IBM P5 570 manual Simultaneous multi-threading, Dynamic power management, Enhanced SMT features

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2.1.1 Simultaneous multi-threading

As a permanent requirement for performance improvements at the application level, simultaneous multi-threading (SMT) functionality is embedded in the POWER5 chip technology. Developers are familiar with process-level parallelism (multi-tasking) and thread-level parallelism (multi-threads). SMT is the next stage of processor saturation for throughput-oriented applications to introduce the method of instruction group-level parallelism to support multiple pipelines to the processor. The instruction groups are chosen from different hardware threads belonging to a single OS image.

SMT is activated by default when an OS that supports it is loaded. On a 2-way POWER5 processor based system, the operating system discovers the available processors as a 4-way system. To achieve a higher performance level, SMT is also applicable in Micro-Partitioning, capped or uncapped, and dedicated partition environments (2.9, “Virtualization” on page 38).

Simultaneous multi-threading is supported on POWER5 processor-based systems running AIX 5L V5.3 or Linux-based systems at a required 2.6 kernel. AIX provides the smtctl command that turns SMT on and off without subsequent reboot. For Linux, an additional boot option must be set to activate SMT after a reboot.

The SMT mode maximizes the usage of the execution units. In the POWER5 chip, more rename registers have been introduced (for Floating Point operation, rename registers are increased to 120), that are essential for out-of-order execution and vital for the SMT.

Enhanced SMT features

To improve SMT performance for various workload mixes and provide robust quality of service, POWER5 provides two features:

￿Dynamic resource balancing

–The objective of dynamic resource balancing is to ensure that the two threads executing on the same processor flow smoothly through the system.

–Depending on the situation, the POWER5 processor resource balancing logic has a different thread throttling mechanism.

￿Adjustable thread priority

–Adjustable thread priority lets software determine when one thread should have a greater (or lesser) share of execution resources.

–The POWER5 supports eight software-controlled priority levels for each thread.

ST operation

Not all applications benefit from SMT. Having threads executing on the same processor does not increase the performance of applications with execution unit limited performance or applications that consume all of the chip’s memory bandwidth. For this reason, the POWER5 processor supports the ST execution mode. In this mode, the POWER5 processor gives all of the physical resources to the active thread, enabling it to achieve higher performance than a POWER4 processor-based system at equivalent frequencies. Highly optimized scientific codes are one example where ST operation is ideal.

2.1.2 Dynamic power management

In current CMOS1 technologies, chip power is one of the most important design parameters. With the introduction of SMT, more instructions execute per cycle per processor core, thus increasing the core’s and the chip’s total switching power. To reduce switching power,

1complementary metal oxide semiconductor

Chapter 2. Architecture and technical overview 21

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Contents IBM Eserver p5 Technical Overview Introduction Page IBM Sserver p5 570 Technical Overview Introduction First Edition July Contents Page Page Vi p5-570 Technical Overview and Introduction Vii Trademarks Team that wrote this Redpaper PrefaceComments welcome Become a published authorGeneral description P5-570 Technical Overview and Introduction Physical package System specificationsView from the front Minimum and optional featuresProcessor card FC Description Processor card featuresDisk and media features Memory featuresUSB diskette drive 5 I/O drawersModel D10 I/O drawer Model D10 I/O drawer physical package Model D20 I/O drawer Model D11 I/O drawerModel D20 I/O drawer physical package Drawers and usable PCI slotsHardware Management Console models Value PaksSystem racks Model type conversionIBM RS/6000 7014 Model T00 Enterprise Rack AC Power Distribution Unit and rack content IBM RS/6000 7014 Model T42 Enterprise RackRack-mounting rules for p5-570 and I/O drawers Flat panel display options Additional options for rackOEM rack Hardware Management Console 7310 Model CR2IBM 7212 Model 102 TotalStorage Storage device enclosure Statement of direction 18 p5-570 Technical Overview and Introduction Architecture and technical overview POWER4 POWER5 POWER5 chipEnhanced SMT features Dynamic power managementSimultaneous multi-threading ST operationPOWER4 Power chip evolutionCMOS, copper, and SOI technology Processor cardsProcessor card with DDR1 memory socket layout view Processor drawer interconnect cablesPmcycles -m Processor clock rateMemory placement rules Memory subsystemMemory restriction System buses Memory throughputRIO-2 buses and GX+ card Internal I/O subsystem SP busPCI-X slots and adapters Graphic accelerators LAN adaptersScsi adapters Bit and 32-bit adaptersInternal hot swappable Scsi disks Internal storageInternal RAID options Internal media devicesHot-swap disks and Linux External I/O subsystems 1 I/O drawers2 7311 Model D10 and 7311 Model D11 I/O drawers Model D10 features Model D11 features3 7311 Model D20 I/O drawer Model D20 internal Scsi cabling 4 7311 I/O drawer and RIO-2 cablingCost Optimized Performance Optimized 5 7311 I/O drawer and Spcn cablingIBM 2104 Expandable Storage Plus External disk subsystemsIBM 7133 Serial Disk Subsystem SSA IBM TotalStorage FAStT Storage serversIBM TotalStorage Enterprise Storage Server Dynamic logical partitioning Advanced Power Virtualization featureVirtualization Virtual EthernetMicro-Partitioning technology 15shows the POWER5 partitioning conceptVirtual I/O Server POWER5 PartitioningPartition Load Manager Service processorService processor extender Service processor baseIPL flow without an HMC attached to the system Boot processIPL flow with an HMC attached to the system Hardware Management ConsoleDefinitions of partitions Managed systemsProfiles System Management Services Hardware requirements for partitioningSpecific partition definitions used for Micro-Partitioning 17 System Management Services main menu Boot optionsDVD-ROM, DVD-RAM Additional boot optionsOperating system requirements SecurityAIX 5L Linux support LinuxCapacity on Demand, RAS, and manageability Way 1.65 GHz POWER5 processor card Processor Capacity Upgrade on Demand methodsWay 1.9 GHz POWER5 processor card with DDR1 memory slots Way 1.9 GHz POWER5 processor card with DDR2 memory slotsCapacity Upgrade on Demand for memory Capacity Upgrade on Demand for memory feature codes How to report temporary activation resourcesReliability, availability, and serviceability Fault avoidanceTrial Capacity on Demand First Failure Data Capture Permanent monitoringMutual surveillance Memory reliability, fault tolerance, and integrity Self-healingEnvironmental monitoring 5 N+1 redundancy Fault maskingResource deallocation Dynamic or persistent deallocationError indication and LED indicators ServiceabilityConcurrent Maintenance ManageabilityAdvanced System Management Interface Advanced System Management main menu Service AgentService Update Management Assistant Service focal point3 p5 Customer-Managed Microcode Cluster CSM V1.4 on AIX and Linux planned 4Q04 CSM value pointsOther publications IBM RedbooksOnline resources Help from IBM How to get IBM Redbooks68 p5-570 Technical Overview and Introduction Page IBM Eserver p5 Technical Overview Introduction

P5 570 specifications

The IBM P5 570 is a high-performance server that was designed for enterprise-scale computing, offering a blend of advanced technologies and a flexible architecture. Launched as part of IBM's Power5 server line, the P5 570 stands out for its robust processing capabilities and extensive scalability, making it a preferred choice for businesses requiring reliable and efficient computing solutions.

At the heart of the P5 570 is the IBM Power5 processor, which employs simultaneous multi-threading (SMT) technology. This allows the processor to handle two threads per core, effectively doubling the throughput for workloads ideally suited to multi-threading. The server typically features a configuration of up to 32 Power5 processors, providing an impressive compute power that supports demanding applications, ranging from databases to complex enterprise resource planning (ERP) systems.

The P5 570 architecture supports a wide range of memory configurations, with a maximum memory capacity of up to 512 GB. Utilizing IBM’s proprietary Chip Memory technology, it can deliver high bandwidth and low latency, significantly enhancing performance for memory-intensive applications. Furthermore, the integrated memory controller architecture optimizes memory access, ensuring that critical workloads run smoothly.

Scalability is a key characteristic of the P5 570, with the ability to expand processing power and memory capacity as an organization’s needs grow. The server supports various operating systems, including AIX, Linux, and IBM i, which provides flexibility for diverse IT environments. This versatility ensures that companies can run their preferred applications without the need for substantial system overhauls.

In terms of storage, the P5 570 utilizes advanced RAID technology and supports a variety of disk configurations, ensuring that data integrity and availability are maintained. Coupled with built-in security features, such as the IBM Trusted Foundation, which establishes a secure boot environment, the P5 570 offers a reliable platform for mission-critical workloads.

Finally, the IBM P5 570 is designed for high availability and redundancy. Features like hot-swappable components and advanced error detection and recovery mechanisms minimize downtime, making it a dependable choice for businesses that operate around the clock. Combined with its powerful hardware and versatile software support, the IBM P5 570 remains a formidable player in the high-performance server arena.
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