zhang yu. a few years ago (like centuries in electronic world) frequency was considered the key...
TRANSCRIPT
Zhang Yu
A few years ago (like centuries in electronic world) frequency was considered the key element of a cpu`s performance, because of Intel`s dominance in the market place and their continuous bragging about frequency.
In November 2000 Intel's heavily advertised advances in clock speed reached an extreme with the release of the Pentium 4 which sacrificed per-cycle performance and used a deep instruction pipeline to gain higher clock speeds, ignoring problems that this introduced of heat production and power consumption.
Intel: “I am the fastest!” AMD, Apple etc. : “No you are not!”
They decided to settle this…. Let`s race!
Bunny is fast indeed but unfortunately prone to make mistakes….
Deep instruction pipeline (e.g. if a prediction is wrong
performance penalty will be greater because of deeper pipeline.)
higher clock speeds introduced heat production and power consumption
As computer architecture advanced, it became more difficult to compare the performance of various computer systems simply by looking at their specifications. Therefore, tests were developed that allowed comparison of different architectures
Benchmarks are particularly important in CPU design, giving processor architects the ability to measure and make tradeoffs in microarchitectural decisions
Benchmarks are designed to mimic a particular type of workload on a component or system
Industry Standard (audited and verifiable) Business Applications Performance
Corporation (BAPCo) Embedded Microprocessor Benchmark
Consortium (EEMBC) Standard Performance Evaluation
Corporation (SPEC) Transaction Processing Performance
Council (TPC)
BAPCo: MobileMark, SYSmark, WebMark Futuremark:3DMark, PCMark Whetstone PiFast Super PI WinSAT, exclusively for Windows Vista,
providing an index for consumers to rate their systems easily
Benchmarking is not easy and often involves several iterative rounds in order to arrive at predictable, useful conclusions.
Vendors tend to tune their products specifically for industry-standard benchmarks
Benchmarks do not address questions which you did not ask… only see what you measure
Specific application benchmarks will not tell you
about the performance of other applications without proper analysis => extrapolation is not straightforward
You must understand the benchmark itself to understand what it tells you
General benchmarks will not tell you about the details of your specific application
When more power is used, a portable system will have a shorter battery life and require recharging more often. This is often the antithesis of performance as most semiconductors require more power to switch faster
nVidia`s Geforce graphic card: The cooling fan on this card is so
powerful that it can be used to clean the door way.
In 2004 problems of overheating led Intel to abandon further development of its Netburst microarchitecture
The newest version of SPEC (SPECpower_ssj2008) counts power consumption as one of the key factor in performance.
overall ssj_ops/Watt Nowadays we often use Gflops/Watt as
an indicator of performance
http://en.wikipedia.org/wiki/Computer_benchmark
http://www.spec.org/power_ssj2008/ http://en.wikipedia.org/wiki/
Megahertz_myth http://en.wikipedia.org/wiki/
Performance_per_watt