Add a comment to shutdown() in ncclSocketClose

[ROCm/rccl commit: 006b6bc7dc]
2023-04-13 09:00:59 -07:00
parent e35b05a872
commit 5eba5f178d
1 changed files with 4 additions and 0 deletions
@@ -819,6 +819,10 @@ ncclResult_t ncclSocketTryRecv(struct ncclSocket* sock, void* ptr, int size, int
 ncclResult_t ncclSocketClose(struct ncclSocket* sock) {
  if (sock != NULL) {
    if (sock->fd >= 0) {
+      /* shutdown() is needed to send FIN packet to proxy thread; shutdown() is not affected
+       * by refcount of fd, but close() is. close() won't close a fd and send FIN packet if
+       * the fd is duplicated (e.g. fork()). So shutdown() guarantees the correct and graceful
+       * connection close here. */
      shutdown(sock->fd, SHUT_RDWR);
      close(sock->fd);
    }