metrics.h

  1/* SPDX-License-Identifier: GPL-2.0 */
  2/*
  3 *  linux/include/linux/sunrpc/metrics.h
  4 *
  5 *  Declarations for RPC client per-operation metrics
  6 *
  7 *  Copyright (C) 2005	Chuck Lever <cel@netapp.com>
  8 *
  9 *  RPC client per-operation statistics provide latency and retry
 10 *  information about each type of RPC procedure in a given RPC program.
 11 *  These statistics are not for detailed problem diagnosis, but simply
 12 *  to indicate whether the problem is local or remote.
 13 *
 14 *  These counters are not meant to be human-readable, but are meant to be
 15 *  integrated into system monitoring tools such as "sar" and "iostat".  As
 16 *  such, the counters are sampled by the tools over time, and are never
 17 *  zeroed after a file system is mounted.  Moving averages can be computed
 18 *  by the tools by taking the difference between two instantaneous samples
 19 *  and dividing that by the time between the samples.
 20 *
 21 *  The counters are maintained in a single array per RPC client, indexed
 22 *  by procedure number.  There is no need to maintain separate counter
 23 *  arrays per-CPU because these counters are always modified behind locks.
 24 */
 25
 26#ifndef _LINUX_SUNRPC_METRICS_H
 27#define _LINUX_SUNRPC_METRICS_H
 28
 29#include <linux/seq_file.h>
 30#include <linux/ktime.h>
 31#include <linux/spinlock.h>
 32
 33#define RPC_IOSTATS_VERS	"1.1"
 34
 35struct rpc_iostats {
 36	spinlock_t		om_lock;
 37
 38	/*
 39	 * These counters give an idea about how many request
 40	 * transmissions are required, on average, to complete that
 41	 * particular procedure.  Some procedures may require more
 42	 * than one transmission because the server is unresponsive,
 43	 * the client is retransmitting too aggressively, or the
 44	 * requests are large and the network is congested.
 45	 */
 46	unsigned long		om_ops,		/* count of operations */
 47				om_ntrans,	/* count of RPC transmissions */
 48				om_timeouts;	/* count of major timeouts */
 49
 50	/*
 51	 * These count how many bytes are sent and received for a
 52	 * given RPC procedure type.  This indicates how much load a
 53	 * particular procedure is putting on the network.  These
 54	 * counts include the RPC and ULP headers, and the request
 55	 * payload.
 56	 */
 57	unsigned long long      om_bytes_sent,	/* count of bytes out */
 58				om_bytes_recv;	/* count of bytes in */
 59
 60	/*
 61	 * The length of time an RPC request waits in queue before
 62	 * transmission, the network + server latency of the request,
 63	 * and the total time the request spent from init to release
 64	 * are measured.
 65	 */
 66	ktime_t			om_queue,	/* queued for xmit */
 67				om_rtt,		/* RPC RTT */
 68				om_execute;	/* RPC execution */
 69	/*
 70	 * The count of operations that complete with tk_status < 0.
 71	 * These statuses usually indicate error conditions.
 72	 */
 73	unsigned long           om_error_status;
 74} ____cacheline_aligned;
 75
 76struct rpc_task;
 77struct rpc_clnt;
 78
 79/*
 80 * EXPORTed functions for managing rpc_iostats structures
 81 */
 82
 83#ifdef CONFIG_PROC_FS
 84
 85struct rpc_iostats *	rpc_alloc_iostats(struct rpc_clnt *);
 86void			rpc_count_iostats(const struct rpc_task *,
 87					  struct rpc_iostats *);
 88void			rpc_count_iostats_metrics(const struct rpc_task *,
 89					  struct rpc_iostats *);
 90void			rpc_clnt_show_stats(struct seq_file *, struct rpc_clnt *);
 91void			rpc_free_iostats(struct rpc_iostats *);
 92
 93#else  /*  CONFIG_PROC_FS  */
 94
 95static inline struct rpc_iostats *rpc_alloc_iostats(struct rpc_clnt *clnt) { return NULL; }
 96static inline void rpc_count_iostats(const struct rpc_task *task,
 97				     struct rpc_iostats *stats) {}
 98static inline void rpc_count_iostats_metrics(const struct rpc_task *task,
 99					     struct rpc_iostats *stats)
100{
101}
102
103static inline void rpc_clnt_show_stats(struct seq_file *seq, struct rpc_clnt *clnt) {}
104static inline void rpc_free_iostats(struct rpc_iostats *stats) {}
105
106#endif  /*  CONFIG_PROC_FS  */
107
108#endif /* _LINUX_SUNRPC_METRICS_H */