Press Briefing - Khronos Group- Sharing textures and renderbuffers •Context Robustness - Defending...

© Copyright Khronos Group 2014 -

Press Briefing GDC, March 2014

Neil Trevett Vice President Mobile Ecosystem, NVIDIA

President Khronos


Lots of Khronos News at GDC! • OpenGL ES 3.1 Released

- Compute shaders & enhanced rendering coming to over a billion mobile devices

• OpenGL Momentum

- Developer tools and insights into low-overhead drivers

• EGL 1.5 Released

- Enhanced rendering, interop and system portability

• OpenCL 2.0 Adopters Program Released

- Full OpenCL 2.0 conformance tests available

• WebCL 1.0 Released

- Web developers to get access to heterogeneous parallel computing

• SYCL 1.2 Provisional Released

- Enabling high-level, C++ frameworks over OpenCL


Speakers This Morning • Neil Trevett

- Vice President Mobile Ecosystem, NVIDIA

- President, Khronos

- Chair, OpenCL Working Group

• Tom Olson

- Director of Graphics Research at ARM Media Processing Division

- Chair, OpenGL ES Working Group

• Andrew Richards

- CEO, Codeplay

- Chair, SYCL Working group

• Jon Peddie

- Founder and President, Jon Peddie Research

• David Cole

- Founder and CEO, DFC Intelligence


Khronos Connects Software to Silicon

Open Consortium creating

ROYALTY-FREE, OPEN STANDARD

APIs for hardware acceleration

Defining the roadmap for

low-level silicon interfaces

needed on every platform

Graphics, compute, rich media,

vision, sensor and camera

processing

Rigorous specifications AND

conformance tests for cross-

vendor portability

Acceleration APIs

BY the Industry

FOR the Industry

Well over a BILLION people use Khronos APIs

Every Day…


Khronos Standards

Visual Computing - 3D Graphics - Heterogeneous Parallel Computing

3D Asset Handling - 3D authoring asset interchange

- 3D asset transmission format with compression

Acceleration in HTML5 - 3D in browser – no Plug-in

- Heterogeneous computing for JavaScript

Camera

Control API

Over 100 companies defining royalty-free

APIs to connect software to silicon

Sensor Processing - Vision Acceleration - Camera Control - Sensor Fusion


OpenGL ES 3.1 Tom Olson, Director of Graphics Research at ARM

Media Processing Division Chair, OpenGL ES Working Group


OpenGL ES 3.1 Launched at GDC!

• OpenGL ES is used by over a BILLION users every day

- Used in almost every mobile device – phones, tablets, embedded, more…

• Introducing OpenGL ES 3.1 at GDC!

- A significant upgrade in functionality coming for a huge number of users

• Expecting rapid adoption

- A driver upgrade for many SOCs

- Backward compatible with 2.0/3.0 so apps can incrementally adopt features

2002 Working

Group

Formed

2003

1.0

2004

1.1

2007

2.0

2012

3.0

2014

3.1

Driver

Update

Silicon

Update

Silicon

Update

Driver

Update


OpenGL ES 3.1 Goals

• Bringing developer requested features from desktop OpenGL 4 to mobile

- Advanced features, modern programming styles

- Higher performance with lower overhead

• Headline features - Compute Shaders and Draw-Indirect

- Compute shaders can create geometry or other rendering data

- …and also the draw commands needed to render them

- Offload work from CPU to GPU – critical for mobile perf and power

• Run on OpenGL ES 3.0 hardware – expose hidden capabilities of shipping devices

- Enable very rapid adoption across the industry

• Better looking, faster performing apps!


• API and shading language specifications ratified and released

- Manual pages also available

• Conformance test is code complete

- Expect to be accepting conformance submission within three months

• Widespread industry participation

- Tool and Game Engine Developers

- GPU Designers

- SoC Vendors

- Platform Owners

- End Equipment Makers

- Middleware ISVs

Apple

Key Working Group Status and Participants

http://www.amd.com/

http://www.google.com/


Other OpenGL ES 3.1 Key Features • Separate shader objects

- Vertex and fragment shaders treated as separate programs

- Applications can mix and match shaders with compatible interfaces

- Supports popular console / PC programming styles

• Texture gather

- Read texture samples from a 2x2 pixel block

- Supports fast PCF shadow filtering, other applications

• New texture types

- Multi-sampled textures, packed depth/stencil textures

• Language features

- Multidimensional arrays, bitfield operations, synchronization primitives


OpenGL ES 3.1 Optional Extensions • Useful functionality that may be headed to future core releases

• Image atomics

- Special shading language functions for atomic operations on images

• Multi-sampled array textures

• Advanced blending modes

- Supports compositing APIs found in UI, web standards, and 2D art pipelines

• Sample shading

- Fragment shader can run per-sample in multi-sampled rendering

• Stand-alone 8-bit stencil textures


OpenGL ES 3.1 Desktop Compatibility • ARB_ES_3_1_compatibility specification

- Under development

• Will enable desktop drivers to be used for mobile development

- OpenGL 4.4 drivers will be able to support “OpenGL ES 3.1 context”

• Adds features missing in OpenGL

- New function MemoryBarrierByRegion()

- Raise minimum SSBO size to 128 MB

- Support for GLSL ES version 310 - ImageAtomicExchange()

- Extend mix() to int, uint and bool

- gl_helperInvocation

- gl_MaxSamples

- Adds several gl_Max*ImageUniforms builtins

- gl_MaxCombinedShaderOutputResources


OpenGL Ecosystem News • Valve’s VOGL – OpenGL capture / playback debugger

- OpenGL 3.3, OpenGL 4 in progress

- Now on github!

• Valve’s ToGL

- Subset of Direct3D 9.0c -> OpenGL

- API and DX bytecode

- On github

• SIGGRAPH course Introduction to OpenGL programming

- Free on youtube

• OpenTK updated to OpenGL 4.4

- Low-level C# library that wraps OpenGL and more

https://github.com/ValveSoftware/vogl

https://github.com/ValveSoftware/ToGL

https://www.youtube.com/watch?v=T8gjVbn8VBk


OpenGL and Reducing Driver Overhead • Because driver overhead == cost

• Costs

- CPU cycles from app

- CPU cache from app

- Power / battery

- GPU throughput

• Can we drive driver overhead to ZERO?

- In OpenGL!


OpenGL Fallacy: Old and Inefficient

Immediate Mode Fixed

Function

Ancient crufty stuff

Feedback

Selection

Evaluators

Display Lists

Selectors


OpenGL Reality: Modern & Efficient

Bindless ARB

SSBO GL4.3

Multi-Draw Indirect GL4.3

UBO GL3.1

Texture Arrays GL3.0

Buffer Storage GL4.4


Plus, OpenGL has all the features

Compute

Tessellation

Geometry Shaders

Sparse Textures

Image Load/Store


indirect draw

buffer object

buffer object

texture object

buffer object

buffer object

texture object

buffer object

buffer object

buffer object

render target

buffer object

Classic OpenGL Model

CPU

GPU

…

…

Memory

cmd

cmd

cmd

cmd

Direct Drawing Commands

(via the command fifo)


indirect draw

buffer object

indirect draw

buffer object

texture object

buffer object

indirect draw

buffer object

texture object

buffer object

buffer object

buffer object

render target

buffer object

Efficient OpenGL Model

CPU

CPU

CPU

CPU

GPU

…

…

Memory

CPU Writes Memory –

multi-threaded (no API)!

GPU Writes Commands to Memory

Reads Commands from Memory

No API – Minimal CPU Involvement

Memory access

mediated through

OpenGL fences


Results • OpenGL enables scalable multi-threading with no new API

- CPU and GPU Cores just write to memory

- GPU work creation - builds buffers, constructs MDI commands

• Integer multiple speedups ~5x – ~15x (not a typo)

- On driver limited cases, obviously

• Works TODAY on existing drivers!

- Mostly OpenGL 4.2+

- Extensions are at least EXT

• Does not require a new object model

- Does not require breaking existing applications

“Approaching Zero Driver Overhead in OpenGL”

NVIDIA, AMD, Intel presenting

Thursday 1PM, Room 2004, West Hall


EGL 1.5 Released • EGL 1.5 brings functionality from

multiple extensions into core

- Increased reliability and portability

• EGLImages

- Sharing textures and renderbuffers

• Context Robustness

- Defending against malicious code

• EGLSync objects

- Improved OpenGL /OpenCL interop

• Platform extensions

- Standardized interactions for multiple

OS e.g. Android and 64-bit platforms

• sRGB colorspace rendering

Applications

OS and Display

Platforms

Application Portability EGL abstracts graphics context

management, surface and

buffer binding and rendering synchronization

API Interop EGL provides efficient

transfer of data and events

between Khronos APIs


OpenCL: Portable Heterogeneous Computing • Portable Heterogeneous programming of diverse compute resources

- Targeting supercomputers -> embedded systems -> mobile devices

• One code tree can be executed on CPUs, GPUs, DSPs and hardware

- Dynamically interrogate system load and balance work across available processors

• OpenCL = Two APIs and C-based Kernel language

- Kernel language - Subset of ISO C99 + language extensions

OpenCL

Kernel

Code

OpenCL

Kernel

Code

OpenCL

Kernel

Code

OpenCL C

Kernel

Code

GPU

DSP CPU

CPU HW

C Platform API To query, select and initialize

compute devices

C Runtime API To build and execute kernels

across multiple devices


OpenCL 2.0 Adopters Program Launched • Official conformance test suite for the OpenCL 2.0 specification

- Implementers can certify that their implementations are officially conformant

• Released a set of header files for OpenCL 2.0

- Available on www.khronos.org

• Updated OpenCL 2.0 specification

- Clarifications and corrections to the specification first released in November 2013

• First conformant implementations of OpenCL 2.0 expected to be

available to developers in the first half of 2014

http://www.khronos.org/


WebCL: Heterogeneous Computing for the Web • WebCL 1.0 specification officially finalized today at GDC!

- https://www.khronos.org/webcl

• WebCL defines JavaScript binding to the OpenCL APIs

- Enables initiation of Kernels written in OpenCL C within the browser

• Typical Use Cases

- 3D asset codecs, video codecs and processing, imaging and vision processing

- Physics for WebGL games, Online data visualization, Augmented Reality

OpenCL

Kernel

Code

OpenCL

Kernel

Code

OpenCL

Kernel

Code

OpenCL C

Kernel

Code

GPU

DSP CPU

CPU HW

JavaScript Platform API To query, select and initialize

compute devices

JavaScript Runtime API To build and execute kernels

across multiple devices

https://www.khronos.org/webcl


Content

JavaScript, HTML, CSS, ...

WebGL/WebCL Ecosystem

JavaScript Middleware

JavaScript HTML5

/ CSS

Browser provides WebGL and WebCL Alongside other HTML5 technologies

No plug-in required

OS Provided Drivers WebGL uses OpenGL ES 2.0 or

Angle for OpenGL ES 2.0 over DX9

WebCL uses OpenCL 1.X

Content downloaded from the Web

Middleware can make WebGL and WebCL

accessible to non-expert programmers E.g. three.js library: http://threejs.org/ used by

majority of WebGL content

Low-level APIs provide

a powerful foundation

for a rich JavaScript

middleware ecosystem

http://code.google.com/p/angleproject/

http://threejs.org/

http://threejs.org/

http://threejs.org/


WebCL Architectural Security Designed-in • Leverages OpenCL 1.2 robustness/security extensions

- Context Termination: to prevent DoS from long running kernels

- Memory Initialization: no leakage from out of bounds memory access

• WebCL Kernel Validator https://github.com/KhronosGroup/webcl-validator

- Open source - provided as a “library API” for easy integration into browsers

- Parses and validates kernel code against specification

- Initializes local/private memory if underlying OpenCL implementation does not

- Tracks memory allocations and traces valid ranges for reads and writes

- Run time checks to make all memory accesses safe

• API and Language Restrictions

- Not supported: structures as Kernel arguments, Kernel names>256 characters,

mapping of CL memory objects into host memory, program binaries,

some OpenCL API calls and built-ins

https://github.com/KhronosGroup/webcl-validator




Open Source Implementations and Resources • WebCL Conformance Framework and Test Suite (contributed by Samsung)

- https://github.com/KhronosGroup/WebCL-conformance/

• Nokia - Firefox build with integrated WebCL

- Firefox extension, open sourced May 2011 (Mozilla Public License 2.0)

- https://github.com/toaarnio/webcl-firefox

• Samsung - uses WebKit, open sourced June 2011 (BSD)

- https://github.com/SRA-SiliconValley/webkit-webcl

• Motorola Mobility - uses Node.js, open sourced April 2012 (BSD)

- https://github.com/Motorola-Mobility/node-webcl

• AMD – uses Chromium (open source)

- https://github.com/amd/Chromium-WebCL

http://fract.ured.me/ Based on Iñigo Quilez, Shader Toy Based on Apple QJulia Based on Iñigo Quilez, Shader Toy

https://github.com/KhronosGroup/WebCL-conformance/



https://github.com/toaarnio/webcl-firefox



https://github.com/SRA-SiliconValley/webkit-webcl





https://github.com/Motorola-Mobility/node-webcl





https://github.com/amd/Chromium-WebCL



http://fract.ured.me/


WebCL Parallel Computing for Web Acceleration

http://www.youtube.com/user/SamsungSISA#p/a/u/1/9Ttux1A-Nuc

http://www.youtube.com/user/SamsungSISA




OpenCL as Parallel Compute Foundation • 100+ tool chains and languages leveraging OpenCL

- Heterogeneous solutions emerging for the most popular programming languages

JavaScript

binding to

OpenCL

WebCL River Trail

Language

extensions to

JavaScript

C++ AMP

Shevlin Park

Uses Clang

and LLVM

OpenCL provides vendor optimized,

cross-platform, cross-vendor access to

heterogeneous compute resources

Harlan

High level

language for GPU

programming

Compiler

directives for

Fortran C and C++

Aparapi

Java language

extensions for

parallelism

PyOpenCL

Python wrapper

around

OpenCL

Image

Processing

Language

Halide

Device X Device Y Device Z


Widening OpenCL Ecosystem


OpenCL C

Kernel Source

SPIR Generator (e.g. patched Clang)

Alternative

Language for

Kernels

Alternative

Language for

Kernels

Alternative

Language for

Kernels

High-level

Frameworks High-level

Frameworks Apps and

Frameworks

OpenCL C

Runtime

OpenCL run-time

can consume SPIR

SPIR Standard Portable

Intermediate Representation

SPIR 1.2 Released

January 2014

SYCL Programming abstraction that combines

portability and efficiency of OpenCL with

ease of use and flexibility of C++

SPIR 1.2 Released

here at GDC!


SPIR and LLVM • SPIR 1.2

- Portable non-source encoding for OpenCL 1.2 device programs

• LLVM is an optimizing compiler toolkit

- Open source platform for innovation that is portable, flexible, well understood

- SPIR based on LLVM 3.2 with open consultation with LLVM community

• Consumption API for target hardware

- cl_khr_spir extension to OpenCL runtime API

• Example SPIR generator

- Open source patch to Clang translates OpenCL C to SPIR IR

- https://github.com/KhronosGroup/SPIR

If you can do it in OpenCL C

You can do it in SPIR

https://github.com/KhronosGroup/SPIR


SYCL for OpenCL Andrew Richards, CEO Codeplay

Chair, SYCL Working group GDC, March 2014


Where is OpenCL today? • OpenCL: supported by a very wide

range of platforms

- Huge industry adoption

• Provides a C-based kernel language

• NEW: SPIR provides ability to build other

languages on top of OpenCL run-time

• Now, we need to provide additional

languages and libraries

• Topic for today: C++

OpenCL C

Kernels

Other Language

Kernels


OpenCL

Runtime


SYCL for OpenCL • Pronounced ‘sickle’

- To go with ‘spear’ (SPIR)

• Royalty-free, cross-platform C++

programming layer

- Builds on portability and

efficiency of OpenCL

- Ease of use and flexibility of C++

• Single-source C++ development

- C++ template functions can contain

host & device code

- Construct complex reusable algorithm

templates that use OpenCL for

acceleration

OpenCL C

Kernels


OpenCL

Runtime

High-level

Frameworks High-level

Frameworks C++ Based Apps

& Frameworks


Enabling C++ within OpenCL Ecosystem • Want C++ code to be portable to OpenCL

- C++ libraries supported on OpenCL

- C++ tools supported on OpenCL

• Aim to achieve long-term support for OpenCL features with C++

- Good performance of C++ software on OpenCL

• Multiple sources of implementations and enable future innovation

- Allows innovators in C++ for heterogeneous devices to leverage an open standard

- Example of what can be done now OpenCL supports multiple languages with SPIR

• Developers can now use OpenCL as the basis for a whole range of innovations in

software for heterogeneous systems


Simple Example #include <CL/sycl.hpp>

int main ()

{

int result; // this is where we will write our result

{ // by sticking all the SYCL work in a {} block, we ensure

// all SYCL tasks must complete before exiting the block

// create a queue to work on

cl::sycl::queue myQueue;

// wrap our result variable in a buffer

cl::sycl::buffer<int> resultBuf (&result, 1);

// create some ‘commands’ for our ‘queue’

cl::sycl::command_group (myQueue, [&] ()

{

// request access to our buffer

auto writeResult =

resultBuf.access<cl::sycl::access:write_only> ();

// enqueue a single, simple task

single_task(kernel_lambda<class simple_test>([=] ()

{

writeResult [0] = 1234;

}

}); // end of our commands for this queue

} // end scope, so we wait for the queue to complete

printf (“Result = %d\n”, result);

}

Does everything* expected of an

OpenCL program: compilation,

startup, shutdown, host fall-back,

queue-based parallelism, efficient

data movement.

* (this sample doesn’t catch exceptions)


What Now? • We are releasing this provisional specification to get feedback from developers

- So please give feedback!

- Khronos forums are the best place

- http://www.khronos.org/opencl/sycl

• Next steps

- Full specification, based on feedback

- Conformance test suite to ensure compatibility between implementations

• Release of implementations

- Codeplay is working on an implementation

- Anyone can implement it - it’s an open, royalty-free standard!

• Roadmap

- OpenCL working group considering C++ as kernel language - Complementary to SPIR

- SPIR 2.0 and SYCL 2.0 for use with OpenCL 2.0

http://www.khronos.org/opencl/sycl

Press Briefing - Khronos Group- Sharing textures and renderbuffers •Context Robustness - Defending...

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