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. Trying The Configurable 45 Watt TDP With AMD's A10-7800 / A6-7400K
  2. Sumo's Omni Gets Reloaded
  3. AMD A10-7800 & A6-7400K APUs Run Great On Linux
  4. Radeon Gallium3D Is Running Increasingly Well Against AMD's Catalyst Driver
Latest Linux Articles
  1. Open-Source Radeon Graphics Have Some Improvements On Linux 3.17
  2. CPUFreq Scaling Tests With AMD's Kaveri On Linux 3.16
  3. Enabling HyperZ Is Still An Easy Way For Faster RadeonSI Performance
  4. AMD Kaveri: Catalyst vs. RadeonSI Gallium3D On Linux
Latest Linux News
  1. Qt5 Will Now Support LGPLv3 Modules
  2. Proposed: A Tainted Performance State For The Linux Kernel
  3. Systemd 216 Piles On More Features, Aims For New User-Space VT
  4. Mesa 10.2.6 Has Plenty Of OpenGL Driver Bug Fixes
  5. LXQt 0.8 Is Being Released Soon
  6. Linux 3.17 Lands Memfd, A KDBUS Prerequisite
  7. Humble Jumbo Bundle 2 Shafts Linux Gamers
  8. New VM Software Claims To Be 4.5x Faster Than QEMU
  9. Btrfs Gets Talked Up, Googler Encourages You To Try Btrfs
  10. Mesa Now Supports Another OpenGL 4.5 Extension
Latest Forum Discussions
  1. Remote gui not accessible in Phoronix Test Suite 5.2
  2. The dangers of Linux kernel development
  3. Dead Island for Linux (?)
  4. Updated and Optimized Ubuntu Free Graphics Drivers
  5. AMD Offers Mantle For OpenGL-Next, Pushes Mantle To Workstations
  6. Next-Gen OpenGL To Be Announced Next Month
  7. OpenGL 4.5 Released With New Features
  8. Updated graphics drivers for Ubuntu 12.04 Precise LTS