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@xxxxxxxxxx>
---
include/linux/sunrpc/svc.h | 1 +
include/trace/events/sunrpc.h | 21 +++++++++++++++++++++
net/sunrpc/svc_xprt.c | 3 ++-
3 files changed, 24 insertions(+), 1 deletion(-)
diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h
index 786ae22..3bd7504 100644
--- 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 5a8157c..1b383f7 100644
--- a/include/trace/events/sunrpc.h
+++ b/include/trace/events/sunrpc.h
@@ -705,6 +705,27 @@
__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 f745754..a7425da 100644
--- 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;
--
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