control/server.py: auto detection of spdk reactor cpu bitmask

Signed-off-by: Alexander Indenbaum <aindenba@redhat.com>

ceph-nvmeof.conf

@@ -66,7 +66,7 @@ tgt_path = /usr/local/bin/nvmf_tgt
 timeout = 60.0
 #log_level = WARNING
 
-# Example value: -m 0x3 -L all
+# Example value: -L all
 # tgt_cmd_extra_args =
 
 # transports = tcp

control/server.py

@@ -54,6 +54,10 @@ def sigchld_handler(signum, frame):
     # GW process should exit now
     raise SystemExit(f"Gateway subprocess terminated {pid=} {exit_code=}")
 
+def int_to_bitmask(n):
+    """Converts an integer n to a bitmask string"""
+    return f"0x{hex((1 << n) - 1)[2:].upper()}"
+
 class GatewayServer:
     """Runs SPDK and receives client requests for the gateway service.
 
@@ -363,8 +367,17 @@ def _start_spdk(self, omap_state):
         spdk_tgt_cmd_extra_args = self.config.get_with_default(
             "spdk", "tgt_cmd_extra_args", "")
         cmd = [spdk_tgt_path, "-u", "-r", self.spdk_rpc_socket_path]
+
+        # Add extra args from the conf file
         if spdk_tgt_cmd_extra_args:
+            if '-m ' not in spdk_tgt_cmd_extra_args and '--cpumask ' not in spdk_tgt_cmd_extra_args:
+                # if not provided in configuration,
+                # calculate cpu mask available for spdk reactors
+                cpu_mask = f"-m {int_to_bitmask(os.cpu_count())}"
+                self.logger.info(f"SPDK autodetecting cpu_mask: {cpu_mask}")
+                cmd += shlex.split(cpu_mask)
             cmd += shlex.split(spdk_tgt_cmd_extra_args)
+
         self.logger.info(f"Starting {' '.join(cmd)}")
         try:
             # start spdk process