1. Computers
  2. Display Drivers
  3. Graphics Cards
  4. Memory
  5. Motherboards
  6. Processors
  7. Software
  8. Storage
  9. Operating Systems


Facebook RSS Twitter Twitter Google Plus


Phoronix Test Suite

OpenBenchmarking.org

ARM Cortex-A15 GCC Compiler Tuning Performance

Compiler

Published on 04 December 2012 09:41 AM EST
Written by Michael Larabel in Compiler
3 Comments

To complement the recent compiler benchmarking on the ARM Cortex-A15 as found in the Samsung Exynos 5 Dual with the Samsung Chromebook, here's some compiler tuning benchmark results from the speedy low-power ARM system.

Uploaded to OpenBenchmarking.org this morning are a couple compiler tests when building the various Phoronix Test Suite test profiles with different GCC compiler tuning flags. The GCC ARM compiler options are mentioned in their online documentation. The ARM options being compared in this article include the stock compiler flags (no additional CFLAGS/CXXFLAGS set) compared to:

-mtune=cortex-a15
This option is very similar to the -mcpu= option, except that instead of specifying the actual target processor type, and hence restricting which instructions can be used, it specifies that GCC should tune the performance of the code as if the target were of the type specified in this option, but still choosing the instructions it generates based on the CPU specified by a -mcpu= option. For some ARM implementations better performance can be obtained by using this option.

-marm
Select between generating code that executes in ARM and Thumb states. The default for most configurations is to generate code that executes in ARM state, but the default can be changed by configuring GCC with the --with-mode=state configure option.

-mfpu=neon
This specifies what floating-point hardware (or hardware emulation) is available on the target. Permissible names are: `vfp', `vfpv3', `vfpv3-fp16', `vfpv3-d16', `vfpv3-d16-fp16', `vfpv3xd', `vfpv3xd-fp16', `neon', `neon-fp16', `vfpv4', `vfpv4-d16', `fpv4-sp-d16', `neon-vfpv4', `fp-armv8', `neon-fp-armv8', and `crypto-neon-fp-armv8'. If the selected floating-point hardware includes the NEON extension (e.g. -mfpu=`neon'), note that floating-point operations are not generated by GCC's auto-vectorization pass unless -funsafe-math-optimizations is also specified. This is because NEON hardware does not fully implement the IEEE 754 standard for floating-point arithmetic (in particular denormal values are treated as zero), so the use of NEON instructions may lead to a loss of precision.

In 1212044-RA-CORTEX15G86 are GCC 4.6 and GCC 4.7 stock benchmarks and then GCC 4.7 when testing various compiler tuning options. However, from this Samsung Exynos 5 Dual notebook, there isn't a huge performance difference to see.

Within 1212043-RA-COMPILERT89 are additional benchmark results from trying different GCC ARMv7 options, but again, the results aren't too mind-blowing.

About The Author
Michael Larabel is the principal author of Phoronix.com and founded the web-site in 2004 with a focus on enriching the Linux hardware experience and being the largest web-site devoted to Linux hardware reviews, particularly for products relevant to Linux gamers and enthusiasts but also commonly reviewing servers/workstations and embedded Linux devices. Michael has written more than 10,000 articles covering the state of Linux hardware support, Linux performance, graphics hardware drivers, and other topics. Michael is also the lead developer of the Phoronix Test Suite, Phoromatic, and OpenBenchmarking.org automated testing software. He can be followed via and or contacted via .
Latest Linux Hardware Reviews
  1. MSI X99S SLI PLUS On Linux
  2. NVIDIA GeForce GTX 970 Offers Great Linux Performance
  3. CompuLab Intense-PC2: An Excellent, Fanless, Mini PC Powered By Intel's i7 Haswell
  4. From The Atom 330 To Haswell ULT: Intel Linux Performance Benchmarks
Latest Linux Articles
  1. RunAbove: A POWER8 Compute Cloud With Offerings Up To 176 Threads
  2. 6-Way Ubuntu 14.10 Linux Desktop Benchmarks
  3. Ubuntu 14.10 XMir System Compositor Benchmarks
  4. Btrfs RAID HDD Testing On Ubuntu Linux 14.10
Latest Linux News
  1. openSUSE Factory & Tumbleweed Are Merging
  2. More Fedora Delays: Fedora 21 Beta Slips
  3. Mono Brings C# To The Unreal Engine 4
  4. Coreboot Now Has Support For Intel Broadwell Hardware
  5. Enlightenment's EFL 1.12 Alpha Has Evas GL-DRM Engine, OpenGL ES 1.1 Support
  6. GTK+ Lands Experimental Backend For Mir Display Server
  7. Ubuntu 14.10 Officially Released
  8. Mesa 10.4 Might Re-Enable HyperZ For R600g/RadeonSI
  9. Intel GVT-g GPU Virtualization Moves Closer
  10. GTK+ 3.16 To Bring Several New Features
Latest Forum Discussions
  1. Updated and Optimized Ubuntu Free Graphics Drivers
  2. Ubuntu 16.04 Might Be The Distribution's Last 32-Bit Release
  3. Linux hacker compares Solaris kernel code:
  4. HOPE: The Ease Of Python With The Speed Of C++
  5. Advertisements On Phoronix
  6. Users/Developers Threatening Fork Of Debian GNU/Linux
  7. AMD Releases UVD Video Decode Support For R600 GPUs
  8. Proof that strlcpy is un-needed