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Issue of December 2006 
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Telescope 2007

Servers: multiple cores to go

Multi-core processors offer more computing horsepower without a corresponding rise in power consumption, an all important factor in a world where servers are shrinking and real estate is getting dearer. In the past CPU makers just raised the transistor count but there's a limit to how small you can make transistors while at the same time controlling power consumption. An alternative was required and that’s precisely the need that multi-core processor technology aims to satisfy. It multiplies the computing power of a CPU with existing technology. Now we can have one CPU package with multiple processor cores that behave like multiple processors, although power consumption remains the same as that of a traditional single-core processor, writes Varun Aggarwal.

With the ever-increasing demand for computing speed, satisfying Moore’s law is not enough. There are never enough CPU cycles to go around and sometimes it seems like ‘CPU hungry’ applications need nothing less than a super computer (unless you have hours to wait for the results). Nevertheless budgets, unlike demands, have not increased vertically. They remain much the same. Multiple processors have long been the answer to enterprise computing needs, but CIOs opting for this option face the wall of budget limitations.

With multi-core processors, we can now have many processor chips on a single die or even multiple dies in one socket, letting corporate users attain multi-processor capabilities for a lower cost in terms of space utilisation, power consumption and money. In this manner, using currently available architectures, computing capabilities can multiply

With multi-core processors, we can now have many processor chips on a single die or even multiple dies in one socket, letting corporate users attain multi-processor capabilities for a lower cost in terms of space utilisation, power consumption and money. In this manner, using currently available architectures, computing capabilities can multiply. With increasing computing speeds, we usually expect higher power consumption. However, with most multi-core architectures, the power consumption remains constant as additional cores add or rise minimally. The market is already flooded with multi-core processors and CPU vendors are boasting about their long-term plans for the same. “Higher computing density, better per watt per square feet efficiency, and much higher processing powers, the multi-core processor is the need of the hour,” explains Manoj Chandiramani, VP, IT, Man Financial.


Manoj
Chandiramani

To completely exploit the capabilities of a multi-core CPU, its essential to have applications that run in multiple, parallel threads. Unless one has a multi-threaded application, one cannot take advantage of this technology. A single-threaded application running on a multi-core CPU, can only utilise one core, thus the entire load comes on that single core, regardless of the number of cores that are available. The remaining cores will remain idle in such a scenario. Keeping this factor in mind, most enterprise software vendors have moved towards multi-threaded applications that can execute parallel threads, thus taking the complete advantage of a multi-core processor, although this move was sparked by the shift to multi-processor systems in the first place. That said, it fits nicely into the multi-core paradigm.

Software licencing on multi-core architectures
Software vendor
Licencing Policies
 
Per core
Per processor
Other
Microsoft  
 
Sybase
   
Novell  
 
Oracle     (Depends on the processor family/architecture)
Sun     (One licence per box, irrespective of the number of
processors or cores)
SGI
   

Looking at the potential of multi-core technology, Intel has launched three variants of multi-core processors—Core2 Extreme for desktops, and multi-core Xeon and Itanium processors for servers. The company claims a performance increase of 70 percent in the case of the Core2 Quad Extreme 6700 from the Dual-core Extreme Processor X6800. Comparing current generation Dual-core Xeon 5100 series based servers, the Quad-Core Xeon processors are supposed to offer 50 percent better performance.


Amit Sheth

Currently 85 percent of all server-CPUs manufactured by Intel are multi-core, and Intel intends to raise that to 90 percent in 2007. It also plans to move from the current 65 nm architecture (Core architecture) to 45nm (code name Nehalem) in 2008 and eventually to 32nm (code name Gesher) in 2010. With this development, Intel expects a 300 percent boost in performance per watt. With the increasing number of applications and users, Sun Pharma shifted from Pentium-based HP servers to Itanium 2. Amit Sheth, Head, IT, Sun Pharma points out, “Since the deployment of Itanium 2 in December 2005, we’ve seen a performance increase of over 200 percent.”

“The introduction of Quad-Core processor families have shown Performance and Performance / Watt benefit across the board. Virtualisation and reliability are the major vectors of differentiation,“ says Narendra Bhandari, Director, Asia-Pacific, Intel.

Manufacturer
Product Family
No. of Cores
Special Features
Intel Xeon 4 Clock Speed: 1.66GHz to 2.66GHz
FSB: 1066 MHz to 1333MHz
105 W TDP
Intel Virtualisation Technology
Fully buffered DIMM and Intel I/O acceleration
Intel Itanium 2 Clock Speed: 1.6 GHz
FSB: 400/533 MHz
Power Consumption: 104 W
Two complete 64 Bit processing cores
L3 cache: 6 MB (single-core) to 24 MB (dual-core)
AMD Opteron 2 to 4 AMD64 Technology, Direct Connect Architecture - connects the processors, integrated memory controller, and I/O directly to the CPU and communicates at CPU speed
HyperTransport technology - provides a scalable bandwidth interconnect between processors, I/O subsystems, and other chipsets, with up to three coherent HyperTransport technology links
Bandwidth: 24.0 GBps peak bandwidth per processor
Integrated Memory Controller - integrated on-die DDR2 DRAM memory controller offers available memory bandwidth up to 10.7 GBps (with DDR2-667) per processor
Sun UltraSparc IV+ 2 Clock Speed: 1.5 GHz
L2 Cache: 2 MB (on chip)
L3 Cache: 32 MB (off chip)
No. of parallel threads: one per core
Sun UltraSparc T1 8 Clock Speed: 1.0 to 1.2 GHz
No. of parallel threads: 4 per core
Power Consumption: 72 W
Public Key Encryption Support (RSA)
IBM Power 5 2 No. of parallel threads: two per core
L2 Cache : 1.875 MB shared by the 2 processor cores
First Level Instruction: 64KB
Data Cache: 32KB
L3 Cache: 36 MB

Sun’s UltraSparc T1 runs 32 threads per chip; four threads per processor core. The other multi-core processor from Sun, the UltraSparc IV+ is a dual core processor which runs one thread per core. The clock speeds for the UltraSparc T1 range from 1.0 to 1.2 GHz. Moving from UltraSparc 3 (single-core uniprocessor) to UltraSparc T1, Sun claims a performance increase of over 13 times. Meanwhile power consumption has fallen from 110W per chip in the UltraSparc 3 to 70W per chip in the UltraSparc T1. Running a SAP application results in performance gains from 400SAP to 4780SAP.

Sun’s focus for the future is on Niagara2, the chip will be based on the UltraSparc T1 platform; it plans to develop 64 threads per chip and even more threads per core. “Sun has diverted its entire focus towards multi-core architecture and all the processors going forth would be based on multi-core architecture only,” asserts Arnab Roy, General Manager, Marketing, Sun Microsystems.

SQL Server 2000 and 2005 support multi-core architectures.

The tangled web of licencing

Software licencing has always been a knotty problem. In the case of multi-core CPUs it remains a complicated topic. One thing is certain, the cost of acquiring software can come down drastically if a vendor considers a CPU as a single unit regardless of the number of cores on it. Microsoft and Novell do just that; they charge you for only one CPU regardless of the number of cores that it sports.

If your server has a single processor with four cores, you’ll require only one licence if you’re buying software from Microsoft or Novell. Whereas, in the case of a server with two dual-core processors, you will need to buy two licences.

Oracle’s licencing policies vary based upon the platform in question and involve a processor factor that must be multiplied by the number of cores to arrive at the number of licences that must be purchased. For the UltraSparc T1, the processor factor is 0.25. For AMD / Intel chips it is 0.5; for all other multi-core servers, the processor factor is 0.75; and in case it is a single-core processor, the processor factor is 1. Let’s make it simpler by taking an example.

If an AMD, IBM, Intel or Sun UltraSparc T1 multi-core server was installed and / or running Oracle software on 8 cores, the licences would be calculated in the following manner:

IBM multi-core server: Requires 6 processor licences (8 multiplied by a factor of .75 equals 6)

Intel or AMD server: Requires 4 processor licences (8 multiplied by a factor of .50 equals 4)

Sun UltraSparc T1 server: Requires 2 processor licences (8 multiplied by a factor of .25 equals 2)

Sun UltraSparc IV+ server: Requires 6 processor licences (8 multiplied by a factor of 0.75 equals 6)

Thus taking the math into account, the actual price for your Oracle product can vary up to three times depending on the multi-core platform that you intend to deploy.

Sujay Shetty, Marketing Manager Sybase explains, “For Sybase Information management solutions our multi-core pricing policy requires the customer to licence Sybase software for all physical processors, regardless of the number of processors on which the software is installed or running. A multi-core chip with N processors or processor cores is treated as N physical processors or CPUs. This means that for a single chip containing two or more processors or processor cores, all the cores that a chip contains must be licenced.” However, for Sybase iAnywhere solutions, the enterprise mobility range of solutions, the multi-core pricing policy counts processors, and not cores.

SGI counts each processor core as a separate processor for the purpose of licencing.

Novell has been supporting multi-core architectures from SUSE Linux Enterprise Server 9 onwards. With the new release of SUSE Linux Enterprise Server 10, “We take complete advantage of all the latest processor technologies such as Multi-Core, Virtualisation, and 64-Bit. Linux being multi-threaded, takes advantage of multi-cores. There is no limit to the number of cores, theoretically we can go unlimited. We have already tested on the latest multi-core processors and it works fine,” says Prakash Advani, Linux Practice Head, Indian Subcontinent, Novell.

Novell supports AMD, Intel and IBM from x86, x86-64 to Itanium and PowerPC. Novell charges a flat rate per server up to 32-CPU sockets irrespective of the platform. “We do not charge by the number of cores,” adds Advani. The company has also integrated virtualisation out of the box. With multi-cores and virtualisation, customers can run multiple copies of the operating system on the same server and pay for a single copy. Novell does not charge extra for guest operating systems.

Sun Solaris has been supporting multi-core architectures from version 9 onwards. Solaris 10 also supports the 144-core E25K system, which contains 72 UltraSparc IV+ processors. “Solaris licencing is based on machines, not on CPUs. Sun does not charge for Solaris based on the number of cores. In fact, Solaris 10 is free and downloadable from the Internet. Solaris licences for Sun Systems come bundled at no additional charge,” informs Roy of Sun Microsystems.

 
     
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