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

VBlank Timestamping Improvements Proposed

Intel

Published on 26 October 2013 05:40 PM EDT
Written by Michael Larabel in Intel
Comment On This Article

A set of Linux kernel patches have been proposed to improve vblank time-stamping by the Linux DRM/KMS drivers. This is able to improve the precision and reliability of the KMS drivers of time-stamps for handing VBlank support.

Mario Kleiner proposed a set of kernel patches that move latency-sensitive code of the VBlank time-stamping from DRM core and into the KMS drivers. Mario has tested this with the Intel and Radeon DRM drivers and for Intel KMS the changes have been of great improvement.

Since the Linux 3.11 kernel, vblank time-stamps for the Intel driver have been "too inaccurate" and also no longer works with a PREEMPT_RT kernel. These patches also restore support for handling DRM drivers with real-time Linux kernels.

The set of four kernel patches for improving vblank timestamps can be found via the dri-devel list. There's been some code review so far on the work but no word whether it will be ready for the Linux 3.13 kernel.

Mario noted that the time-stamp uncertainty for a low-end Atom netbook went from 3-8 micro-seconds with spikes greater than 20 micro-seconds to now typically being just one micro-second and then just occassionally 2 or 3 micro-seconds.

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. Scythe Mugen MAX
  2. Intel Core i7 5960X Haswell-E On Linux
  3. Intel 80GB 530 Series M.2 SSD On Linux
  4. With A New Motherboard, The Core i7 5960X Haswell-E Lights Up
Latest Linux Articles
  1. RadeonSI Gallium3D vs. Catalyst At 4K UHD On Linux
  2. MSAA RadeonSI Gallium3D Performance Preview
  3. Intel Core i7 5960X CPU Core Scaling Under Linux
  4. AMD RadeonSI Gallium3D Performance For 4K Linux Gaming
Latest Linux News
  1. Minix 3.3 Released With Cortex-A8 ARM Support, NetBSD Userland Compatibility
  2. More Intel DRM Changes Queued For Linux 3.18, Including Old i830M Fixes
  3. New Code Starts Lining Up For X.Org Server 1.17
  4. Rust Developers Planning For The Rust 1.0 Language
  5. RPM 4.12 Brings New Switches, New Rpm2Archive Utility
  6. Nouveau For Linux 3.18 Gains DP Audio, More Re-Clocking
  7. SUSE Gets Bought Out Again
  8. Enlightenment E19 Officially Released With Its Own Wayland Compositor
  9. OpenMediaVault 1.0 Released As New Linux NAS Alternative
  10. VESA Releases DisplayPort 1.3, Pushes 32.4 Gbits/sec
Latest Forum Discussions
  1. support for first generation UVD blocks (RV6xx, RS780, RS880 and RV790)
  2. Nvidia joins the ranks of Apple and Microsoft
  3. Updated and Optimized Ubuntu Free Graphics Drivers
  4. New Group Calls For Boycotting Systemd
  5. Hd 6850
  6. nv and xorg.conf under Debian PPC
  7. X.Org Is Looking For Some Female Help
  8. FSF Issues Their Rebuttal To Apple's New iPhone, Watch & Apple Pay