LXR linux/include/linux/sunrpc/metrics.h

   1/*
   2 *  linux/include/linux/sunrpc/metrics.h
   3 *
   4 *  Declarations for RPC client per-operation metrics
   5 *
   6 *  Copyright (C) 2005  Chuck Lever <cel@netapp.com>
   7 *
   8 *  RPC client per-operation statistics provide latency and retry
   9 *  information about each type of RPC procedure in a given RPC program.
  10 *  These statistics are not for detailed problem diagnosis, but simply
  11 *  to indicate whether the problem is local or remote.
  12 *
  13 *  These counters are not meant to be human-readable, but are meant to be
  14 *  integrated into system monitoring tools such as "sar" and "iostat".  As
  15 *  such, the counters are sampled by the tools over time, and are never
  16 *  zeroed after a file system is mounted.  Moving averages can be computed
  17 *  by the tools by taking the difference between two instantaneous samples
  18 *  and dividing that by the time between the samples.
  19 *
  20 *  The counters are maintained in a single array per RPC client, indexed
  21 *  by procedure number.  There is no need to maintain separate counter
  22 *  arrays per-CPU because these counters are always modified behind locks.
  23 */
  24
  25#ifndef _LINUX_SUNRPC_METRICS_H
  26#define _LINUX_SUNRPC_METRICS_H
  27
  28#include <linux/seq_file.h>
  29#include <linux/ktime.h>
  30
  31#define RPC_IOSTATS_VERS        "1.0"
  32
  33struct rpc_iostats {
  34        /*
  35         * These counters give an idea about how many request
  36         * transmissions are required, on average, to complete that
  37         * particular procedure.  Some procedures may require more
  38         * than one transmission because the server is unresponsive,
  39         * the client is retransmitting too aggressively, or the
  40         * requests are large and the network is congested.
  41         */
  42        unsigned long           om_ops,         /* count of operations */
  43                                om_ntrans,      /* count of RPC transmissions */
  44                                om_timeouts;    /* count of major timeouts */
  45
  46        /*
  47         * These count how many bytes are sent and received for a
  48         * given RPC procedure type.  This indicates how much load a
  49         * particular procedure is putting on the network.  These
  50         * counts include the RPC and ULP headers, and the request
  51         * payload.
  52         */
  53        unsigned long long      om_bytes_sent,  /* count of bytes out */
  54                                om_bytes_recv;  /* count of bytes in */
  55
  56        /*
  57         * The length of time an RPC request waits in queue before
  58         * transmission, the network + server latency of the request,
  59         * and the total time the request spent from init to release
  60         * are measured.
  61         */
  62        ktime_t                 om_queue,       /* queued for xmit */
  63                                om_rtt,         /* RPC RTT */
  64                                om_execute;     /* RPC execution */
  65} ____cacheline_aligned;
  66
  67struct rpc_task;
  68struct rpc_clnt;
  69
  70/*
  71 * EXPORTed functions for managing rpc_iostats structures
  72 */
  73
  74#ifdef CONFIG_PROC_FS
  75
  76struct rpc_iostats *    rpc_alloc_iostats(struct rpc_clnt *);
  77void                    rpc_count_iostats(const struct rpc_task *,
  78                                          struct rpc_iostats *);
  79void                    rpc_print_iostats(struct seq_file *, struct rpc_clnt *);
  80void                    rpc_free_iostats(struct rpc_iostats *);
  81
  82#else  /*  CONFIG_PROC_FS  */
  83
  84static inline struct rpc_iostats *rpc_alloc_iostats(struct rpc_clnt *clnt) { return NULL; }
  85static inline void rpc_count_iostats(const struct rpc_task *task,
  86                                     struct rpc_iostats *stats) {}
  87static inline void rpc_print_iostats(struct seq_file *seq, struct rpc_clnt *clnt) {}
  88static inline void rpc_free_iostats(struct rpc_iostats *stats) {}
  89
  90#endif  /*  CONFIG_PROC_FS  */
  91
  92#endif /* _LINUX_SUNRPC_METRICS_H */
  93