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Apparatus for Limiting the Sustained Processor Throughput

IP.com Disclosure Number: IPCOM000245163D
Publication Date: 2016-Feb-16
Document File: 2 page(s) / 34K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a novel u-throttle system and method for limiting the sustained processor throughput. The u-throttle is a targeted method for delaying instructions in the issue window before sending the instructions to the execution units and allowing bursts of unlimited throughput for a specified number of cycles.

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Apparatus for Limiting the Sustained Processor Throughput

The drive for performance increase in recent and future microprocessor cores leads to a significant increase in the peak power dissipated by the microprocessors. The maximum power is typically achieved when executing a highly optimized program code specifically developed to create such high-power scenarios. Such programs are typically referred to as power viruses. The power viruses are written to achieve a close to 100% utilization of the microprocessor resources by using hand-optimized code employing contrived techniques to cause maximum throughput conditions, whereas the programs performing useful computations typically can utilize only a fraction of the processor resources on a sustained bases. Consequently, with the increasing peak throughput in the microprocessor cores, the gap in power between the viruses and useful programs has been rapidly increasing.

Power management, also referred to as dynamic voltage-frequency scaling (DVFS) is a prior art technique used to limit the maximum power, temperature, or current in the microprocessor chips. These techniques collect the measurements of power/current/temperature collected from on-chip or off-chip sensors and respond to the increase in power/temperature/current by lowering the frequency and power supply of the microprocessor. This causes the operating frequency of the processor to depend on the environment such as ambient temperature, fan speed, humidity, and/or altitude. Moreover, the frequency varies from chip to chip and even from core to core. The DVFS works well for customers who can accept the non-deterministic frequency behavior; however, a large set of customers require deterministic frequency.

For example, under thermal management, the job completes by 7:00 a.m. most of the time. The customer deconfigures the system or increases workload to make it 8:00 a.m., and everyone is satisfied until summer comes. Then, on hot days, the temperature increase triggers DVFS and the frequency is reduced. As a result, the customer's over-night jobs are completed by 10:00 a.m., missing the deadline. The customer checks the frequency and finds out that the processor is running at 3.3GHz instead of 3.5GHz, for which the customer paid.

The novel u-throttle techniques make both frequency and performance independent of the environment as well...