the tools provided in these 64-bit POWER distros and were able to port their code fairly quickly to the architecture.
For example, the leader of the GMP project (http://www.swox.com/gmp)
was able to port their precision mathematics library in a
day or two with the compilers and tools that came with RHEL
3. IBM also provides an optimizing version of their VisualAge
C++ compiler, for those who want to run their software pretty
close to the metal. If you've got a good in-house developer
crew, you'd be hard pressed to find a better high-performance
Linux server than the p615.
But what about third-party tools and pre-compiled applications? Arguably, this is where we start getting into community-related issues and has little to do with any fault or shortcomings in the hardware. We couldn't find any such shortcomings in the machine itself. If anything, the p615 is a shining example of IBM's superior hardware engineering and support.
Currently, much of the focus on PowerPC Linux development lies within the Macintosh Linux user community scattered among a number of sites all over the Net. As of yet, there is no central resource for finding 64-bit apps that run on POWER. To complicate matters, a lot of pre-existing, pre-compiled 32-bit and 64-bit RPMs written for PowerPC won't run on Red Hat Enterprise Linux 3 due to glibc versioning issues. We had to fall back to SLES 8.0 for many of these to work. As glibc is the core of the Linux ABI, it makes for some sticky and frustrating issues, especially if the source code to the application is not available to do a quick recompile. We encountered this for example with the 64-bit version of SETI, which we wanted to use to benchmark the p615's number crunching capabilities. We had to fall back to a 32-bit version because the 64-bit version was written for an older glibc.
Bottom Line: Buy
Overall we were very happy with the performance, reliability and the user experience surrounding our use of the p615. Our issues with the platform are mostly centered on the state of the developer community for Linux on POWER. As of this writing, with the rollout of the p615 and other new POWER architecture Linux machines (such as the ultra-sexy IBM JS20 Bladecenter that will be demonstrated at LinuxWorld Expo in NYC), IBM has started to compile and make available applications on its DeveloperWorks site, such as the 64-bit IBM Java Virtual Machine and the IBM DB2 relational database. POWER ports of enterprise applications from Tier-1 vendors such as Oracle are forthcoming.
We hope that IBM continues to really push this architecture and to foster better relations between IBM and software developers to better enable them to create some very compelling and exploitive applications for this really great high performance, scalable platform.
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