LXR linux/include/linux/sunrpc/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 */
 109