Switch NCCL to build from open source (version 2.3.5-5) by default.
Note to users manually patching ptxas from a later toolkit version:
Building NCCL requires the same version of ptxas and nvlink.
PiperOrigin-RevId: 215911973
diff --git a/configure.py b/configure.py
index a88fdb3..65b4622 100644
--- a/configure.py
+++ b/configure.py
@@ -35,7 +35,6 @@
_DEFAULT_CUDA_VERSION = '9.0'
_DEFAULT_CUDNN_VERSION = '7'
-_DEFAULT_NCCL_VERSION = '2.2'
_DEFAULT_CUDA_COMPUTE_CAPABILITIES = '3.5,7.0'
_DEFAULT_CUDA_PATH = '/usr/local/cuda'
_DEFAULT_CUDA_PATH_LINUX = '/opt/cuda'
@@ -1109,18 +1108,17 @@
raise ValueError('Currently NCCL is only supported on Linux platforms.')
ask_nccl_version = (
- 'Please specify the NCCL version you want to use. If NCCL %s is not '
- 'installed, then you can use version 1.3 that can be fetched '
- 'automatically but it may have worse performance with multiple GPUs. '
- '[Default is %s]: ') % (_DEFAULT_NCCL_VERSION, _DEFAULT_NCCL_VERSION)
+ 'Please specify the locally installed NCCL version you want to use. '
+ '[Default is to use https://github.com/nvidia/nccl]: ')
for _ in range(_DEFAULT_PROMPT_ASK_ATTEMPTS):
tf_nccl_version = get_from_env_or_user_or_default(
- environ_cp, 'TF_NCCL_VERSION', ask_nccl_version, _DEFAULT_NCCL_VERSION)
- tf_nccl_version = reformat_version_sequence(str(tf_nccl_version), 1)
+ environ_cp, 'TF_NCCL_VERSION', ask_nccl_version, '')
- if tf_nccl_version == '1':
- break # No need to get install path, NCCL 1 is a GitHub repo.
+ if not tf_nccl_version:
+ break # No need to get install path, building the open source code.
+
+ tf_nccl_version = reformat_version_sequence(str(tf_nccl_version), 1)
# Look with ldconfig first if we can find the library in paths
# like /usr/lib/x86_64-linux-gnu and the header file in the corresponding
@@ -1232,7 +1230,6 @@
environ_cp['TF_NCCL_VERSION'] = tf_nccl_version
write_action_env_to_bazelrc('TF_NCCL_VERSION', tf_nccl_version)
-
def get_native_cuda_compute_capabilities(environ_cp):
"""Get native cuda compute capabilities.