commit	313c5239959b8f9e5cc182b982c914978f437ae1	[log] [tgz]
author	Jose M Monsalve Diaz <jmonsalvediaz@anl.gov>	Tue Jul 27 22:38:27 2021 -0400
committer	Shilei Tian <tianshilei1992@gmail.com>	Tue Jul 27 22:38:35 2021 -0400
tree	5bbe22450d38bdd6781088be4c54d7e03711c5f9
parent	fe7ca1a9fca0ccea7495224e0e837de705e69699 [diff]

[OpenMP][Tool] Introducing the `llvm-omp-device-info` tool

This patch introduces the `llvm-omp-device-info` tool, which uses the
omptarget library and interface to query the device info from all the
available devices as seen by OpenMP. This is inspired by PGI's `pgaccelinfo`

Since omptarget usually requires a description structure with executable
kernels, I split the initialization of the RTLs and Devices to be able to
initialize all possible devices and query each of them.

This revision relies on the patch that introduces the print device info.

A limitation is that the order in which the devices are initialized, and the
corresponding device ID is not necesarily the one seen by OpenMP.

The changes are as follows:
1. Separate the RTL initialization that was performed in `RegisterLib` to its own `initRTLonce` function
2. Create an `initAllRTLs` method that initializes all available RTLs at runtime
3. Created the `llvm-deviceinfo.cpp` tool that uses `omptarget` to query each device and prints its information.

Example Output:
```
Device (0):
    print_device_info not implemented

Device (1):
    print_device_info not implemented

Device (2):
    print_device_info not implemented

Device (3):
    print_device_info not implemented

Device (4):
    CUDA Driver Version:                11000
    CUDA Device Number:                 0
    Device Name:                        Quadro P1000
    Global Memory Size:                 4236312576 bytes
    Number of Multiprocessors:          5
    Concurrent Copy and Execution:      Yes
    Total Constant Memory:              65536 bytes
    Max Shared Memory per Block:        49152 bytes
    Registers per Block:                65536
    Warp Size:                          32 Threads
    Maximum Threads per Block:          1024
    Maximum Block Dimensions:           1024, 1024, 64
    Maximum Grid Dimensions:            2147483647 x 65535 x 65535
    Maximum Memory Pitch:               2147483647 bytes
    Texture Alignment:                  512 bytes
    Clock Rate:                         1480500 kHz
    Execution Timeout:                  Yes
    Integrated Device:                  No
    Can Map Host Memory:                Yes
    Compute Mode:                       DEFAULT
    Concurrent Kernels:                 Yes
    ECC Enabled:                        No
    Memory Clock Rate:                  2505000 kHz
    Memory Bus Width:                   128 bits
    L2 Cache Size:                      1048576 bytes
    Max Threads Per SMP:                2048
    Async Engines:                      Yes (2)
    Unified Addressing:                 Yes
    Managed Memory:                     Yes
    Concurrent Managed Memory:          Yes
    Preemption Supported:               Yes
    Cooperative Launch:                 Yes
    Multi-Device Boars:                 No
    Compute Capabilities:               61
```

Reviewed By: tianshilei1992

Differential Revision: https://reviews.llvm.org/D106752

10 files changed

tree: 5bbe22450d38bdd6781088be4c54d7e03711c5f9

README.md

The LLVM Compiler Infrastructure

This directory and its sub-directories contain source code for LLVM, a toolkit for the construction of highly optimized compilers, optimizers, and run-time environments.

The README briefly describes how to get started with building LLVM. For more information on how to contribute to the LLVM project, please take a look at the Contributing to LLVM guide.

Getting Started with the LLVM System

Taken from https://llvm.org/docs/GettingStarted.html.

Overview

Welcome to the LLVM project!

The LLVM project has multiple components. The core of the project is itself called “LLVM”. This contains all of the tools, libraries, and header files needed to process intermediate representations and convert them into object files. Tools include an assembler, disassembler, bitcode analyzer, and bitcode optimizer. It also contains basic regression tests.

C-like languages use the Clang front end. This component compiles C, C++, Objective-C, and Objective-C++ code into LLVM bitcode -- and from there into object files, using LLVM.

Other components include: the libc++ C++ standard library, the LLD linker, and more.

Getting the Source Code and Building LLVM

The LLVM Getting Started documentation may be out of date. The Clang Getting Started page might have more accurate information.

This is an example work-flow and configuration to get and build the LLVM source:

Checkout LLVM (including related sub-projects like Clang):
- git clone https://github.com/llvm/llvm-project.git
- Or, on windows, git clone --config core.autocrlf=false https://github.com/llvm/llvm-project.git
Configure and build LLVM and Clang:
- cd llvm-project
- cmake -S llvm -B build -G <generator> [options]
  Some common build system generators are:
  - Ninja --- for generating Ninja build files. Most llvm developers use Ninja.
  - Unix Makefiles --- for generating make-compatible parallel makefiles.
  - Visual Studio --- for generating Visual Studio projects and solutions.
  - Xcode --- for generating Xcode projects.
  Some Common options:
  - -DLLVM_ENABLE_PROJECTS='...' --- semicolon-separated list of the LLVM sub-projects you'd like to additionally build. Can include any of: clang, clang-tools-extra, libcxx, libcxxabi, libunwind, lldb, compiler-rt, lld, polly, or cross-project-tests.
    For example, to build LLVM, Clang, libcxx, and libcxxabi, use -DLLVM_ENABLE_PROJECTS="clang;libcxx;libcxxabi".
  - -DCMAKE_INSTALL_PREFIX=directory --- Specify for directory the full path name of where you want the LLVM tools and libraries to be installed (default /usr/local).
  - -DCMAKE_BUILD_TYPE=type --- Valid options for type are Debug, Release, RelWithDebInfo, and MinSizeRel. Default is Debug.
  - -DLLVM_ENABLE_ASSERTIONS=On --- Compile with assertion checks enabled (default is Yes for Debug builds, No for all other build types).
- cmake --build build [-- [options] <target>] or your build system specified above directly.
  - The default target (i.e. ninja or make) will build all of LLVM.
  - The check-all target (i.e. ninja check-all) will run the regression tests to ensure everything is in working order.
  - CMake will generate targets for each tool and library, and most LLVM sub-projects generate their own check-<project> target.
  - Running a serial build will be slow. To improve speed, try running a parallel build. That's done by default in Ninja; for make, use the option -j NNN, where NNN is the number of parallel jobs, e.g. the number of CPUs you have.
- For more information see CMake

Consult the Getting Started with LLVM page for detailed information on configuring and compiling LLVM. You can visit Directory Layout to learn about the layout of the source code tree.