LLVM Clang 3.4 Compiler Optimization Levels Benchmarking LLVM/Clang compiler optimization levels for a future article on phoronix.com. -O3: Processor: Intel Core i7 720Q @ 1.60GHz (8 Cores), Motherboard: LENOVO 4318CTO, Chipset: Intel Core DMI, Memory: 4096MB, Disk: 160GB INTEL SSDSA2M160, Graphics: NVIDIA Quadro FX 880M 1024MB (405/324MHz), Audio: Conexant CX20585, Network: Intel 82577LM Gigabit Connection + Intel Centrino Ultimate-N 6300 OS: Ubuntu 13.10, Kernel: 3.11.0-031100rc2-generic (x86_64), Desktop: Xfce 4.10, Display Server: X Server 1.14.2, Display Driver: nouveau 1.0.8, OpenGL: 3.0 Mesa 9.1.4 Gallium 0.4, Compiler: Clang 3.4 (SVN 187338) + LLVM 3.4svn, File-System: ext4, Screen Resolution: 1600x900 -O2: Processor: Intel Core i7 720Q @ 1.60GHz (8 Cores), Motherboard: LENOVO 4318CTO, Chipset: Intel Core DMI, Memory: 4096MB, Disk: 160GB INTEL SSDSA2M160, Graphics: NVIDIA Quadro FX 880M 1024MB (405/324MHz), Audio: Conexant CX20585, Network: Intel 82577LM Gigabit Connection + Intel Centrino Ultimate-N 6300 OS: Ubuntu 13.10, Kernel: 3.11.0-031100rc2-generic (x86_64), Desktop: Xfce 4.10, Display Server: X Server 1.14.2, Display Driver: nouveau 1.0.8, OpenGL: 3.0 Mesa 9.1.4 Gallium 0.4, Compiler: Clang 3.4 (SVN 187338) + LLVM 3.4svn, File-System: ext4, Screen Resolution: 1600x900 -O1: Processor: Intel Core i7 720Q @ 1.60GHz (8 Cores), Motherboard: LENOVO 4318CTO, Chipset: Intel Core DMI, Memory: 4096MB, Disk: 160GB INTEL SSDSA2M160, Graphics: NVIDIA Quadro FX 880M 1024MB (405/324MHz), Audio: Conexant CX20585, Network: Intel 82577LM Gigabit Connection + Intel Centrino Ultimate-N 6300 OS: Ubuntu 13.10, Kernel: 3.11.0-031100rc2-generic (x86_64), Desktop: Xfce 4.10, Display Server: X Server 1.14.2, Display Driver: nouveau 1.0.8, OpenGL: 3.0 Mesa 9.1.4 Gallium 0.4, Compiler: Clang 3.4 (SVN 187338) + LLVM 3.4svn, File-System: ext4, Screen Resolution: 1600x900 -O0: Processor: Intel Core i7 720Q @ 1.60GHz (8 Cores), Motherboard: LENOVO 4318CTO, Chipset: Intel Core DMI, Memory: 4096MB, Disk: 160GB INTEL SSDSA2M160, Graphics: NVIDIA Quadro FX 880M 1024MB (405/324MHz), Audio: Conexant CX20585, Network: Intel 82577LM Gigabit Connection + Intel Centrino Ultimate-N 6300 OS: Ubuntu 13.10, Kernel: 3.11.0-031100rc2-generic (x86_64), Desktop: Xfce 4.10, Display Server: X Server 1.14.2, Display Driver: nouveau 1.0.8, OpenGL: 3.0 Mesa 9.1.4 Gallium 0.4, Compiler: Clang 3.4 (SVN 187338) + LLVM 3.4svn, File-System: ext4, Screen Resolution: 1600x900 -Os: Processor: Intel Core i7 720Q @ 1.60GHz (8 Cores), Motherboard: LENOVO 4318CTO, Chipset: Intel Core DMI, Memory: 4096MB, Disk: 160GB INTEL SSDSA2M160, Graphics: NVIDIA Quadro FX 880M 1024MB (405/324MHz), Audio: Conexant CX20585, Network: Intel 82577LM Gigabit Connection + Intel Centrino Ultimate-N 6300 OS: Ubuntu 13.10, Kernel: 3.11.0-031100rc2-generic (x86_64), Desktop: Xfce 4.10, Display Server: X Server 1.14.2, Display Driver: nouveau 1.0.8, OpenGL: 3.0 Mesa 9.1.4 Gallium 0.4, Compiler: Clang 3.4 (SVN 187338) + LLVM 3.4svn, File-System: ext4, Screen Resolution: 1600x900 -Ofast: Processor: Intel Core i7 720Q @ 1.60GHz (8 Cores), Motherboard: LENOVO 4318CTO, Chipset: Intel Core DMI, Memory: 4096MB, Disk: 160GB INTEL SSDSA2M160, Graphics: NVIDIA Quadro FX 880M 1024MB (405/324MHz), Audio: Conexant CX20585, Network: Intel 82577LM Gigabit Connection + Intel Centrino Ultimate-N 6300 OS: Ubuntu 13.10, Kernel: 3.11.0-031100rc2-generic (x86_64), Desktop: Xfce 4.10, Display Server: X Server 1.14.2, Display Driver: nouveau 1.0.8, OpenGL: 3.0 Mesa 9.1.4 Gallium 0.4, Compiler: Clang 3.4 (SVN 187338) + LLVM 3.4svn, File-System: ext4, Screen Resolution: 1600x900 SciMark 2.0 Computational Test: Fast Fourier Transform Mflops > Higher Is Better -O3 .... 173.57 |========================================================= -O2 .... 189.72 |============================================================== -O1 .... 189.10 |============================================================== -O0 .... 189.30 |============================================================== -Os .... 190.14 |============================================================== -Ofast . 188.06 |============================================================= FLAC Audio Encoding 1.3.0 WAV To FLAC Seconds < Lower Is Better -O3 .... 8.86 |============= -O2 .... 9.00 |============= -O1 .... 11.26 |================ -O0 .... 44.12 |=============================================================== -Os .... 11.16 |================ -Ofast . 8.85 |============= LAME MP3 Encoding 3.99.3 WAV To MP3 Seconds < Lower Is Better -O3 .... 22.64 |===================== -O2 .... 22.72 |===================== -O1 .... 23.55 |====================== -O0 .... 67.47 |=============================================================== -Os .... 23.04 |====================== -Ofast . 22.00 |===================== Timed HMMer Search 2.3.2 Pfam Database Search Seconds < Lower Is Better -O3 .... 27.33 |=================== -O2 .... 27.31 |=================== -O1 .... 30.89 |====================== -O0 .... 89.33 |=============================================================== -Os .... 28.68 |==================== -Ofast . 27.10 |=================== Himeno Benchmark 3.0 Poisson Pressure Solver MFLOPS > Higher Is Better -O3 .... 1055.08 |========================================================= -O2 .... 1129.56 |============================================================= -O1 .... 1105.36 |============================================================ -O0 .... 127.95 |======= -Os .... 1102.68 |============================================================ -Ofast . 1128.50 |============================================================= N-Queens 1.0 Elapsed Time Seconds < Lower Is Better -O3 .... 345.38 |=================== -O2 .... 343.18 |=================== -O1 .... 386.21 |====================== -O0 .... 1083.88 |============================================================= -Os .... 331.72 |=================== -Ofast . 343.65 |=================== Timed ImageMagick Compilation 6.8.1-10 Time To Compile Seconds < Lower Is Better -O3 .... 65.88 |============================================================== -O2 .... 65.30 |============================================================== -O1 .... 57.37 |====================================================== -O0 .... 23.14 |====================== -Os .... 63.33 |============================================================ -Ofast . 66.55 |=============================================================== Timed PHP Compilation 5.2.9 Time To Compile Seconds < Lower Is Better -O3 .... 41.97 |=============================================================== -O2 .... 35.51 |===================================================== -O1 .... 31.28 |=============================================== -O0 .... 18.55 |============================ -Os .... 33.44 |================================================== -Ofast . 42.15 |=============================================================== GraphicsMagick 1.3.16 Operation: Blur Iterations Per Minute > Higher Is Better -O3 .... 53 |================================================================== -O2 .... 53 |================================================================== -O1 .... 53 |================================================================== -O0 .... 22 |=========================== -Os .... 52 |================================================================= -Ofast . 53 |================================================================== GraphicsMagick 1.3.16 Operation: Sharpen Iterations Per Minute > Higher Is Better -O3 .... 36 |================================================================== -O2 .... 36 |================================================================== -O1 .... 35 |================================================================ -O0 .... 10 |================== -Os .... 36 |================================================================== -Ofast . 36 |================================================================== GraphicsMagick 1.3.16 Operation: Resizing Iterations Per Minute > Higher Is Better -O3 .... 66 |================================================================= -O2 .... 66 |================================================================= -O1 .... 66 |================================================================= -O0 .... 24 |======================== -Os .... 66 |================================================================= -Ofast . 67 |================================================================== GraphicsMagick 1.3.16 Operation: HWB Color Space Iterations Per Minute > Higher Is Better -O3 .... 80 |====================================================== -O2 .... 80 |====================================================== -O1 .... 81 |======================================================= -O0 .... 36 |======================== -Os .... 79 |====================================================== -Ofast . 97 |================================================================== GraphicsMagick 1.3.16 Operation: Local Adaptive Thresholding Iterations Per Minute > Higher Is Better -O3 .... 32 |================================================================== -O2 .... 32 |================================================================== -O1 .... 31 |================================================================ -O0 .... 8 |================= -Os .... 30 |============================================================== -Ofast . 31 |================================================================ C-Ray 1.1 Total Time Seconds < Lower Is Better -O3 .... 75.98 |======================= -O2 .... 103.77 |=============================== -O1 .... 100.11 |============================== -O0 .... 208.53 |============================================================== -Os .... 104.72 |=============================== -Ofast . 93.63 |============================ Smallpt 1.0 Global Illumination Renderer; 100 Samples Seconds < Lower Is Better -O3 .... 293 |========================= -O2 .... 292 |========================= -O1 .... 410 |=================================== -O0 .... 770 |================================================================= -Os .... 320 |=========================== -Ofast . 275 |=======================