ARM GCC 4.7.2 Cortex-A15 Compiler Optimizations
Benchmarking compiler optimization levels on GCC 4.7.2 from a Google Nexus 10 with Samsung Exynos 5 Dual SoC. It's an ARM Cortex-A15 dual-core 1.7GHz processor. Benchmarking by Michael Larabel for a future article on Phoronix.


-Os: 

	Processor: ARMv7 rev 4 @ 1.70GHz (2 Cores), Motherboard: Manta, Memory: 2048MB, Disk: 16GB MAG2GA

	OS: Ubuntu 12.10, Kernel: 3.4.5-gf68518f (armv7l), Compiler: GCC 4.7, File-System: ext4, Screen Resolution: 2560x1600

-O0: 

	Processor: ARMv7 rev 4 @ 1.70GHz (2 Cores), Motherboard: Manta, Memory: 2048MB, Disk: 16GB MAG2GA

	OS: Ubuntu 12.10, Kernel: 3.4.5-gf68518f (armv7l), Compiler: GCC 4.7, File-System: ext4, Screen Resolution: 2560x1600

-O1: 

	Processor: ARMv7 rev 4 @ 1.70GHz (2 Cores), Motherboard: Manta, Memory: 2048MB, Disk: 16GB MAG2GA

	OS: Ubuntu 12.10, Kernel: 3.4.5-gf68518f (armv7l), Compiler: GCC 4.7, File-System: ext4, Screen Resolution: 2560x1600

-O2: 

	Processor: ARMv7 rev 4 @ 1.70GHz (2 Cores), Motherboard: Manta, Memory: 2048MB, Disk: 16GB MAG2GA

	OS: Ubuntu 12.10, Kernel: 3.4.5-gf68518f (armv7l), Compiler: GCC 4.7, File-System: ext4, Screen Resolution: 2560x1600

-O3: 

	Processor: ARMv7 rev 4 @ 1.70GHz (2 Cores), Motherboard: Manta, Memory: 2048MB, Disk: 16GB MAG2GA

	OS: Ubuntu 12.10, Kernel: 3.4.5-gf68518f (armv7l), Compiler: GCC 4.7, File-System: ext4, Screen Resolution: 2560x1600

-Ofast: 

	Processor: ARMv7 rev 4 @ 1.70GHz (2 Cores), Motherboard: Manta, Memory: 2048MB, Disk: 16GB MAG2GA

	OS: Ubuntu 12.10, Kernel: 3.4.5-gf68518f (armv7l), Compiler: GCC 4.7, File-System: ext4, Screen Resolution: 2560x1600


C-Ray 1.1
Total Time
Seconds < Lower Is Better
-Os .... 588.38 |========================================
-O0 .... 909.85 |==============================================================
-O1 .... 653.17 |=============================================
-O2 .... 523.58 |====================================
-O3 .... 349.83 |========================
-Ofast . 332.87 |=======================


GraphicsMagick 1.3.16
Operation: Blur
Iterations Per Minute > Higher Is Better
-Os .... 29 |==============================================================
-O0 .... 16 |==================================
-O1 .... 30 |================================================================
-O2 .... 31 |==================================================================
-O3 .... 30 |================================================================
-Ofast . 31 |==================================================================


GraphicsMagick 1.3.16
Operation: Sharpen
Iterations Per Minute > Higher Is Better
-Os .... 20 |=========================================================
-O0 .... 7  |====================
-O1 .... 19 |=======================================================
-O2 .... 23 |==================================================================
-O3 .... 23 |==================================================================
-Ofast . 23 |==================================================================


GraphicsMagick 1.3.16
Operation: Resizing
Iterations Per Minute > Higher Is Better
-Os .... 36 |===========================================================
-O0 .... 16 |==========================
-O1 .... 36 |===========================================================
-O2 .... 40 |==================================================================
-O3 .... 40 |==================================================================
-Ofast . 39 |================================================================


GraphicsMagick 1.3.16
Operation: HWB Color Space
Iterations Per Minute > Higher Is Better
-Os .... 48 |==========================================================
-O0 .... 27 |================================
-O1 .... 47 |========================================================
-O2 .... 47 |========================================================
-O3 .... 47 |========================================================
-Ofast . 55 |==================================================================


GraphicsMagick 1.3.16
Operation: Local Adaptive Thresholding
Iterations Per Minute > Higher Is Better
-Os .... 19 |=========================================================
-O0 .... 6  |==================
-O1 .... 19 |=========================================================
-O2 .... 22 |==================================================================
-O3 .... 22 |==================================================================
-Ofast . 22 |==================================================================


Himeno Benchmark 3.0
Poisson Pressure Solver
MFLOPS > Higher Is Better
-Os .... 100.58 |============================================
-O0 .... 60.43  |==========================
-O1 .... 108.57 |================================================
-O2 .... 140.04 |=============================================================
-O3 .... 141.55 |==============================================================
-Ofast . 129.49 |=========================================================


Open FMM Nero2D 2.0.2
Total Time
Seconds < Lower Is Better
-Os .... 3505.78 |============================
-O0 .... 7634.24 |=============================================================
-O1 .... 2300.70 |==================
-O2 .... 2142.95 |=================
-O3 .... 2149.05 |=================
-Ofast . 2145.44 |=================


Opus Codec Encoding 1.0.1
WAV, Opus Encode, Opus Decode
Seconds < Lower Is Better
-Os .... 55.78  |=====================
-O0 .... 163.43 |==============================================================
-O1 .... 51.84  |====================
-O2 .... 47.80  |==================
-O3 .... 46.64  |==================
-Ofast . 45.73  |=================


Smallpt 1.0
Global Illumination Renderer; 100 Samples
Seconds < Lower Is Better
-Os .... 784  |====================================
-O0 .... 1388 |================================================================
-O1 .... 361  |=================
-O2 .... 329  |===============
-O3 .... 1297 |============================================================
-Ofast . 279  |=============


Timed PHP Compilation 5.2.9
Time To Compile
Seconds < Lower Is Better
-Os .... 204.10 |============================================
-O0 .... 117.17 |=========================
-O1 .... 191.56 |=========================================
-O2 .... 252.76 |=======================================================
-O3 .... 285.41 |==============================================================
-Ofast . 286.52 |==============================================================