SUNRPC: introduce per-task RPC iostats

Account for various things that occur while an RPC task is executed.
Separate timers for RPC round trip and RPC execution time show how
long RPC requests wait in queue before being sent.  Eventually these
will be accumulated at xprt_release time in one place where they can
be viewed from userland.

Test plan:
Compile kernel with CONFIG_NFS enabled.

Signed-off-by: Chuck Lever <cel@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

5 files changed, 14 insertions, 0 deletions

diff --git a/include/linux/sunrpc/sched.h b/include/linux/sunrpc/sched.h
index 6c23f73a799a..45a64ae963ee 100644
--- a/include/linux/sunrpc/sched.h
+++ b/include/linux/sunrpc/sched.h
@@ -86,6 +86,12 @@ struct rpc_task {
                 struct work_struct      tk_work;        /* Async task work queue */
                 struct rpc_wait         tk_wait;        /* RPC wait */
         } u;
+
+        unsigned short          tk_timeouts;    /* maj timeouts */
+        size_t                  tk_bytes_sent;  /* total bytes sent */
+        unsigned long           tk_start;       /* RPC task init timestamp */
+        long                    tk_rtt;         /* round-trip time (jiffies) */
+
 #ifdef RPC_DEBUG
         unsigned short          tk_pid;         /* debugging aid */
 #endif
diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index cad7efe2cb22..84eb5b4565fc 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -996,6 +996,8 @@ call_timeout(struct rpc_task *task)
         }
 
         dprintk("RPC: %4d call_timeout (major)\n", task->tk_pid);
+        task->tk_timeouts++;
+
         if (RPC_IS_SOFT(task)) {
                 printk(KERN_NOTICE "%s: server %s not responding, timed out\n",
                                 clnt->cl_protname, clnt->cl_server);
diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c
index aa0449dcd8e5..cd51b5468332 100644
--- a/net/sunrpc/sched.c
+++ b/net/sunrpc/sched.c
@@ -817,6 +817,9 @@ void rpc_init_task(struct rpc_task *task, struct rpc_clnt *clnt, int flags, cons
 
         BUG_ON(task->tk_ops == NULL);
 
+        /* starting timestamp */
+        task->tk_start = jiffies;
+
         dprintk("RPC: %4d new task procpid %d\n", task->tk_pid,
                                 current->pid);
 }
diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
index 93a0a3ca0d5f..c6241976a6ee 100644
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -648,6 +648,8 @@ void xprt_complete_rqst(struct rpc_task *task, int copied)
                         task->tk_pid, ntohl(req->rq_xid), copied);
 
         task->tk_xprt->stat.recvs++;
+        task->tk_rtt = (long)jiffies - req->rq_xtime;
+
         list_del_init(&req->rq_list);
         req->rq_received = req->rq_private_buf.len = copied;
         rpc_wake_up_task(task);
diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index 6766b7f1ecf9..4b4e7dfdff14 100644
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -382,6 +382,7 @@ static int xs_tcp_send_request(struct rpc_task *task)
                 /* If we've sent the entire packet, immediately
                  * reset the count of bytes sent. */
                 req->rq_bytes_sent += status;
+                task->tk_bytes_sent += status;
                 if (likely(req->rq_bytes_sent >= req->rq_slen)) {
                         req->rq_bytes_sent = 0;
                         return 0;