Deprecate XLA_USE_BF16

TROUBLESHOOTING.md

@@ -334,25 +334,6 @@ only be enabled for debugging.
  by one. This is useful to bypass the long compilation time but overall step time will be a lot slower and memory usage will be higher
  since all compiler optimizaiton will be skipped.
 
-* ```XLA_USE_BF16```: If set to 1, transforms all the _PyTorch_ _Float_ values into _BiFloat16_
- when sending to the _TPU_ device. Note that when using `XLA_USE_BF16=1` tensor arithmetic will
- be done in reduced precision and so tensors will not be accurate if accumulated over time.
- For example:
-
- ```
- # In reduced bfloat16 precision
- >>> torch.tensor(4096, dtype=torch.bfloat16) + torch.tensor(1, dtype=torch.bfloat16)
- tensor(4096., dtype=torch.bfloat16)
- # Whereas in full float32 precision
- >>> torch.tensor(4096) + torch.tensor(1)
- tensor(4097)
- ```
- So to get accurate metrics such as average loss value over many steps, use manual mixed
- precision where metrics stay in FP32.
-
-* ```XLA_USE_F16```: If set to 1, transforms all the _PyTorch_ _Float_ values into _Float16_
- (_PyTorch_ _Half_ type) when sending to devices which supports them.
-
 * ```TF_CPP_LOG_THREAD_ID```: If set to 1, the TF logs will show the thread ID
  helping with debugging multithreaded processes.
 

torch_xla/csrc/dtype.cpp

@@ -10,6 +10,9 @@ namespace {
 bool ShouldUseBF16() {
  bool use_bf16 = runtime::sys_util::GetEnvBool("XLA_USE_BF16", false);
  if (use_bf16) {
+ std::cout
+ << "XLA_USE_BF16 will be deprecated after the 2.4 release, please "
+ "convert your model to bf16 directly\n";
  TF_LOG(INFO) << "Using BF16 data type for floating point values";
  }
  return use_bf16;
@@ -18,6 +21,9 @@ bool ShouldUseBF16() {
 bool ShouldUseF16() {
  bool use_fp16 = runtime::sys_util::GetEnvBool("XLA_USE_FP16", false);
  if (use_fp16) {
+ std::cout
+ << "XLA_USE_FP16 will be deprecated after the 2.4 release, please "
+ "convert your model to fp16 directly\n";
  TF_LOG(INFO) << "Using F16 data type for floating point values";
  }
  return use_fp16;
@@ -27,6 +33,9 @@ bool ShouldDowncastToBF16() {
  bool downcast_bf16 =
  runtime::sys_util::GetEnvBool("XLA_DOWNCAST_BF16", false);
  if (downcast_bf16) {
+ std::cout
+ << "XLA_DOWNCAST_BF16 will be deprecated after the 2.4 release, please "
+ "downcast your model directly\n";
  TF_LOG(INFO) << "Downcasting floating point values, F64->F32, F32->BF16";
  }
  return downcast_bf16;
@@ -36,6 +45,9 @@ bool ShouldDowncastToF16() {
  bool downcast_fp16 =
  runtime::sys_util::GetEnvBool("XLA_DOWNCAST_FP16", false);
  if (downcast_fp16) {
+ std::cout
+ << "XLA_DOWNCAST_FP16 will be deprecated after the 2.4 release, please "
+ "downcast your model directly\n";
  TF_LOG(INFO) << "Downcasting floating point values, F64->F32, F32->FP16";
  }
  return downcast_fp16;
@@ -45,6 +57,8 @@ bool ShouldUse32BitLong() {
  bool use_32bit_long =
  runtime::sys_util::GetEnvBool("XLA_USE_32BIT_LONG", false);
  if (use_32bit_long) {
+ std::cout
+ << "XLA_USE_32BIT_LONG will be deprecated after the 2.4 release\n";
  TF_LOG(INFO) << "Using 32bit integers for kLong values";
  }
  return use_32bit_long;