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 Benchmarking Platform
Phoromatic Test Orchestration

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 Articles & Reviews
  1. Ubuntu 15.04 Offers Faster OpenGL For AMD Radeon GPUs On Open-Source
  2. Ubuntu 15.04 Brings Some Graphics Performance Improvements For Intel Haswell
  3. Sub-$20 802.11n USB WiFi Adapter That's Linux Friendly
  4. The Lenovo T450s Is Working Beautifully With Linux
  5. Linux 4.0 SSD EXT4 / Btrfs / XFS / F2FS Benchmarks
  6. Linux 4.0 Hard Drive Comparison With Six File-Systems
Latest Linux News
  1. The Difference In Optimizations Between NIR & GLSL
  2. OpenMandriva Lx 3 Alpha: Adds UEFI Support, Defaults To LXQt
  3. Systemd Kills Off Shutdownd
  4. There's Now More Than 1,100 Games On Steam For Linux
  5. Btrfs In Linux 4.1 Has Fixes For File-Systems Of 20 Terabytes & Up
  6. Microsoft's CoreCLR Now Works On FreeBSD
  7. Unigine 2.0 Beta 2 Brings PBR, SSR, Kinect 2 Support
  8. KDBUS Still Hasn't Been Pulled, Might Not Land For Linux 4.1
  9. The State Of The Lima/Tamil Driver Code
  10. The New Linux Performance Test Lab Is Already Being Expanded
Most Viewed News This Week
  1. AMD Releases New "AMDGPU" Linux Kernel Driver & Mesa Support
  2. EXT4 In Linux 4.1 Adds File-System Level Encryption
  3. AMD Open-Sources "Addrlib" From Catalyst
  4. My Favorite Computer Desk Of The Past Decade For Less Than $100
  5. Library Operating System (LibOS) For Linux Still Being Pursued
  6. Linux-Powered Endless Computer Raises $100k+ In A Few Days
  7. Features Thus Far For The Linux 4.1 Kernel
  8. GIMP's Porting To GTK3 Continues