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. Intel Xeon E5-1680 v3 & E5-2687W v3 Compared To The Core i7 5960X On Linux
  2. Intel 120GB 530 Series SSD Linux Performance
  3. Btrfs/EXT4/XFS/F2FS RAID 0/1/5/6/10 Linux Benchmarks On Four SSDs
  4. AMD's Windows Catalyst Driver Remains Largely Faster Than Linux Drivers
Latest Linux Articles
  1. Is The Open-Source NVIDIA Driver Fast Enough For Steam On Linux Gaming?
  2. Linux 3.18 File-System Performance Minimally Changed But Possible Regressions
  3. AMD Radeon Gallium3D Is Catching Up & Sometimes Beating Catalyst On Linux
  4. CS:GO & TF2 Extensively Tested On The Newest Open-Source Radeon Linux Driver
Latest Linux News
  1. HHVM 3.4 Adds New Features, Support
  2. More Radeon Driver Changes Queued For Linux 3.19
  3. Unigine 2.0 Alpha 2 Adds C# Support
  4. FFmpeg Is Returning To Ubuntu With 15.04 Release
  5. Linux Version Of Civilization: Beyond Earth Still Coming Along
  6. Yahoo To Become Default Search Provider For Firefox
  7. Better Fan Control Support Coming To The Open-Source Radeon Driver
  8. PTS 5.4 Milestone 6 Released - Official "Lipki" Release Is Near
  9. Ian Jackson Resigns From The Debian Technical Committee
  10. Valve's VOGL Is Finally Back To Having New Commits, OS X Support
Latest Forum Discussions
  1. Updated and Optimized Ubuntu Free Graphics Drivers
  2. Debian Init System Coupling Vote Results
  3. Ubuntu Developers Still Thinking What To Do About Adobe Flash Support
  4. Debian Developer Resigns From The Systemd Maintainership Team
  5. How to get rid of Linux
  6. how to configure module phoromatic ?
  7. Major Performance Breakthrough Discovered For Intel's Mesa Driver
  8. Script for Fan Speed Control