SMB3: Track total time spent on roundtrips for each SMB3 command

Also track minimum and maximum time by command in /proc/fs/cifs/Stats
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/cifs/cifs_debug.c

@@ -462,8 +462,13 @@ static ssize_t cifs_stats_proc_write(struct file *file,
 			server = list_entry(tmp1, struct TCP_Server_Info,
 					    tcp_ses_list);
 #ifdef CONFIG_CIFS_STATS2
-			for (i = 0; i < NUMBER_OF_SMB2_COMMANDS; i++)
+			for (i = 0; i < NUMBER_OF_SMB2_COMMANDS; i++) {
+				atomic_set(&server->num_cmds[i], 0);
 				atomic_set(&server->smb2slowcmd[i], 0);
+				server->time_per_cmd[i] = 0;
+				server->slowest_cmd[i] = 0;
+				server->fastest_cmd[0] = 0;
+			}
 #endif /* CONFIG_CIFS_STATS2 */
 			list_for_each(tmp2, &server->smb_ses_list) {
 				ses = list_entry(tmp2, struct cifs_ses,
@@ -531,9 +536,19 @@ static int cifs_stats_proc_show(struct seq_file *m, void *v)
 		server = list_entry(tmp1, struct TCP_Server_Info,
 				    tcp_ses_list);
 #ifdef CONFIG_CIFS_STATS2
+		seq_puts(m, "\nTotal time spent processing by command. Time ");
+		seq_printf(m, "units are jiffies (%d per second)\n", HZ);
+		seq_puts(m, "  SMB3 CMD\tNumber\tTotal Time\tFastest\tSlowest\n");
+		seq_puts(m, "  --------\t------\t----------\t-------\t-------\n");
+		for (j = 0; j < NUMBER_OF_SMB2_COMMANDS; j++)
+			seq_printf(m, "  %d\t\t%d\t%llu\t\t%u\t%u\n", j,
+				atomic_read(&server->num_cmds[j]),
+				server->time_per_cmd[j],
+				server->fastest_cmd[j],
+				server->slowest_cmd[j]);
 		for (j = 0; j < NUMBER_OF_SMB2_COMMANDS; j++)
 			if (atomic_read(&server->smb2slowcmd[j]))
-				seq_printf(m, "%d slow responses from %s for command %d\n",
+				seq_printf(m, "  %d slow responses from %s for command %d\n",
 					atomic_read(&server->smb2slowcmd[j]),
 					server->hostname, j);
 #endif /* STATS2 */

fs/cifs/cifsglob.h

@@ -714,7 +714,11 @@ struct TCP_Server_Info {
 #ifdef CONFIG_CIFS_STATS2
 	atomic_t in_send; /* requests trying to send */
 	atomic_t num_waiters;   /* blocked waiting to get in sendrecv */
+	atomic_t num_cmds[NUMBER_OF_SMB2_COMMANDS]; /* total requests by cmd */
 	atomic_t smb2slowcmd[NUMBER_OF_SMB2_COMMANDS]; /* count resps > 1 sec */
+	__u64 time_per_cmd[NUMBER_OF_SMB2_COMMANDS]; /* total time per cmd */
+	__u32 slowest_cmd[NUMBER_OF_SMB2_COMMANDS];
+	__u32 fastest_cmd[NUMBER_OF_SMB2_COMMANDS];
 #endif /* STATS2 */
 	unsigned int	max_read;
 	unsigned int	max_write;

fs/cifs/transport.c

@@ -104,7 +104,10 @@ DeleteMidQEntry(struct mid_q_entry *midEntry)
 {
 #ifdef CONFIG_CIFS_STATS2
 	__le16 command = midEntry->server->vals->lock_cmd;
+	__u16 smb_cmd = le16_to_cpu(midEntry->command);
 	unsigned long now;
+	unsigned long roundtrip_time;
+	struct TCP_Server_Info *server = midEntry->server;
 #endif
 	midEntry->mid_state = MID_FREE;
 	atomic_dec(&midCount);
@@ -114,6 +117,23 @@ DeleteMidQEntry(struct mid_q_entry *midEntry)
 		cifs_small_buf_release(midEntry->resp_buf);
 #ifdef CONFIG_CIFS_STATS2
 	now = jiffies;
+	if (now < midEntry->when_alloc)
+		cifs_dbg(VFS, "invalid mid allocation time\n");
+	roundtrip_time = now - midEntry->when_alloc;
+
+	if (smb_cmd < NUMBER_OF_SMB2_COMMANDS) {
+		if (atomic_read(&server->num_cmds[smb_cmd]) == 0) {
+			server->slowest_cmd[smb_cmd] = roundtrip_time;
+			server->fastest_cmd[smb_cmd] = roundtrip_time;
+		} else {
+			if (server->slowest_cmd[smb_cmd] < roundtrip_time)
+				server->slowest_cmd[smb_cmd] = roundtrip_time;
+			else if (server->fastest_cmd[smb_cmd] > roundtrip_time)
+				server->fastest_cmd[smb_cmd] = roundtrip_time;
+		}
+		cifs_stats_inc(&server->num_cmds[smb_cmd]);
+		server->time_per_cmd[smb_cmd] += roundtrip_time;
+	}
 	/*
 	 * commands taking longer than one second (default) can be indications
 	 * that something is wrong, unless it is quite a slow link or a very
@@ -131,11 +151,10 @@ DeleteMidQEntry(struct mid_q_entry *midEntry)
 		 * smb2slowcmd[NUMBER_OF_SMB2_COMMANDS] counts by command
 		 * NB: le16_to_cpu returns unsigned so can not be negative below
 		 */
-		if (le16_to_cpu(midEntry->command) < NUMBER_OF_SMB2_COMMANDS)
-			cifs_stats_inc(&midEntry->server->smb2slowcmd[le16_to_cpu(midEntry->command)]);
+		if (smb_cmd < NUMBER_OF_SMB2_COMMANDS)
+			cifs_stats_inc(&server->smb2slowcmd[smb_cmd]);
 
-		trace_smb3_slow_rsp(le16_to_cpu(midEntry->command),
-			       midEntry->mid, midEntry->pid,
+		trace_smb3_slow_rsp(smb_cmd, midEntry->mid, midEntry->pid,
 			       midEntry->when_sent, midEntry->when_received);
 		if (cifsFYI & CIFS_TIMER) {
 			pr_debug(" CIFS slow rsp: cmd %d mid %llu",