/*
* linux/include/linux/sunrpc/metrics.h
*
* Declarations for RPC client per-operation metrics
*
* Copyright (C) 2005 Chuck Lever <[email protected]>
*
* RPC client per-operation statistics provide latency and retry
* information about each type of RPC procedure in a given RPC program.
* These statistics are not for detailed problem diagnosis, but simply
* to indicate whether the problem is local or remote.
*
* These counters are not meant to be human-readable, but are meant to be
* integrated into system monitoring tools such as "sar" and "iostat". As
* such, the counters are sampled by the tools over time, and are never
* zeroed after a file system is mounted. Moving averages can be computed
* by the tools by taking the difference between two instantaneous samples
* and dividing that by the time between the samples.
*
* The counters are maintained in a single array per RPC client, indexed
* by procedure number. There is no need to maintain separate counter
* arrays per-CPU because these counters are always modified behind locks.
*/

#ifndef _LINUX_SUNRPC_METRICS_H
#define _LINUX_SUNRPC_METRICS_H

#include <linux/seq_file.h>
#include <linux/ktime.h>

#define RPC_IOSTATS_VERS "1.0"

struct rpc_iostats {
/*
* These counters give an idea about how many request
* transmissions are required, on average, to complete that
* particular procedure. Some procedures may require more
* than one transmission because the server is unresponsive,
* the client is retransmitting too aggressively, or the
* requests are large and the network is congested.
*/
unsigned long om_ops, /* count of operations */
om_ntrans, /* count of RPC transmissions */
om_timeouts; /* count of major timeouts */

/*
* These count how many bytes are sent and received for a
* given RPC procedure type. This indicates how much load a
* particular procedure is putting on the network. These
* counts include the RPC and ULP headers, and the request
* payload.
*/
unsigned long long om_bytes_sent, /* count of bytes out */
om_bytes_recv; /* count of bytes in */

/*
* The length of time an RPC request waits in queue before
* transmission, the network + server latency of the request,
* and the total time the request spent from init to release
* are measured.
*/
ktime_t om_queue, /* queued for xmit */
om_rtt, /* RPC RTT */
om_execute; /* RPC execution */
} ____cacheline_aligned;

struct rpc_task;
struct rpc_clnt;

/*
* EXPORTed functions for managing rpc_iostats structures
*/

#ifdef CONFIG_PROC_FS

struct rpc_iostats * rpc_alloc_iostats(struct rpc_clnt *);
void rpc_count_iostats(const struct rpc_task *,
struct rpc_iostats *);
void rpc_print_iostats(struct seq_file *, struct rpc_clnt *);
void rpc_free_iostats(struct rpc_iostats *);

#else /* CONFIG_PROC_FS */

static inline struct rpc_iostats *rpc_alloc_iostats(struct rpc_clnt *clnt) { return NULL; }
static inline void rpc_count_iostats(const struct rpc_task *task,
struct rpc_iostats *stats) {}
static inline void rpc_print_iostats(struct seq_file *seq, struct rpc_clnt *clnt) {}
static inline void rpc_free_iostats(struct rpc_iostats *stats) {}

#endif /* CONFIG_PROC_FS */

#endif /* _LINUX_SUNRPC_METRICS_H */