llvm-project/openmp/libomptarget
Johannes Doerfert b0789a1b12 [OpenMP] Avoid costly shadow map traversals whenever possible
In the OpenMC app we saw `omp target update` spending an awful lot of
time in the shadow map traversal without ever doing any update there.
There are two cases that allow us to avoid the traversal completely.
The simplest thing is that small updates cannot (reasonably) contain
an attached pointer part. The other case requires to track in the
mapping table if an entry might contain an attached pointer as part.
Given that we have a single location shadow map entries are created,
the latter is actually fairly easy as well.

Differential Revision: https://reviews.llvm.org/D113124
2022-01-19 22:14:41 -06:00
..
DeviceRTL [OpenMP] Expand short verisions of OpenMP offloading triples 2022-01-19 20:26:37 -05:00
cmake/Modules [NFC][libomptarget] Fixed -DLLVM_ENABLE_RUNTIMES="openmp" build. 2021-06-18 09:20:10 -07:00
deviceRTLs [Libomptarget] Add `cold` to KeepAlive attributes 2022-01-17 17:29:26 -05:00
docs [NFC] Initial documentation for declare target indirect support. 2021-11-08 15:12:03 -08:00
include [OpenMP] Avoid costly shadow map traversals whenever possible 2022-01-19 22:14:41 -06:00
plugins [openmp][amdgpu] Disable tests on old runtime, enable tests on new one 2022-01-19 15:49:47 +00:00
src [OpenMP] Avoid costly shadow map traversals whenever possible 2022-01-19 22:14:41 -06:00
test [openmp] Always pass valid triple to openmp-targets when using newRTL 2022-01-19 22:07:22 +00:00
tools [OpenMP] Fixing llvm-omp-device-info compilation with runtimes 2021-07-30 13:09:08 -05:00
utils Revert "[OpenMP] Codegen aggregate for outlined function captures" 2021-09-21 13:20:39 -07:00
CMakeLists.txt Revert "[openmp] Add OMPT initialization in libomptarget" 2021-11-10 12:44:25 +01:00
README.txt

README.txt

    README for the LLVM* OpenMP* Offloading Runtime Library (libomptarget)
    ======================================================================

How to Build the LLVM* OpenMP* Offloading Runtime Library (libomptarget)
========================================================================
In-tree build:

$ cd where-you-want-to-live
Check out openmp (libomptarget lives under ./libomptarget) into llvm/projects
$ cd where-you-want-to-build
$ mkdir build && cd build
$ cmake path/to/llvm -DCMAKE_C_COMPILER=<C compiler> -DCMAKE_CXX_COMPILER=<C++ compiler>
$ make omptarget

Out-of-tree build:

$ cd where-you-want-to-live
Check out openmp (libomptarget lives under ./libomptarget)
$ cd where-you-want-to-live/openmp/libomptarget
$ mkdir build && cd build
$ cmake path/to/openmp -DCMAKE_C_COMPILER=<C compiler> -DCMAKE_CXX_COMPILER=<C++ compiler>
$ make

For details about building, please look at README.rst in the parent directory.

Architectures Supported
=======================
The current library has been only tested in Linux operating system and the
following host architectures:
* Intel(R) 64 architecture
* IBM(R) Power architecture (big endian)
* IBM(R) Power architecture (little endian)
* ARM(R) AArch64 architecture (little endian)

The currently supported offloading device architectures are:
* Intel(R) 64 architecture (generic 64-bit plugin - mostly for testing purposes)
* IBM(R) Power architecture (big endian) (generic 64-bit plugin - mostly for testing purposes)
* IBM(R) Power architecture (little endian) (generic 64-bit plugin - mostly for testing purposes)
* ARM(R) AArch64 architecture (little endian) (generic 64-bit plugin - mostly for testing purposes)
* CUDA(R) enabled 64-bit NVIDIA(R) GPU architectures

Supported RTL Build Configurations
==================================
Supported Architectures: Intel(R) 64, IBM(R) Power 7 and Power 8

              ---------------------------
              |   gcc      |   clang    |
--------------|------------|------------|
| Linux* OS   |  Yes(1)    |  Yes(2)    |
-----------------------------------------

(1) gcc version 4.8.2 or later is supported.
(2) clang version 3.7 or later is supported.


Front-end Compilers that work with this RTL
===========================================

The following compilers are known to do compatible code generation for
this RTL:
  - clang (from https://github.com/clang-ykt )
  - clang (development branch at http://clang.llvm.org - several features still
    under development)

-----------------------------------------------------------------------

Notices
=======
This library and related compiler support is still under development, so the
employed interface is likely to change in the future.

*Other names and brands may be claimed as the property of others.