[Mesa-dev] [PATCH 00/21] deferred and threaded glCompileShader

[Chia-I Wu]

Hi list,

This series adds a thread pool to the GLSL compiler, and a drirc option to
defer glCompileShader calls to the pool.  The goal is to reduce the start-up
time of applications that are aware of this feature.  That is, applications
that compile shaders first and check the compile status later.

I do not have numbers from real applications yet.  But trying to compiling a
set of 2882 shaders extracted from some trace file, with everything else
idled, the time it takes is

  8 threads: 17.8s
  4 threads: 20.3s
  2 threads: 31.2s
  1 threads: 58.0s
  no thread pool: 54.5

on a quad core system.

Patches 1-4 fix potential races in the GLSL compiler.  As the compiler is
already shared by all contexts, these patches could be desirable even without
the thread pool that I am going to add.

Patches 5-18 adds true GL_DEBUG_OUTPUT_SYNCHRONOUS support to the KHR_debug
code.  All except patch 18 are clean-ups.  Patch 18 adds a mutex to protect
gl_debug_state.

Patch 19 defines a simple API to create and work with thread pools, as well as
a test for the API.

Patch 20 adds the singleton GLSL thread pool and allows glCompileShader to be
deferred to the pool.  This feature needs to be explicitly enabled with
_mesa_enable_glsl_threadpool.

Patch 21 adds a drirc option to enable the thread pool.  The idea is that only
applications that can benefit from it will enable it.