You can use the smbstat command to show statistical information about the smbd server. By default, the smbstat command shows general information about the CIFS service as well as dispatched CIFS request counters. For more information, see the smbstat(1M) man page.
The kstat command can be used to report on kernel CIFS statistics on a periodic basis and also to specify information about individual CIFS statistics. For more information, see the kstat(1M) man page.