Michael Halkenhaeuser 5b19f42b63 [OpenMP][AMDGPU] Single eager resource init + HSA queue utilization tracking
This patch lazily initializes queues/streams/events since their initialization
might come at a cost even if we do not use them.

To further benefit from this, AMDGPU/HSA queue management is moved into the
AMDGPUStreamManager of an AMDGPUDevice. Streams may now use different HSA queues
during their lifetime and identify busy queues.

When a Stream is requested from the resource manager, it will search for and
try to assign an idle queue. During the search for an idle queue the manager
may initialize more queues, up to the set maximum (default: 4).
When no idle queue could be found: resort to round robin selection.

With contributions from Johannes Doerfert <johannes@jdoerfert.de>

Depends on D156245

Reviewed By: kevinsala

Differential Revision: https://reviews.llvm.org/D154523
2023-08-02 08:22:26 -04:00
..
2023-07-25 13:58:49 +02:00

OpenMP LLVM Documentation
==================

OpenMP LLVM's documentation is written in reStructuredText, a lightweight
plaintext markup language (file extension `.rst`). While the
reStructuredText documentation should be quite readable in source form, it
is mostly meant to be processed by the Sphinx documentation generation
system to create HTML pages which are hosted on <https://llvm.org/docs/> and
updated after every commit. Manpage output is also supported, see below.

If you instead would like to generate and view the HTML locally, install
Sphinx <http://sphinx-doc.org/> and then do:

    cd <build-dir>
    cmake -DLLVM_ENABLE_SPHINX=true -DSPHINX_OUTPUT_HTML=true -DCMAKE_MODULE_PATH=/path/to/llvm/cmake/modules <src-dir>
    make docs-openmp-html
    $BROWSER <build-dir>/docs/html/index.html

The mapping between reStructuredText files and generated documentation is
`docs/Foo.rst` <-> `<build-dir>/projects/openmp/docs//html/Foo.html` <->
`https://openmp.llvm.org/docs/Foo.html`.

If you are interested in writing new documentation, you will want to read
`llvm/docs/SphinxQuickstartTemplate.rst` which will get you writing
documentation very fast and includes examples of the most important
reStructuredText markup syntax.

Manpage Output
===============

Building the manpages is similar to building the HTML documentation. The
primary difference is to use the `man` makefile target, instead of the
default (which is `html`). Sphinx then produces the man pages in the
directory `<build-dir>/docs/man/`.

    cd <build-dir>
    cmake -DLLVM_ENABLE_SPHINX=true -DSPHINX_OUTPUT_MAN=true <src-dir>
    make
    man -l >build-dir>/docs/man/FileCheck.1

The correspondence between .rst files and man pages is
`docs/CommandGuide/Foo.rst` <-> `<build-dir>/projects/openmp/docs//man/Foo.1`.
These .rst files are also included during HTML generation so they are also
viewable online (as noted above) at e.g.
`https://openmp.llvm.org/docs/CommandGuide/Foo.html`.