Sylvain Jeaugey
60240fec77
Add scalable init API
* Add new ncclCommInitRankScalable to allow for passing multiple
unique IDs to the init function.
* Spreads the load onto multiple bootstrap roots, allowing for
constant bootstrap time.
* Requires multiple ranks to create a unique ID, and the CPU-side
ID exchange code to call allgather[v] instead of broadcast.
Accelerate init bootstrap operations
* Reduce the number of calls to allgather.
* Allow roots to reply early to ranks when information is already
available.
* Add an option to use ncclNet instead of sockets to perform
bootstrap allgather operations.
Add PAT algorithms for Allgather and ReduceScatter
* Parallel Aggregated Trees, variation of Bruck algorithm.
* Logarithmic number of network steps for small sizes at scale.
* Only supports one rank per node at the moment.
Add support for registered buffers for intra-node communication.
* Allow registered user buffers to be accessed directly intra-node
* Avoids extra copies in algorithms which permit it, saving
memory bandwidth and helping with compute overlap.
Add profiler plugin API
* New plugin API for profiling
* Supports various levels of profiling, with a hierarchy.
Asynchronous graph allocation
* Make calls to cudaMalloc and cudaMemcpy during graph allocation
asynchronous.
* Significantly speeds up graph capture.
Use fatal IB asynchronous events to stop network operation
* Avoids many other error messages
* Only fatal errors are affected; potentially transient errors
(e.g. port down) do not cause an immediate stop.
Set P2P level to PXB on AMD CPUs when using more than 2 GPUs per node
* P2P would cause a significant performance degradation when using
many GPUs, and therefore many interleaved data flows.
* Disable P2P through the CPU when we have 3+ GPUs per node; keep it
enabled when we only have 2 GPUs.
Improve the init logs to report the real NCCL function.
* Make the log report ncclCommInitRank or ncclCommSplit, rather than
the generic ncclCommInitRankFunc.
Add a parameter to set the location of the user configuration file.
* Add NCCL_CONF_FILE environment variable to set where the user's
configuration file resides.
Increase default IB timeout
* Increase IB timeout value from 18 to 20.
* Should help avoid fatal errors on large RoCE systems.
Add new check for nvidia peermem
* On linux kernels 6.6+, /sys/kernel/mm/memory_peers is no longer
present; check for /sys/module/nvidia_peermem/version instead.
Fix old performance regression when mixing small and large operations.
* Improves distribution of work on channels.
Fix crash when NUMA IDs are equal to -1.
* Can happen when a NIC is a virtual NIC, or when linux doesn't
know which NUMA node a device is attached to
* Issue NVIDIA/nccl-tests#233
Fix tree graph search when NCCL_CROSS_NIC is set to 1.
* Would force NCCL to use the balanced_tree pattern, thereby
disabling LL128 on platforms with 1 GPU+1 NIC per PCI switch.
* Would also try to use alternate rings even though it was not
needed.
Compiler tweaks and fixes
* PR #1177
* PR #1228
Fix stack smash
* PR #1325
Fixes for multi-node NVLink + IB operation
Coverity fixes and comments.
[ROCm/rccl commit: 68b542363f]
64 rindas
2.2 KiB
C++
64 rindas
2.2 KiB
C++
/*************************************************************************
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* Copyright (c) 2016-2019, NVIDIA CORPORATION. All rights reserved.
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*
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* See LICENSE.txt for license information
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************************************************************************/
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#include "core.h"
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void dumpLine(int* values, int nranks, const char* prefix) {
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constexpr int line_length = 128;
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char line[line_length];
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int num_width = snprintf(nullptr, 0, "%d", nranks-1); // safe as per "man snprintf"
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int n = snprintf(line, line_length, "%s", prefix);
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for (int i = 0; i < nranks && n < line_length-1; i++) {
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n += snprintf(line + n, line_length - n, " %*d", num_width, values[i]);
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// At this point n may be more than line_length-1, so don't use it
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// for indexing into "line".
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}
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if (n >= line_length) {
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// Sprintf wanted to write more than would fit in the buffer. Assume
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// line_length is at least 4 and replace the end with "..." to
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// indicate that it was truncated.
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snprintf(line+line_length-4, 4, "...");
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}
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INFO(NCCL_INIT, "%s", line);
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}
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ncclResult_t ncclBuildRings(int nrings, int* rings, int rank, int nranks, int* prev, int* next) {
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for (int r=0; r<nrings; r++) {
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char prefix[40];
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/*sprintf(prefix, "[%d] Channel %d Prev : ", rank, r);
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dumpLine(prev+r*nranks, nranks, prefix);
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sprintf(prefix, "[%d] Channel %d Next : ", rank, r);
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dumpLine(next+r*nranks, nranks, prefix);*/
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int current = rank;
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for (int i=0; i<nranks; i++) {
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rings[r*nranks+i] = current;
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current = next[r*nranks+current];
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}
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snprintf(prefix, sizeof(prefix), "Channel %02d/%02d :", r, nrings);
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if (rank == 0) dumpLine(rings+r*nranks, nranks, prefix);
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if (current != rank) {
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WARN("Error : ring %d does not loop back to start (%d != %d)", r, current, rank);
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return ncclInternalError;
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}
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// Check that all ranks are there
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for (int i=0; i<nranks; i++) {
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int found = 0;
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for (int j=0; j<nranks; j++) {
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if (rings[r*nranks+j] == i) {
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found = 1;
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break;
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}
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}
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if (found == 0) {
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WARN("Error : ring %d does not contain rank %d", r, i);
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return ncclInternalError;
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}
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}
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}
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return ncclSuccess;
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}
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