858b4e76eb3fa210704aa95514f48b8b0f2013bc
2 Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
 Mark Santesson
|
f1308997d0 |
NCCL 2.28.3-1
Device API (Experimental) * Introduces device-side APIs to integrate NCCL communication directly into application kernels. * Supports LSA (Load/Store Access) for CUDA P2P communication over NVLink and some PCIe platforms. * Supports Multimem for hardware multicast using NVLink SHARP. * Adds initial framework for GIN (GPU-Initiated Networking), currently under development. * Introduces device communicators created using ncclDevCommCreate. * Enables device-side communication operations with synchronization (ncclLsaBarrierSession) and memory accessors (ncclGetLsaPointer, ncclGetLsaMultimemPointer). * Experimental APIs - signatures and functionality may evolve in future releases. * No ABI compatibility is guaranteed — applications must be recompiled with each new NCCL release. Symmetric memory improvements * Support for aggregating symmetric operations using ncclGroupStart/End APIs. * Reimplement symmetric kernels using device API. New Host APIs * Introduce new host collective APIs: ncclAlltoAll, ncclScatter, ncclGather. CE (Copy Engine) Collectives * Reduce SM utilization for alltoall, scatter, gather, and allgather within a single (MN)NVL domain. * Free up SM capacity for the application to do computation at the same time. * To enable the feature for ncclAllGather, ncclAlltoAll, ncclGather, ncclScatter, register buffers into symmetric windows and use the NCCL_CTA_POLICY_ZERO flag in the communicator config_t. NCCL Inspector Plugin * Introduces an Inspector plugin for always-on performance monitoring. * Produces structured JSON output with metadata, execution time, bandwidth, and optional event traces for each NCCL operation. * Enables integration with analysis tools such as Performance Exporter to visualize NCCL performance bottlenecks. * Lightweight to enable via environment variables NCCL_PROFILER_PLUGIN and NCCL_INSPECTOR_ENABLE. CMake support (Experiemental) * Adds a CMake build system as an alternative to existing Makefiles. * Known issues: pkg.build and Device API currently do not work with CMake. * The known issues will be addressed in a future release. Decreased max CTA count from 32 to 16 on Blackwell * SM overhead is decreased by 50% with this improvement. * This may cause some perf drop on Blackwell because of the reduced SM usage. * If the extra SM capacity is not desired, two options are available to restore to previous behavior: 1) Setting NCCL_MIN_CTAS=32 NCCL_MAX_CTAS=32 environment variables; 2) setting communicator config to over-write max CTA count to 32. * Based on community feedback, future versions may consider different trade-offs between performance and SM overhead. Plugins * Network * App-aware Network plugin. NCCL passes information about communication operations to be executed on the network end point. This allows for better tuning of network end points and their use in the plugins. * Improve handling of physical and virtual network devices and load/unload. * Network plugin version 11 - add explicit context and communication ID support for per communicator init/finalize. * Add Multi-Request Net API. Using this will help NCCL to anticipate multiple send/recv requests and optimize for it. See maxMultiRequestSize field in ncclNetProperties_v11_t. * Profiler * Add support for API events (group, collective, and p2p) and for tracking kernel launches in the profiler plugin. * Add Inspector Profiler Plugin (see section above). * Add a hook to Google’s CoMMA profiler on github. * Tuner * Expose NCCL tuning constants at tuner initialization via ncclTunerConstants_v5_t. * Add NVL Domain Information API. * Support multiple plugin types from a single shared object. New Parameterization and ncclConfig changes: * Add new option NCCL_MNNVL_CLIQUE_ID=-2 which will use rack serial number to partition the MNNVL clique. This will limit NVLink domains to GPUs within a single rack. * Add NCCL_NETDEVS_POLICY to control how NET devices are assigned to GPUs. The default (AUTO) is the policy used in previous versions. * Add NCCL_SINGLE_PROC_MEM_REG_ENABLE control variable to enable NVLS UB registration in the “one process, multiple ranks” case as opt in. * Move nChannelsPerNetPeer into ncclConfig. NCCL_NCHANNELS_PER_NET_PEER can override the value in ncclConfig. * Enable PxN over C2C by default * PxN over C2C will improve performance for Grace-Blackwell platforms by allowing NCCL to leverage the NIC attached to a peer GPU over NVLINK, C2C, and PCIe. * This behavior can be overridden by setting NCCL_PXN_C2C=0. Other Improvements: * Allow FP8 support for non-reductive operations on pre sm90 devices. (See https://github.com/pytorch/pytorch/pull/151594#discussion_r2135777776) * Fix NVLS+CollNet and temporarily disables COLLNET_CHAIN for >8 GPUs. * Only consider running interfaces for socket traffic. NCCL will not attempt to use interfaces that do not have the IFF_RUNNING bit. (https://github.com/NVIDIA/nccl/issues/1798) * Modernize mutex management. Convert to std::mutex and std::lock_guard. * Remove sm35 and sm50 GENCODE targets which have long been deprecated and were causing issues with the latest NCCL release builds. * Improved NVLS/NVLSTree tuning prediction to improve algorithm and protocol selection. * NVLSTree Tuning Fixes. Update tuning data for H100, GB200-NV72. * Respond better to RoCE link flaps. Instead of reporting an “unknown event” it will now report “GID table changed”. * Move libvirt bridge interface to the end of possible interfaces so that they are considered last. These interfaces are usually virtual bridges to relay traffic to containers running on the host and cannot be used for traffic to a remote node and are therefore unsuitable. |
||
 Sylvain Jeaugey
|
178b6b7590 |
2.22.3-1
Rework core for NVIDIA Trusted Computing * Compress work structs so that they are shared between channels * Utilize the full amount of kernel argument space permitted (4k) before resorting to work fifo. * Rework the task preprocessing phase. * Use a separate abortDevFlag which is kept in sync with abortFlag using cudaMemcpy operations. * Rename src/include/align.h to src/include/bitops.h Add lazy connection establishment for collective operations * Move buffer allocation and connection establishment to the first collective operation using that algorithm. * Accelerate init time and reduce memory usage. * Avoid allocating NVLS buffers if all calls are registered. * Compute algo/proto in ncclLaunchCollTasksInfo early on. * Connect peers in ncclCollPreconnectFunc if not connected already. * Also move shared buffer creation to the first send/recv call. Accelerate intra-node NVLink detection * Make each rank only detect NVLinks attached to its GPU. * Fuse XMLs to reconstruct the full NVLink topology Add init profiling to report time spend in different init phases. * Report timings of bootstrap, allgather, search, connect, etc. * Add new "PROFILE" category for NCCL_DEBUG_SUBSYS. Add support for PCI p2p on split PCI switches * Detect split PCI switches through a kernel module exposing switch information. * Update the topology XML and graph to add those inter-switch connections. Add cost estimation API * Add a new ncclGroupEndSimulate primitive to return the estimated time a group would take. Net/IB: Add separate traffic class for fifo messages * Add NCCL_IB_FIFO_TC to control the traffic class of fifo messages independently from NCCL_IB_TC. Merges PR #1194 Net/IB: Add support for IB router * Use flid instead of lid if subnets do not match * Warn if flid is 0 Optimizations and fixes for device network offload (unpack) * Double the default number of channels * Cache netDeviceType * Fix save/increment head logic to enable Tree support. Support ncclGroupStart/End for ncclCommAbort/Destroy * Allow Abort/Destroy to be called within a group when managing multiple GPUs with a single process. Improve Tuner API * Provide to the plugin the original cost table so that the plugin can leave unknown or disabled algo/proto combinations untouched. * Remove nvlsSupport and collnetSupport. Do not print version to stdout when using a debug file * Also print version from all processes with INFO debug level. Fixes issue #1271 Fix clang warnings in NVTX headers * Update NVTX headers to the latest version Fixes issue #1270 Disable port fusion in heterogeneous systems * Do not fuse ports if a mix of multi-port and single port are detected. Fix NVLS graphs search for dual NICs. * Fix NVLS graph search when we have more than one NIC per GPU. Fix crash with collnetDirect * Add separate graph search for collnetDirect, testing alltoall paths and working similarly to the NVLS search. Fix hang when nodes have different CPU types * Add the CPU type to the rank peer info. * Align all ranks on the CPU type after the first allgather. * Only use the aligned CPU type for all tuning operations. Fixes issue #1136 Fixes issue #1184 Fix performance of registered send/recv operations * Allow for single full size operations * Add INFO to confirm the registration of send/recv buffers. Move all sync ops to finalize stage * Ensure ncclCommDestroy is non-blocking if ncclCommFinalize has been called. Improve error reporting during SHM segment creation Improve support of various compilers Merges PR #1177 Merges PR #1228 Allow net and tuner plugins to be statically linked * Search for ncclNet or ncclTuner symbols in the main binary. Merges PR #979 Plugin examples includes cleanup * Harmonize err.h and common.h usage. * Add mixed plugin with both net and tuner. |