Sylvain Jeaugey
c4e2aa6c79
Add support for improved fault tolerance: non-blocking mode, new init function with config, and ncclCommFinalize function. Reintroduce collnet+chain algorithm, alongside collnet+direct. Add LL protocol for intra-node P2P (on by default) and network communication (off by default). Use network instead of shared memory when performance is better. Fix: wait for CUDA graph destroy before destroying comm with linked graph resources. Remove aggressive polling during enqueue. Fix DMABUF fallback on MOFED 5.4 and earlier.
94 lines
2.9 KiB
C++
94 lines
2.9 KiB
C++
/*************************************************************************
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* Copyright (c) 2016-2022, 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 "shm.h"
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#include "checks.h"
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#include <sys/types.h>
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#include <sys/mman.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <errno.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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// Change functions behavior to match other SYS functions
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static int shm_allocate(int fd, const int shmSize) {
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int err = posix_fallocate(fd, 0, shmSize);
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if (err) { errno = err; return -1; }
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return 0;
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}
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static int shm_map(int fd, const int shmSize, void** ptr) {
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*ptr = mmap(NULL, shmSize, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
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return (*ptr == MAP_FAILED) ? -1 : 0;
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}
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static ncclResult_t ncclShmSetup(char* shmPath, const int shmSize, int* fd, void** ptr, int create) {
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if (create) {
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if (shmPath[0] == '\0') {
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sprintf(shmPath, "/dev/shm/nccl-XXXXXX");
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*fd = mkstemp(shmPath);
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} else {
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SYSCHECKVAL(open(shmPath, O_CREAT | O_RDWR, S_IRUSR | S_IWUSR), "open", *fd);
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}
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if (ftruncate(*fd, shmSize) != 0) {
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WARN("Error: failed to extend %s to %d bytes", shmPath, shmSize);
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return ncclSystemError;
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}
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INFO(NCCL_ALLOC, "Allocated %d bytes of shared memory in %s\n", shmSize, shmPath);
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} else {
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SYSCHECKVAL(open(shmPath, O_RDWR, S_IRUSR | S_IWUSR), "open", *fd);
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}
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*ptr = (char*)mmap(NULL, shmSize, PROT_READ|PROT_WRITE, MAP_SHARED, *fd, 0);
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if (*ptr == NULL) {
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WARN("Could not map %s\n", shmPath);
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return ncclSystemError;
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}
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close(*fd);
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*fd = -1;
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if (create) memset(*ptr, 0, shmSize);
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return ncclSuccess;
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}
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ncclResult_t ncclShmOpen(char* shmPath, const int shmSize, void** shmPtr, void** devShmPtr, int create) {
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int fd = -1;
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void* ptr = MAP_FAILED;
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ncclResult_t res = ncclSuccess;
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NCCLCHECKGOTO(ncclShmSetup(shmPath, shmSize, &fd, &ptr, create), res, sysError);
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if (devShmPtr) {
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CUDACHECKGOTO(cudaHostRegister(ptr, shmSize, cudaHostRegisterMapped), res, cudaError);
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CUDACHECKGOTO(cudaHostGetDevicePointer(devShmPtr, ptr, 0), res, cudaError);
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}
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*shmPtr = ptr;
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return ncclSuccess;
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sysError:
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WARN("Error while %s shared memory segment %s (size %d)", create ? "creating" : "attaching to", shmPath, shmSize);
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cudaError:
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if (fd != -1) close(fd);
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if (create) shm_unlink(shmPath);
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if (ptr != MAP_FAILED) munmap(ptr, shmSize);
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*shmPtr = NULL;
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return res;
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}
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ncclResult_t ncclShmUnlink(const char* shmPath) {
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if (shmPath != NULL) SYSCHECK(unlink(shmPath), "unlink");
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return ncclSuccess;
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}
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ncclResult_t ncclShmClose(void* shmPtr, void* devShmPtr, const int shmSize) {
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if (shmPtr) {
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if (devShmPtr) CUDACHECK(cudaHostUnregister(shmPtr));
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if (munmap(shmPtr, shmSize) != 0) {
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WARN("munmap of shared memory failed");
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return ncclSystemError;
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}
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}
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return ncclSuccess;
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}
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