From 88a549554f1686e91525bdb2a302998f920b6cd8 Mon Sep 17 00:00:00 2001
From: Jiewen Tan <jwtan@google.com>
Date: Wed, 25 Oct 2023 14:23:05 -0700
Subject: [PATCH] Revert "Don't set $TPU_LIBRARY_PATH during import (#5698)"
 (#5731)

This reverts commit 146f2a0140c5217a31d55cfdebb1efb6bc05b41a.
---
 torch_xla/__init__.py                             | 9 +++------
 torch_xla/csrc/runtime/env_vars.cc                | 1 -
 torch_xla/csrc/runtime/env_vars.h                 | 1 -
 torch_xla/csrc/runtime/pjrt_computation_client.cc | 9 ++++-----
 4 files changed, 7 insertions(+), 13 deletions(-)

diff --git a/torch_xla/__init__.py b/torch_xla/__init__.py
index ce1787d0fe3a..eeaa2aaba0c9 100644
--- a/torch_xla/__init__.py
+++ b/torch_xla/__init__.py
@@ -72,16 +72,13 @@ def _aws_ec2_inf_trn_init():
 
 
 def _setup_tpu_vm_library_path() -> bool:
-  """Returns true if $TPU_LIBRARY_PATH is set or can be inferred.
+  """Returns true if $TPU_LIBRARY is set or can be inferred.
 
   We load libtpu.so in the following order of precedence:
 
   1. User-set $TPU_LIBRARY_PATH
   2. libtpu.so included in torch_xla/lib
   3. libtpu-nightly pip package
-
-  Sets $PTXLA_TPU_LIBRARY_PATH if path is inferred by us to prevent conflicts
-  with other frameworks. This env var will be removed in a future version.
   """
   if 'TPU_LIBRARY_PATH' in os.environ:
     return True
@@ -90,12 +87,12 @@ def _setup_tpu_vm_library_path() -> bool:
   bundled_libtpu_path = os.path.join(module_path, 'lib/libtpu.so')
   if os.path.isfile(bundled_libtpu_path) and not os.getenv('TPU_LIBRARY_PATH'):
     logger.info('Using bundled libtpu.so (%s)', bundled_libtpu_path)
-    os.environ['PTXLA_TPU_LIBRARY_PATH'] = bundled_libtpu_path
+    os.environ['TPU_LIBRARY_PATH'] = bundled_libtpu_path
     return True
 
   try:
     import libtpu
-    os.environ['PTXLA_TPU_LIBRARY_PATH'] = libtpu.get_library_path()
+    libtpu.configure_library_path()
     return True
   except ImportError:
     return False
diff --git a/torch_xla/csrc/runtime/env_vars.cc b/torch_xla/csrc/runtime/env_vars.cc
index 00ffb1f2a25f..42040a9cca5f 100644
--- a/torch_xla/csrc/runtime/env_vars.cc
+++ b/torch_xla/csrc/runtime/env_vars.cc
@@ -14,7 +14,6 @@ const char* const kEnvPjRtTpuMaxInflightComputations =
 const char* const kEnvPjrtAsyncCpuClient = "PJRT_CPU_ASYNC_CLIENT";
 const char* const kEnvPjrtAsyncGpuClient = "PJRT_GPU_ASYNC_CLIENT";
 const char* const kEnvTpuLibraryPath = "TPU_LIBRARY_PATH";
-const char* const kEnvInferredTpuLibraryPath = "PTXLA_TPU_LIBRARY_PATH";
 const char* const kEnvXpuLibraryPath = "XPU_LIBRARY_PATH";
 const char* const kEnvNeuronLibraryPath = "NEURON_LIBRARY_PATH";
 const char* const kEnvPjrtDistServiceAddr = "PJRT_DIST_SERVICE_ADDR";
diff --git a/torch_xla/csrc/runtime/env_vars.h b/torch_xla/csrc/runtime/env_vars.h
index 72849003765b..e54ba8f72cd8 100644
--- a/torch_xla/csrc/runtime/env_vars.h
+++ b/torch_xla/csrc/runtime/env_vars.h
@@ -24,7 +24,6 @@ extern const char* const kEnvPjRtTpuMaxInflightComputations;
 extern const char* const kEnvPjrtAsyncCpuClient;
 extern const char* const kEnvPjrtAsyncGpuClient;
 extern const char* const kEnvTpuLibraryPath;
-extern const char* const kEnvInferredTpuLibraryPath;
 extern const char* const kEnvXpuLibraryPath;
 extern const char* const kEnvNeuronLibraryPath;
 extern const char* const kEnvPjrtDistServiceAddr;
diff --git a/torch_xla/csrc/runtime/pjrt_computation_client.cc b/torch_xla/csrc/runtime/pjrt_computation_client.cc
index f5c7b724aace..2ae0768856b7 100644
--- a/torch_xla/csrc/runtime/pjrt_computation_client.cc
+++ b/torch_xla/csrc/runtime/pjrt_computation_client.cc
@@ -94,11 +94,10 @@ PjRtComputationClient::PjRtComputationClient() {
     client_ = std::move(xla::GetTfrtCpuClient(async, cpu_device_count).value());
   } else if (device_type == "TPU" || device_type == "TPU_C_API") {
     TF_VLOG(1) << "Initializing TFRT TPU client...";
-    // Prefer $TPU_LIBRARY_PATH if set
-    auto tpu_library_path = sys_util::GetEnvString(
-        env::kEnvTpuLibraryPath,
-        sys_util::GetEnvString(env::kEnvInferredTpuLibraryPath, "libtpu.so"));
-    XLA_CHECK_OK(pjrt::LoadPjrtPlugin("tpu", tpu_library_path).status());
+    XLA_CHECK_OK(
+        pjrt::LoadPjrtPlugin(
+            "tpu", sys_util::GetEnvString(env::kEnvTpuLibraryPath, "libtpu.so"))
+            .status());
     tsl::Status tpu_status = pjrt::InitializePjrtPlugin("tpu");
     XLA_CHECK(tpu_status.ok());
     client_ = std::move(xla::GetCApiClient("TPU").value());