858b4e76eb3fa210704aa95514f48b8b0f2013bc
7 次程式碼提交
| 作者 | SHA1 | 備註 | 日期 | |
|---|---|---|---|---|
 Marzieh Berenjkoub
|
858b4e76eb | Merge remote-tracking branch 'nccl/master' into develop | ||
 Arm Patinyasakdikul
|
84fdcab68a | Added copyrights for Palamida scan 7.2. (#2018) | ||
 BertanDogancay
|
3f94267f21 | Merge remote-tracking branch 'nccl/master' into develop | ||
 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. |
||
|
BertanDogancay
|
08a7be231b | Merge remote-tracking branch 'nccl/master' into develop | ||
 Kamil Iskra
|
3ea7eedf3b |
NCCL 2.27.5-1
Improvements for GB200 systems * Optimize the network performance by alternating the direction of the rings and the NIC to GPU assignment across communicators to limit unnecessary sharing. * Fix the detection of C2C links in case GPU Direct RDMA is disabled between a GPU and a NIC. * Fix PXN support on MNNVL systems, where NCCL would try (and fail) to share regular host memory across multiple nodes. * Fix P2C (PXN over C2C), which is now preferred over regular PXN. This support is currently preliminary and is disabled by default; use NCCL_PXN_C2C=1 to enable. Further reduce the overheads of CUDA graph capturing, which increased in NCCL 2.26.2 for large graphs. Optimize the network performance on DGX B200 systems by adjusting the bandwidths provided to the graph search algorithm. Enable fp8 reductions in symmetric kernels on Blackwell with CUDA 12.8. Restore the plugin name handling logic to make it possible to specify a path to the plugin (Issue #1732). Restore the ability to change NCCL_COLLNET_ENABLE during execution (Issue #1741). Add an example tuner plugin with CSV-based overrides. Remove an x86 dependency from the example profiler. |
||
|
Kamil Iskra
|
72d2432094 |
NCCL 2.27.3-1
Symmetric memory API and symmetric kernels * Redesign from the ground up, enabling major latency and bandwidth improvements. * Add new API calls to register user-allocated memory among communicator ranks into a NCCL window: ncclCommWindowRegister() and ncclCommWindowDeregister(). The calls currently support symmetric registration for P2P and NVLS, and require VMM memory buffers (i.e., CUMEM must be operational). * Implement specialized kernels taking advantage of symmetrically registered memory, with performance gains expected particularly for small to medium message sizes. * The kernels support 32 bit floating point types and smaller, and sum as the reduction operator, with no more than one collective operation per group. * Floating point summation is always done in fp32 accumulators (with the exception of fp8 on NVLS, where it uses fp16 inside the switch). Thus, the accuracy with fp8 and fp16 data types should be much improved. * This initial implementation supports non-network communicators only (P2P and NVLS transports). * To explore this functionality users need to use the new memory registration API calls with the NCCL_WIN_COLL_SYMMETRIC flag and all ranks of a communicator must pass buffers at the same offset in the same registration when invoking a collective NCCL operation. Add support for DGX Spark. Add support for DirectNIC (CX8) to the internal IB plugin. Add a new ncclCommShrink() API call * It is a non-collective call similar to ncclCommSplit(), which makes it possible to exclude some (possibly unresponsive) ranks from the parent communicator. Add support for loading multiple network plugins * This enables the creation of generic containers that can work across a range of providers. * Allow NCCL_NET_PLUGIN to accept a comma-separated list of plugins to load. NVLink SHARP (NVLS) improvements * Implement NVLS+IB SHARP support for AllGather and ReduceScatter with user buffer registration. This improves performance and reduces the number of CTAs needed to achieve peak bandwidth. * Gracefully fall back by default to other transports if NVLS initialization fails (the old behavior of returning an error code from a NCCL call can be preserved by setting NCCL_NVLS_ENABLE=1). * Decrease the NVLS channel count to 24 on Blackwell systems with multiple NVLink domains per communicator. * Enable fine-tuning of NCCL behavior per communicator using new "ncclConfig_t" members "collnetEnable", "CTAPolicy", and "nvlsCTAs". Profiler improvements * Extend the init function by adding communicator name, comm id (hash), rank, number of ranks, number of nodes, and the NCCL log function to the argument list. This makes the name and the comm id available to all events in the communicator without explicitly passing them to each individual event. Add the communicator id and rank to the profiler trace filename. Now, the communicator name can be set via a new "ncclConfig_t" member "commName". * Improve the accuracy of the GPU kernel events by providing GPU-generated timestamps for the start and stop of every NCCL operation. * Harmonize proxy events, removing overlaps between ProxyOp and ProxyStep states. * Add support for network-defined event updates (through "recordEventState"). * Report the correct number of channels used by every collective/p2p operation (used to be set to nMaxChannels for collectives and absent for p2ps). * Fix the logic on proxyCtrl Idle/Active events (Issue #1162). * Fix an issue where the network proxy profiler could lose track of an event identifier (Issue #1682). * Improve the backward compatibility with plugins older than v4. * Ensure that the work counters are 0-initialized. * Fix a potential race condition in the network profiler that could result in an event being linked to a wrong parent. MNNVL improvements * Increase to 16 the number of NICs used to communicate between MNNVL domains on GB200 systems, to optimize the performance of collective operations. * Add support for more complex MNNVL topologies with up to 32 NICs per node. * If the MNNVL fabric initialization was unsuccessful, NCCL will now fail by default, so as to avoid inadvertently falling back to a potentially much slower network transport. Such failures are typically due to a misconfigured IMEX support on the system. To continue without MNNVL, restart the job with NCCL_MNNVL_ENABLE=0. * Fix a potential hang in alltoall-like communication patterns at a scale of over 80 ranks. * Make NCCL_P2P_DISABLE=1 imply NCCL_MNNVL_ENABLE=0 (so the latter no longer needs to be specified on MNNVL systems). * Fix an initialization failure when NCCL_TOPO_FILE is used on MNNVL systems. * Fix the graph search to exclude non-local NICs. * Fix the SHM transport to use fabric handles on MNNVL systems. NIC Fusion improvements * Disable the creation of fused NICs for physical devices that haven't been merged. * Flatten multiple ports to a single PCI device within the internal IB plugin and reparent dual-port NICs under the first PCI parent. If the parent is not a PCI switch, PCI devices for fused NICs won't be duplicated. * Route traffic on GB200-CX8 systems through DirectNIC, not the host interface. Improve support for platforms with C2C connectivity (e.g., GB200) * Enable GPUDirect RDMA for the NICs by default. * Add support for P2C (PXN over C2C) and the LL128 protocol. Extend NCCL fault tolerance in multithreaded scenarios * Support the creation of multiple nonblocking communicators within a single group and polling in parallel for the completion using multiple threads (one per communicator). Enable ncclImplicitOrderLaunch for CUDA 12.9+ * This can potentially speed up NCCL_IMPLICIT_LAUNCH_ORDER. Improve the netSocket transport latency and control * Provide finer control over the size of the socket send/receive buffers, the task size, and the number of sockets that a single peer can open. * Add support for the inlining of small messages behind the header when using multiple sockets per connection. Improve the readability of the CPU affinity in the debug output * Print it as a range string rather than a bitmask. Fix a potential race condition in graph execution * A contention could arise when mixing graph and non-graph execution. Improve PXN connection code * Avoid duplicate and unused connections. RAS fixes * Fix a memory corruption at job termination time in case of a previously failed initialization of a RAS socket connection. * Fix a race condition leading to a crash when generating a RAS report during communicator initialization (Issues #1669, #1718). * Fix a potential race condition when gathering data for a RAS status report. Fix a potential memory corruption in ncclCommSplit() * Memory could get corrupted when resource sharing was in use and the size of the NVLink domain in the new communicator was smaller than in the old one. Fix asynchronous graph upload * Fix a small memory leak. * Fix oversychronization. Add a check for out-of-memory conditions in ncclMemAlloc() Clean up the NCCL socket code * accept() will retry also if just reading the magic failed (Issue #1613). * connect() will retry also if poll() did not return a POLLOUT event (Issue #1618). * Add error checking in a few instances (Issue #1539). * Fix the loop condition in ncclFindInterfaceMatchSubnet() (Issue #1574). * Clean up the debug output, downgrading WARN messages to INFO in non-critical cases, and printing the peer's address where relevant. Switch NCCL_DEBUG_FILE to line buffering * This should help avoid mixed-up partial output lines in multithreaded cases. Other minor fixes * Improve the checks for buffer overflows in the graph code (Issue #1585). * Extend logging and state clearing to all four events in the internal IB plugin (Issue #1650). * Fix the error path in case IB communication is not ready (Issue #1489). * Add ECE logging for IB fabric. * Fix various minor issues in the graph module (Issue #1635). * Clean up the debug output in the graph code, downgrading WARN messages to INFO in non-critical cases. * Add a missing argument to a directSend() call (Issue #1628). * Remove duplicate code in sendProxySetup() (Issue #1420). * Fix the order of arguments of cudaDeviceCanAccessPeer() (Issue #1507). * Fix compiler warnings with GCC 14. * Fix a typo in a comment (Issue #1236). |