sunrpc: Report per-RPC execution stats

Introduce a mechanism to report the server-side execution latency of
each RPC. The goal is to enable user space to filter the trace
record for latency outliers, build histograms, etc.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h
index 786ae2255f0566bc50b44368303a9daba049678c..3bd7504066e1ebfc25e105d3578b88b162f23ce2 100644 (file)
--- a/include/linux/sunrpc/svc.h
+++ b/include/linux/sunrpc/svc.h
@@ -283,6 +283,7 @@ struct svc_rqst {
        int                     rq_reserved;    /* space on socket outq
                                                 * reserved for this request
                                                 */
+       ktime_t                 rq_stime;       /* start time */
 
        struct cache_req        rq_chandle;     /* handle passed to caches for 
                                                 * request delaying 

diff --git a/include/trace/events/sunrpc.h b/include/trace/events/sunrpc.h
index 5a8157c0490045a159c1c679aa07205744d47231..1b383f71ccd743249d64b2f00fbff307616cec64 100644 (file)
--- a/include/trace/events/sunrpc.h
+++ b/include/trace/events/sunrpc.h
@@ -705,6 +705,27 @@ TRACE_EVENT(svc_handle_xprt,
                __entry->len, show_svc_xprt_flags(__entry->flags))
 );
 
+TRACE_EVENT(svc_stats_latency,
+       TP_PROTO(const struct svc_rqst *rqst),
+
+       TP_ARGS(rqst),
+
+       TP_STRUCT__entry(
+               __field(u32, xid)
+               __field(unsigned long, execute)
+               __string(addr, rqst->rq_xprt->xpt_remotebuf)
+       ),
+
+       TP_fast_assign(
+               __entry->xid = be32_to_cpu(rqst->rq_xid);
+               __entry->execute = ktime_to_us(ktime_sub(ktime_get(),
+                                                        rqst->rq_stime));
+               __assign_str(addr, rqst->rq_xprt->xpt_remotebuf);
+       ),
+
+       TP_printk("addr=%s xid=0x%08x execute-us=%lu",
+               __get_str(addr), __entry->xid, __entry->execute)
+);
 
 DECLARE_EVENT_CLASS(svc_deferred_event,
        TP_PROTO(struct svc_deferred_req *dr),

diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c
index f745754a55ea3c082ed52f8b4e4e1e4e50c36780..a7425da14f5b688a4dea5bb0a9a8445c51d6d940 100644 (file)
--- a/net/sunrpc/svc_xprt.c
+++ b/net/sunrpc/svc_xprt.c
@@ -782,7 +782,7 @@ static int svc_handle_xprt(struct svc_rqst *rqstp, struct svc_xprt *xprt)
                        len = svc_deferred_recv(rqstp);
                else
                        len = xprt->xpt_ops->xpo_recvfrom(rqstp);
-               dprintk("svc: got len=%d\n", len);
+               rqstp->rq_stime = ktime_get();
                rqstp->rq_reserved = serv->sv_max_mesg;
                atomic_add(rqstp->rq_reserved, &xprt->xpt_reserved);
        }
@@ -888,6 +888,7 @@ int svc_send(struct svc_rqst *rqstp)
 
        /* Grab mutex to serialize outgoing data. */
        mutex_lock(&xprt->xpt_mutex);
+       trace_svc_stats_latency(rqstp);
        if (test_bit(XPT_DEAD, &xprt->xpt_flags)
                        || test_bit(XPT_CLOSE, &xprt->xpt_flags))
                len = -ENOTCONN;