每日彙整: 2018-09-25

樹莓派、樹莓派之學習、樹莓派之教育

樹莓派 3B+ 筦窺︰ GigaBit ︰ 300MBit ！Benchmarks ☆

論語‧子路

子夏為莒父宰，問政。子曰：無欲速，無見小利。欲速，則不達；見小利，則大事不成。

閱讀往往需要循序漸進、由淺入深，貪快者常常欲速則不達。一路所言彷彿長而不當，不過祇是墊腳石而已。方便學習者能進出天下文章，無入而不可自得也。

─── 《光的世界︰【□○閱讀】折射式望遠鏡《六》》

 

樹莓派 3B+ 追求『基準』標竿︰

Roy Longbottom at Linkedin Roy Longbottom’s Raspberry Pi, Pi 2 and Pi 3 Benchmarks

 

New

I have now run my 32 bit and 64 bit Raspberry Pi benchmarks and stress tests on the model 3B+. Full details and results are available from ResearchGate in the Raspberry Pi 3B+ PDF Report. The tests demonstrate 3B+/3B performance improvements (not always), the new thermal characteristics and higher speed LAN and WiFi data transfers.

Contents

General Raspberry Pi System 64 Bit SUSE & Gentoo
Standards/Configuration Details Whetstone Benchmark Dhrystone 2 Benchmark
Linpack Benchmark Livermore Loops Benchmark Memory Speed Benchmark
Bus Speed Benchmark FFT Benchmarks  
     
NEON Benchmarks Linpack NEON Benchmarks NEON Float & Integer Benchmark
NEON MemSpeed Benchmark Maximum 1 Core MFLOPS  
     
MultiThreading Benchmarks MP-MFLOPS MP-Whetstone
MP-Dhrystone MP-BusSpeed MP-RandMem
OpenMP-MFLOPS OpenMP-MemSpeed  
NEON MP Benchmarks MP-NeonMFLOPS linpackNeonMP
     
Java Benchmarks Java Whetstone Benchmarks JavaDraw Benchmark
OpenGL ES Benchmark OpenGL GLUT Benchmark  
     
DriveSpeed Benchmark LAN/WiFi Benchmark 64 Bit Drive & LAN Benchmarks
Temperature & MHz Recorder Reliability Tests 64 Bit Reliability Tests
Performance Monitor Assembly Code

 

能有什麼不對嗎？

事實上，數據顯示它表現的還不錯哩！

Benchmarking the Raspberry Pi 3 B+

Gareth Halfacree

The launch of the shiny new Raspberry Pi 3 B+ offers a chance to revisit the entire history of the Pi family, benchmarking each device in turn from the original Raspberry Pi Model B launch board with its somewhat limited 256MB of RAM right through to the shiniest and newest board. This post collates the results from a range of different benchmarks, demonstrating how the power of the Pi has changed over the years.

If attempting to replicate the results yourself, there is one key fact to note: the Raspberry Pi has enjoyed somewhere in the range of a 30 percent performance uplift in the last couple of years through software and firmware optimisation alone; comparing the same benchmark run on a Pi using the latest Raspbian operating system today with results gathered a year or more ago will give a false reading, which is why all these results have been gathered using the same firmware and software revision.

Update: The benchmarks in this article have been updated after it was discovered that the Pi Zero on test had developed a fault. The Pi Zero benchmarks have been re-run on a new board and updated, while the Pi Zero W’s SysBench score has also been updated to reflect improvements brought about by the latest firmware release. The figures in this article are now accurate and up-to-date as per the version of Raspbian released on the 14th of March 2018.

 

或許因為某些『效能參數』調的過高！統計『樣本數目』採樣太少 ？以至於有時候扛不動『背包』呦︰

250px-Knapsack.svg

背包問題

假使有 n 種物品，物品 k 的重量是 w_k，價格為 p_k。如果我們有個背包，最大能載重 W，要是各種物品只能選或者不選，那麼『最高價』的裝法是什麼？數學上來講，就是在『滿足』
\qquad \sum_{k=1}^n w_k\,x_k \ \leqslant \ W, \quad \quad x_k \ \in \ \{0,1\}  的『條件』下，求
\qquad \sum_{k=1}^n p_k\,x_k 之『最大化』的問題。

一般來說這類的『問題』相當普遍，舉例來說︰

背包 → 時段

物品 → 活動

物品重量 → 活動長短

物品價格 → 活動價值

，那它就被『翻譯』成『一日、一年』之計之『規劃』的了！！

由於人們通常關心效能『基測』 benchmark ing 的『結果』，因此在《 Benchmarking Raspberry Pi 2 》一文中，樹莓派基金會也從善如流，論及『比較結果』。然因目前樹莓派 2B 雖然已是 ARMV7 ，可以跑很多其它不同的 Linux 發行版，卻持守著『 V7/V6 』之『相容性』，所以有人議論

Raspberry Pi 2: Linaro(ARMv7) vs Raspbian(ARMv6) Benchmarks!

的高下！

─── 摘自《7︰6》

 

對比著『速度』，系統『穩定性』更加重要吧☆

sudo MEMTESTER_TEST_MASK=0x1000 memtester 128M

memtester(8)                 Maintenance Commands                 memtester(8)

NAME
       memtester - stress test to find memory subsystem faults.

SYNOPSIS
       memtester [-p PHYSADDR [-d DEVICE]] <MEMORY> [ITERATIONS]

DESCRIPTION
       memtester  is an effective userspace tester for stress-testing the mem‐
       ory subsystem.  It is very effective at finding intermittent  and  non-
       deterministic  faults.   Note  that  problems  in  other hardware areas
       (overheating CPU, out-of-specification power supply,  etc.)  can  cause
       intermittent memory faults, so it is still up to you to determine where
       the fault lies through normal hardware diagnostic procedures; memtester
       just helps you determine whether a problem exists.

       memtester  will  malloc(3) the amount of memory specified, if possible.
       If this fails, it will decrease the amount of memory requested until it
       succeeds.   It  will then attempt to mlock(3) this memory; if it cannot
       do so, testing will be slower and much less effective.   Run  memtester
       as root so that it can mlock the memory it tests.