2.24.3-1

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

src/debug.cc

@@ -8,6 +8,7 @@
 #include "nccl_net.h"
 #include <stdlib.h>
 #include <stdarg.h>
+#include <stdio.h>
 #include <string.h>
 #include <strings.h>
 #include <sys/syscall.h>
@@ -89,6 +90,8 @@ static void ncclDebugInit() {
         mask = NCCL_REG;
       } else if (strcasecmp(subsys, "PROFILE") == 0) {
         mask = NCCL_PROFILE;
+      } else if (strcasecmp(subsys, "RAS") == 0) {
+        mask = NCCL_RAS;
       } else if (strcasecmp(subsys, "ALL") == 0) {
         mask = NCCL_ALL;
       }
@@ -224,6 +227,19 @@ void ncclDebugLog(ncclDebugLogLevel level, unsigned long flags, const char *file
   }
 }
 
+NCCL_API(void, ncclResetDebugInit);
+void ncclResetDebugInit() {
+  // Cleans up from a previous ncclDebugInit() and reruns.
+  // Use this after changing NCCL_DEBUG and related parameters in the environment.
+  __atomic_load_n(&ncclDebugLevel, __ATOMIC_ACQUIRE);
+  if (ncclDebugFile != stdout) {
+    fclose(ncclDebugFile);
+    ncclDebugFile = stdout;
+  }
+  ncclDebugLevel = -1;
+  ncclDebugInit();
+}
+
 NCCL_PARAM(SetThreadName, "SET_THREAD_NAME", 0);
 
 void ncclSetThreadName(pthread_t thread, const char *fmt, ...) {