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

Qt 5.3 Might Depend On SSE2 CPUs

Qt

Published on 11 November 2013 04:59 AM EST
Written by Michael Larabel in Qt
55 Comments

Thiago Macieira of Intel is coordinating a proposal to enable SSE2 by default for the 32-bit builds of the Qt tool-kit beginning with the Qt 5.3 release. This likely change is due to the V4 JIT engine generating floating-point math for Qt's QML only using SSE x86 registers.

Beyond the fact that the V4 JIT engine is generaBy making this change the developers assume that anyone using Qt 5.3+ will basically be on an x86 CPU from 2004 or later -- basically the Pentium 4 and Pentium M era or AMD Athlon 64. Those older users would be forced to switching over to a source-based build of Qt where they can manually disable the SSE2+ support.ting floating-point instructions in SSE registers for x86, Microsoft with Visual Studio 2012 is also using SSE2 instructions by default. This proposal is about having the Qt Project Linux 32-bit packages having SSE2 optimizations by default.

This change to use SSE2 by default would also affect source builds of the Qt source code, but the compile-time options would remain for disabling SSE2 instructions. There's also SSSE3 optimizations in Qt that are run-time checked. The proposed change isn't for the imminent release of Qt 5.2 but is anticipated for the release of Qt 5.3 in Q2'2014.

Enabling SSE2 by default in the 32-bit Linux builds will also mean all floating-point math done by Qt will be done in SSE rather than the slower x87 stack, drawhelpers are unconditionally enabled, and SSE2-based code for the Latin1 and UTF-8 codecs will always be enabled.

By making this change the developers assume that anyone using Qt 5.3+ will basically be on an x86 CPU from 2004 or later -- basicxally the Pentium 4 and Pentium M era or AMD Athlon 64. Those older users would be forced to switching over to a source-based build of Qt where they can manually disable the SSE2+ support at compile-time.

If you are a 32-bit Linux user with a CPU more than one decade old that would be affected by this change, see the SSE2 change proposal for more details.

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. Rosewill RS-MI-01: An Ultra Low-Cost Mini-ITX Chassis
  2. D-Link DCS-2330L HD Wireless Network Camera
  3. Gigabyte AM1M-S2H
  4. AMD's New Athlon/Semprons Give Old Phenom CPUs A Big Run For The Money
Latest Linux Articles
  1. AMD Catalyst 14.4 On Linux With Radeon R3 APU Graphics
  2. Red Hat Enterprise Linux 7.0 RC Benchmarks
  3. AMD Catalyst 14.4 Brings Few Linux Performance Improvements
  4. The Performance Of Fedora 20 Updated
Latest Linux News
  1. Intel Developer Proposes A New Linux CPU Load Metric
  2. R600 Gallium3D Lands Many OpenGL Fixes
  3. LLVMpipe Gallium3D Now Exposes GLSL 3.30
  4. NGINX 1.6 Brings SPDY 3.1 & Other New Features
  5. Linux Foundation Announces A Core Infrastructure Initiative
  6. More Steam Linux Tests/Benchmarks Might Be Coming
  7. NVIDIA's Amazing Single-Board ARM Computer Might Be Delayed
  8. Fedora 21 To Get A Playground, New Features
  9. PC-BSD Is Developing Its Own Desktop Environment
  10. Valve Is Bringing VOGL To Windows & Working On Regression Tests
  11. Canonical Is Taking Over Linux 3.13 Kernel Maintenance
  12. Google Web Designer Is Now Natively Available On Linux
Latest Forum Discussions
  1. Linux Kernel Developers Fed Up With Ridiculous Bugs In Systemd
  2. HTPC-upgrade advice: AMD Richland A8-7600 or Kaveri A10-6700T ???
  3. What Else Would You Like To See On Phoronix This Spring?
  4. The GNOME Foundation Is Running Short On Money
  5. The Most Amazing OpenGL Tech Demo In 64kb
  6. Announcing radeontop, a tool for viewing the GPU usage
  7. New card. Open source drivers only.
  8. Script for Fan Speed Control