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
  30#define RPC_IOSTATS_VERS        "1.0"
  31
  32struct rpc_iostats {
  33        /*
  34         * These counters give an idea about how many request
  35         * transmissions are required, on average, to complete that
  36         * particular procedure.  Some procedures may require more
  37         * than one transmission because the server is unresponsive,
  38         * the client is retransmitting too aggressively, or the
  39         * requests are large and the network is congested.
  40         */
  41        unsigned long           om_ops,         /* count of operations */
  42                                om_ntrans,      /* count of RPC transmissions */
  43                                om_timeouts;    /* count of major timeouts */
  44
  45        /*
  46         * These count how many bytes are sent and received for a
  47         * given RPC procedure type.  This indicates how much load a
  48         * particular procedure is putting on the network.  These
  49         * counts include the RPC and ULP headers, and the request
  50         * payload.
  51         */
  52        unsigned long long      om_bytes_sent,  /* count of bytes out */
  53                                om_bytes_recv;  /* count of bytes in */
  54
  55        /*
  56         * The length of time an RPC request waits in queue before
  57         * transmission, the network + server latency of the request,
  58         * and the total time the request spent from init to release
  59         * are measured.
  60         */
  61        unsigned long long      om_queue,       /* jiffies queued for xmit */
  62                                om_rtt,         /* jiffies for RPC RTT */
  63                                om_execute;     /* jiffies for RPC execution */
  64} ____cacheline_aligned;
  65
  66struct rpc_task;
  67struct rpc_clnt;
  68
  69/*
  70 * EXPORTed functions for managing rpc_iostats structures
  71 */
  72
  73#ifdef CONFIG_PROC_FS
  74
  75struct rpc_iostats *    rpc_alloc_iostats(struct rpc_clnt *);
  76void                    rpc_count_iostats(struct rpc_task *);
  77void                    rpc_print_iostats(struct seq_file *, struct rpc_clnt *);
  78void                    rpc_free_iostats(struct rpc_iostats *);
  79
  80#else  /*  CONFIG_PROC_FS  */
  81
  82static inline struct rpc_iostats *rpc_alloc_iostats(struct rpc_clnt *clnt) { return NULL; }
  83static inline void rpc_count_iostats(struct rpc_task *task) {}
  84static inline void rpc_print_iostats(struct seq_file *seq, struct rpc_clnt *clnt) {}
  85static inline void rpc_free_iostats(struct rpc_iostats *stats) {}
  86
  87#endif  /*  CONFIG_PROC_FS  */
  88
  89#endif /* _LINUX_SUNRPC_METRICS_H */
  90