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TL/CUDA: enable NVLS build by default #1200

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janjust merged 1 commit into from
Feb 12, 2026
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TL/CUDA: enable NVLS build by default #1200

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61 changes: 43 additions & 18 deletions config/m4/nvls.m4
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Original file line number Diff line number Diff line change
Expand Up @@ -7,11 +7,18 @@ AC_DEFUN([CHECK_NVLS],[
AS_IF([test "x$nvls_checked" != "xyes"],[
nvls_happy="no"

# Use "check" as default to auto-detect NVLS support
# "yes" = user explicitly requested --with-nvls (error if unavailable)
# "no" = user explicitly requested --without-nvls (skip entirely)
# "check" = auto-detect (enable if available, silently disable if not)
AC_ARG_WITH([nvls],
[AS_HELP_STRING([--with-nvls], [Enable NVLS (NVLINK SHARP) support (default is no).])],
[], [with_nvls=no])
[AS_HELP_STRING([--with-nvls], [Enable NVLS (NVLINK SHARP) support (default is auto-detect).])],
[], [with_nvls=check])

AS_IF([test "x$with_nvls" != "xno"],
AS_IF([test "x$with_nvls" = "xno"],
[
AC_MSG_NOTICE([NVLS was explicitly disabled])
],
[
save_CPPFLAGS="$CPPFLAGS"
save_CFLAGS="$CFLAGS"
Expand All @@ -22,40 +29,58 @@ AS_IF([test "x$nvls_checked" != "xyes"],[
# Check for CUDA 12.0+ which supports NVLS
AS_IF([test $CUDA_MAJOR_VERSION -ge 12],
[
nvls_happy="yes"
AC_DEFINE([HAVE_NVLS], [1], [Enable NVLS support])
# NVLS kernels use multimem PTX instructions which require sm_90+
# Check if NVCC_ARCH includes sm_90 or higher (90, 100, 110, 120)
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nvls_arch_supported="no"
AS_IF([echo "$NVCC_ARCH" | grep -E "sm_(9[[0-9]]|1[[0-9]][[0-9]])" >/dev/null 2>&1],
[nvls_arch_supported="yes"])

AS_IF([test "x$nvls_arch_supported" = "xyes"],
[
nvls_happy="yes"
AC_DEFINE([HAVE_NVLS], [1], [Enable NVLS support])
],
[
nvls_happy="no"
AS_IF([test "x$with_nvls" = "xyes"],
[
AC_MSG_ERROR([NVLS support is requested but target architecture does not support it. NVLS requires sm_90 (Hopper) or later. Current NVCC_ARCH: $NVCC_ARCH])
],
[
AC_MSG_NOTICE([NVLS requires sm_90 (Hopper) or later architecture, but NVCC_ARCH does not include it: $NVCC_ARCH])
])
])
],
[
nvls_happy="no"
AC_MSG_WARN([NVLS requires CUDA 12.0 or later, but CUDA $CUDA_MAJOR_VERSION.$CUDA_MINOR_VERSION was detected])
AS_IF([test "x$with_nvls" = "xyes"],
[
AC_MSG_ERROR([NVLS support is requested but NVLS cannot be enabled. Requires CUDA 12.0 or later (detected: $CUDA_MAJOR_VERSION.$CUDA_MINOR_VERSION).])
],
[
AC_MSG_NOTICE([NVLS requires CUDA 12.0 or later, but CUDA $CUDA_MAJOR_VERSION.$CUDA_MINOR_VERSION was detected])
])
])
],
[
nvls_happy="no"
AS_IF([test "x$with_nvls" = "xyes"],
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[
AC_MSG_ERROR([NVLS support is requested but CUDA is not available. NVLS requires CUDA 12.0 or later.])
])
])

AS_IF([test "x$nvls_happy" = "xyes"],
[
AC_MSG_RESULT([NVLS support: enabled])
],
[
AS_IF([test "x$with_nvls" = "xyes"],
[
AC_MSG_ERROR([NVLS support is requested but NVLS cannot be enabled. Requires CUDA 12.0 or later (detected: $CUDA_MAJOR_VERSION.$CUDA_MINOR_VERSION).])
],
[
AC_MSG_WARN([NVLS not available - requires CUDA 12.0+ with NVLS support])
nvls_happy="no"
])
AC_MSG_RESULT([NVLS support: disabled])
])

CFLAGS="$save_CFLAGS"
CPPFLAGS="$save_CPPFLAGS"
LDFLAGS="$save_LDFLAGS"

],
[
AC_MSG_WARN([NVLS was explicitly disabled])
])

nvls_checked=yes
Expand Down