White Paper on Turbo Boost Using Low Power Processor

Products Update for Turbo Boost with Low Power Processor Introduction
1. Introduction
1.1 Purpose of this document
The target audience of this document is Intel
®
server board and system products users who
enable Intel
®
Turbo Boost Technology and use low power Intel
®
Xeon
®
processor
3400/5500/5600 series.
This document describes Turbo Boost operations and the reason why some low power
processors’ operating core frequency may drop out of max Turbo Boost frequency when the
system processor core loading is near 100% on Intel
®
server board.
1.2 Intel
®
Turbo Boost Technology Overview
Intel
®
Turbo Boost Technology opportunistically, and automatically, allows the processor to run
faster than the marked frequency if the part is operating below power, temperature and current
limits. Intel
®
Turbo Boost technology can be engaged with any number of cores or logical
processors enabled and active. This results in increased performance of both multi-threaded
and single-threaded workloads.
BIOS contains a set-up option to enable or disable Intel
®
Turbo Boost Technology and it
operates under operating system (OS) control by engaging when the OS requests the highest
performance state (P0). Power Management settings within the OS can be adjusted to optimize
these setting. For ACPI aware operating systems, no changes are required to support Intel
®
Turbo Boost technology. The maximum frequency is dependent on the number of active cores
and varies based on the specific configuration on a per processor number basis. The amount of
time the processor spends in the Intel
®
Turbo Boost technology state will depend on workload
and operating environment.
Intel BIOS setup also contains a Turbo Boost Power Optimization setting. For Intel
®
Xeon
®
Processor 5600 Series processors with Intel
®
Turbo Boost Technology, there is a Power
Optimization feature which can be engaged to further improve power/watt performance. Intel’s
studies show that by delaying engaging Turbo Boost until the P0-state has been continually
requested for approximately 2 seconds, the overall average system performance per watt can
be increased.
When enabled, Turbo Boost Power Optimization induces this optimal 2 seconds delay in
activation of Turbo Boost. When disabled, or on processors where it is not supported, Turbo
Boost will take effect immediately in P0 state.
Intel
®
Turbo Boost Technology is available only on supported processor versions. With Intel
®
Turbo Boost technology, the processor is capable of maximizing core frequency while ensuring
that it does not exceed its electrical and thermal specifications. This means workloads that are
naturally lower in power or lightly threaded may take advantage of headroom in the form of
increased core frequency. Continual measurements of temperature, current draw, and power
consumption are used to dynamically assess headroom.
Intel
®
Turbo Boost Technology core frequency upside availability performance is constrained by
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