Introduce a low-overhead mechanism to report information about
latencies of individual RPCs. The goal is to enable user space to
filter the trace record for latency outliers, or build histograms,
etc.
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
---
include/trace/events/sunrpc.h | 45 +++++++++++++++++++++++++++++++++++++++++
net/sunrpc/stats.c | 16 ++++++++++-----
2 files changed, 56 insertions(+), 5 deletions(-)
diff --git a/include/trace/events/sunrpc.h b/include/trace/events/sunrpc.h
index 53bbaea..fda9e72 100644
--- a/include/trace/events/sunrpc.h
+++ b/include/trace/events/sunrpc.h
@@ -212,6 +212,51 @@
);
+TRACE_EVENT(rpc_stats_latency,
+
+ TP_PROTO(
+ const struct rpc_task *task,
+ ktime_t backlog,
+ ktime_t rtt,
+ ktime_t execute
+ ),
+
+ TP_ARGS(task, backlog, rtt, execute),
+
+ TP_STRUCT__entry(
+ __field(u32, xid)
+ __field(int, version)
+ __string(progname, task->tk_client->cl_program->name)
+ __string(procname, rpc_proc_name(task))
+ __field(unsigned long, backlog)
+ __field(unsigned long, rtt)
+ __field(unsigned long, execute)
+ __string(addr,
+ task->tk_xprt->address_strings[RPC_DISPLAY_ADDR])
+ __string(port,
+ task->tk_xprt->address_strings[RPC_DISPLAY_PORT])
+ ),
+
+ TP_fast_assign(
+ __entry->xid = be32_to_cpu(task->tk_rqstp->rq_xid);
+ __entry->version = task->tk_client->cl_vers;
+ __assign_str(progname, task->tk_client->cl_program->name)
+ __assign_str(procname, rpc_proc_name(task))
+ __entry->backlog = ktime_to_us(backlog);
+ __entry->rtt = ktime_to_us(rtt);
+ __entry->execute = ktime_to_us(execute);
+ __assign_str(addr,
+ task->tk_xprt->address_strings[RPC_DISPLAY_ADDR]);
+ __assign_str(port,
+ task->tk_xprt->address_strings[RPC_DISPLAY_PORT]);
+ ),
+
+ TP_printk("peer=[%s]:%s xid=0x%08x %sv%d %s backlog=%lu rtt=%lu execute=%lu",
+ __get_str(addr), __get_str(port), __entry->xid,
+ __get_str(progname), __entry->version, __get_str(procname),
+ __entry->backlog, __entry->rtt, __entry->execute)
+);
+
/*
* First define the enums in the below macros to be exported to userspace
* via TRACE_DEFINE_ENUM().
diff --git a/net/sunrpc/stats.c b/net/sunrpc/stats.c
index 1e67133..f68aa46 100644
--- a/net/sunrpc/stats.c
+++ b/net/sunrpc/stats.c
@@ -24,6 +24,8 @@
#include <linux/sunrpc/metrics.h>
#include <linux/rcupdate.h>
+#include <trace/events/sunrpc.h>
+
#include "netns.h"
#define RPCDBG_FACILITY RPCDBG_MISC
@@ -148,7 +150,7 @@ void rpc_count_iostats_metrics(const struct rpc_task *task,
struct rpc_iostats *op_metrics)
{
struct rpc_rqst *req = task->tk_rqstp;
- ktime_t delta, now;
+ ktime_t backlog, execute, now;
if (!op_metrics || !req)
return;
@@ -164,16 +166,20 @@ void rpc_count_iostats_metrics(const struct rpc_task *task,
op_metrics->om_bytes_sent += req->rq_xmit_bytes_sent;
op_metrics->om_bytes_recv += req->rq_reply_bytes_recvd;
+ backlog = 0;
if (ktime_to_ns(req->rq_xtime)) {
- delta = ktime_sub(req->rq_xtime, task->tk_start);
- op_metrics->om_queue = ktime_add(op_metrics->om_queue, delta);
+ backlog = ktime_sub(req->rq_xtime, task->tk_start);
+ op_metrics->om_queue = ktime_add(op_metrics->om_queue, backlog);
}
+
op_metrics->om_rtt = ktime_add(op_metrics->om_rtt, req->rq_rtt);
- delta = ktime_sub(now, task->tk_start);
- op_metrics->om_execute = ktime_add(op_metrics->om_execute, delta);
+ execute = ktime_sub(now, task->tk_start);
+ op_metrics->om_execute = ktime_add(op_metrics->om_execute, execute);
spin_unlock(&op_metrics->om_lock);
+
+ trace_rpc_stats_latency(req->rq_task, backlog, req->rq_rtt, execute);
}
EXPORT_SYMBOL_GPL(rpc_count_iostats_metrics);
--
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