Profiler improvements
* Add events for CUDA kernel start and end.
* Allow network plugins to generate profiling events
* Enable profiling on a per-operation basis, rather than per-communicator.
* Add support for graph capturing.
Add implicit launch order
* Allow to prevent deadlocks when using multiple NCCL communicators per
device by implicitly ordering NCCL operations using the host program
order. Disabled by default, set NCCL_LAUNCH_ORDER_IMPLICIT=1 to enable.
* Add a complementary mechanism to detect host threads racing to launch
to the same device. Enabled by default, set NCCL_LAUNCH_RACE_FATAL=0 to
disable.
Optimize the PAT algorithm
* Separate the computation and execution of PAT steps on different warps,
allowing to run up to 16 PAT steps in parallel to significantly
accelerate PAT and reduce its linear part.
Add support for setting QoS per communicator
* Add a new trafficClass field to the communicator configuration, to
allow the application to select a particular traffic class for a
given communicator. The meaning of the traffic class is
network-specific and should be set in accordance with the network
configuration.
* For the IB/RoCE plugin, existing config variables such as NCCL_IB_SL
and NCCL_IB_TC take precedence.
Allow to enable GPU Direct RDMA specifically on C2C platforms
* Disabled by default, set NCCL_NET_GDR_C2C=1 to enable.
Do not disable user buffer registration unless PXN is really used
* Only disable UB when a communicator has more than one rank per
node on any node.
RAS subsystem improvements
* Report operation counts separately for each collective operation type.
* Provide details about missing communicator ranks and reliably
distinguish ranks that are no longer a given communicator's members
(now reported as NOCOMM) from those that failed to respond.
Add support for timestamps to NCCL diagnostic messages
* On by default for WARN messages; NCCL_DEBUG_TIMESTAMP_LEVELS can be
used to enable them for other debug levels as well.
* The format can be changed using the NCCL_DEBUG_TIMESTAMP_FORMAT config
variable.
Reduce the memory usage with NVLink SHARP (NVLS)
* Potentially save hundreds of MBs of device memory, considering the
multicast buffer size granularity separately from the address alignment.
Update performance tuning for recent Intel CPUs
* Improve algorithm/protocol selection on recent CPUs such as Emerald
Rapids and Sapphire Rapids.
Improve channel scheduling when mixing LL and Simple operations.
* Make LL operations account for 4x more traffic to ensure LL and simple
operations complete at the same time.
Refactor the plugin code
* Clean up and harmonize the support code across the network, tuner,
and profiler plugins.
Add support for comment lines (starting with #) in the nccl.conf file
* Issue #1540.
Make user buffer registration problems print an INFO instead of a WARN.
Drop support for network plugin interface version 5.
Fix a race condition with split-shared communicators
* NCCL could hang during connection setup if multiple communicators
were grouped together that share resources.
Fix a performance regression when using NCCL_CROSS_NIC=1
* NCCL would unnecessarily alternate rings, breaking the GPU-NIC
associations.
Make GID index detection code more resilient
* Dynamic GID detection code was giving up too soon if the
detected index was not available (e.g., wasn't mapped to the
container's sysfs).
* Issues #1538, #1573.
Fix a race condition with non-blocking operation
* Fix issue when creating a non-blocking communicator after a non-
blocking collective operation on another communicator.
Fix shared memory usage on recent Blackwell GPUs.
* Issues NVIDIA/nccl-tests#287, NVIDIA/nccl-tests#291, #1637.
Fix an error with NIC fusion and IB SHARP when recreating communicators
* Disable the unloading of network plugins
Make the auto-merge failures in the NIC fusion non-fatal
* This could happen when trying to merge IB and RoCE devices.
Fixes to ncclCommAbort
* Fix hangs due to the progress thread spinning indefinitely on the
network progress.
* Reduce the abort time by up to two orders of magnitude.
Fix a crash when libnccl.so was dynamically unloaded
* The RAS subsystem was missing a clean-up handler.
Fix a hang if the network plugin's test() call returns an error.
Fix a hang on heterogeneous architectures
* Ensure we harmonize the tuning to avoid different tuning choices,
causing a hang.
Fix double-free on failed ncclCommInitRank and ncclCommFinalize.
Fix a potential list traversal bug during a group launch of multiple
communicators
* Issue #1599.
Unify the handling of NCCL configuration variables
* Under rare circumstances, some variables specified in the config file
could be ignored.
* misc/msccl: read graphCaptureStatus for every collective call
* fix a bug in checking whether UBR is enabled in MSCCLPP
* cmake: Fix patch reversal order
* misc/msccl: add logging
* erase handle key from mscclpp communicator during deregistration
* remove check on buffer size being a multiple of 32 from registration/deregistration routines since these checks are applied during enqueue
* add check for greater than zero buffer size in mscclpp registration
* Fix collective trace
* Use nontemporal for st_global
* Fix previous commit
* Add HDP flush to data receive path
* Fix previous commit
* Control flushing by NCCL_NET_FORCE_FLUSH and RCCL_NET_HDP_FLUSH
* Introduce RCCL_NET_HDP_FLUSH and RCCL_NET_GDR_FLUSH
Both are on by default. Turn both off will skip all flush will likely
result in data error.
* Enable GDR copy by default
* Remove GDR flush env var because it is disabled by GDC flush
* Output kernel collective trace at comm destroy by default
* Limit kernel timeout messages to 100
* Use system relaxed atomic for loadInt
* Refine timeout messages and use atomic for setting offset from CPU
* Add kernel trace for barrier timeout
* Add backup barrier to avoid race in atomicAdd
* Use different counters for different warps
* Rework barrier implementation
* Fix for other GFX
* Use __hip_atomic_store and __hip_atomic_load
* Fix bug in previous commit
* Don't reset barrier values in running kernel
* Update trace format
* Fix typo
* Switch back to hip_atomic_fetch_add
* Use same barrier implementation for all GFX
* Remove extra threadfence
* Turn off HDP flush by default
Please use RCCL_NET_HDP_FLUSH=1 to switch on HDP flush
* Remove unnecessary changes from alterative barrier implementation
* Added back __threadfence_block
* Revert back to threadfence for gfx other than gfx94x
Add Blackwell/SM100 support
* Add compilation for sm100
* Add graph search speeds for Blackwell
* Optimize graph search to converge on large NVLink domains
* Limit NVLS heads to 32
* Increase various limits to fit large NVLink domains
* Add extra checks for IMEX setup, needed for MNNVL
* Increase MAXCHANNELS to 64
Extend NVTX instrumentation to track NCCL communicators
* Add communicator ID to NVTX traces to allow for correlation
between ranks.
RAS fixes
* Added RCCL env params to control setting the SO_REUSEADDR and SO_LINGER socket options. This can allow control over the number of file descriptors created during bootstrapping.
* Casted the linger value to `int` sooner to avoid a scope of unknown typed-ness.
* Added CHANGELOG entry for this feature.
* ext-src: add MSCCLPP memory registration APIs
* update mem-reg patch with mscclpp helper routine to check if buffer is registered
* RCCL integration of MSCCL++ user-buffer registration APIs
* only include mscclpp_nccl header if ENABLE_MSCCLPP is defined
* ext-src: update mscclpp mem-reg patch
* add helper routine to patch
* check handle before MSCCL++ deregister
* fix typo to replace send buff with recv buff
* in case of no mscclpp registration, dduring deRegister call, ont fall back to rccl deRegister which will return an error
* Apply suggestions from code review
Whitespace suggestions and reducing diffs to avoid future merge conflicts
Co-authored-by: corey-derochie-amd <161367113+corey-derochie-amd@users.noreply.github.com>
* rename helper functions and change their return type
* set RCCL user-buffer registration to occur if attempting MSCCL++ registration with a buffer in managed memory
---------
Co-authored-by: isaki001 <Ioannis.Sakiotis@amd.com>
Co-authored-by: isaki001 <36317038+isaki001@users.noreply.github.com>
Co-authored-by: corey-derochie-amd <161367113+corey-derochie-amd@users.noreply.github.com>
Network user buffer support for collectives
* Leverage user buffer registration to achieve zero-copy
inter-node communications for Ring, NVLS and Collnet
Add RAS subsystem
* Create a RAS thread keeping track of all NCCL communicators.
* Add a ncclras tool contacting the RAS thread and getting a
report.
Add fp8 support
* Add support for e5m2 and e4m3 8-bit floating point operations.
* Use Tree/PAT algorithms when possible for better numerical
stability.
Add NIC fusion
* Add a NET API to ask the network plugin to fuse a set of
interfaces together.
* Fuse multiple NICs under the same PCI switch as a single,
larger NIC.
Socket connection failure retry
* Retry in case of socket connection failure (unreachable host)
* Avoid "Software caused connection abort" errors on retries
QP connection failure retry
* Retry in case of IB QP connection failure during ibv_modify_qp.
NET API improvements
* Allow plugins to force a flush in case data and completion
ordering is not guaranteed.
* Indicate when completion is not needed (e.g. for the LL128
protocol), allowing plugins to skip generating a completion.
* Allow for full offload of allgather operations when using one
GPU per node.
NCCL_ALGO/NCCL_PROTO strict enforcement
* Extend NCCL_ALGO/NCCL_PROTO syntax to be able to specify
ALGO/PROTO filters for each collective operation.
* Strictly enforce the ALGO/PROTO filters, no longer fall back
on the ring algorithm when the filtering leaves no option and
error out instead.
Enable CUMEM host allocations
* Use cumem functions for host memory allocation by default.
Improved profiler plugin API
* Avoid dependencies with NCCL includes.
* Add information on whether the buffer is registered or not
Adjust PAT tuning
* Improve transition between PAT and ring at scale.
Fix hangs when running with different CPU architectures
* Detect when we use a mix of GPU architectures
* Ensure Algo/Proto decisions are made based on that unified
state.
Fix FD leak in UDS
* Fix a leak when mapping buffers intra-node with cumem IPCs.
Fix crash when mixing buffer registration and graph buffer registration.
* Separate local and graph registration to avoid crashes when we free
buffers.
Fix user buffer registration with dmabuf
* Make ncclSend/ncclRecv communication with buffer registration functional
on network plugins relying on dmabuf for buffer registration.
Fix crash in IB code caused by uninitialized fields.
Fix non-blocking ncclSend/ncclRecv
* Fix case where ncclSend/ncclRecv would return ncclSuccess in non-blocking
mode even though the operation was not enqueued onto the stream.
* Issue #1495
Various compiler tweaks and fixes
* PR #758
Fix typo in ncclTopoPrintGraph
* Issue #1468
It seems like here wants to check xgmi_node instead. If checks node for "nvlink", it will verify the link_info everytime.
If checks node for "xgmi", when get yes answer, it won't need check vsmi topo interface.
Wenkai Du
Nilesh M Negi
Kamil Iskra
Tim
Nusrat Islam
Bertan Dogancay
Pedram Alizadeh
gilbertlee-amd
akolliasAMD
corey-derochie-amd
mberenjk
Dingming Wu
Vijay Srinivasan
isaki001
Mustafa Abduljabbar
Arm Patinyasakdikul
Sylvain Jeaugey
BertanDogancay
Luna
qiwei_ji
Xeonacid