libc/src/time/gpu/time_utils.h

   1 //===-- Generic utilities for GPU timing ----------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #ifndef LLVM_LIBC_SRC_TIME_GPU_TIME_UTILS_H
  10 #define LLVM_LIBC_SRC_TIME_GPU_TIME_UTILS_H
  11
  12 #include "hdr/time_macros.h"
  13 #include "hdr/types/clock_t.h"
  14 #include "src/__support/GPU/utils.h"
  15 #include "src/__support/macros/config.h"
  16
  17 namespace LIBC_NAMESPACE_DECL {
  18
  19 #if defined(LIBC_TARGET_ARCH_IS_AMDGPU)
  20 // AMDGPU does not have a single set frequency. Different architectures and
  21 // cards can have different values. The actualy frequency needs to be read from
  22 // the kernel driver and will be between 25 MHz and 100 MHz on most cards. All
  23 // cards following the GFX9 ISAs use a 100 MHz clock so we will default to that.
  24 constexpr uint64_t clock_freq = 100000000UL;
  25
  26 // We provide an externally visible symbol such that the runtime can set
  27 // this to the correct value.
  28 extern "C" {
  29 [[gnu::visibility("protected")]]
  30 extern gpu::Constant<uint64_t> __llvm_libc_clock_freq;
  31 }
  32 #define GPU_CLOCKS_PER_SEC static_cast<clock_t>(__llvm_libc_clock_freq)
  33
  34 #elif defined(LIBC_TARGET_ARCH_IS_NVPTX)
  35 // NPVTX uses a single 1 GHz fixed frequency clock for all target architectures.
  36 #define GPU_CLOCKS_PER_SEC static_cast<clock_t>(1000000000UL)
  37 #else
  38 #error "Unsupported target"
  39 #endif
  40
  41 } // namespace LIBC_NAMESPACE_DECL
  42
  43 #endif // LLVM_LIBC_SRC_TIME_GPU_TIME_UTILS_H