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
  33 struct 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
  67 struct rpc_task;
  68 struct rpc_clnt;
  69
  70 /*
  71  * EXPORTed functions for managing rpc_iostats structures
  72  */
  73
  74 #ifdef CONFIG_PROC_FS
  75
  76 struct rpc_iostats *    rpc_alloc_iostats(struct rpc_clnt *);
  77 void                    rpc_count_iostats(const struct rpc_task *,
  78                                           struct rpc_iostats *);
  79 void                    rpc_print_iostats(struct seq_file *, struct rpc_clnt *);
  80 void                    rpc_free_iostats(struct rpc_iostats *);
  81
  82 #else  /*  CONFIG_PROC_FS  */
  83
  84 static inline struct rpc_iostats *rpc_alloc_iostats(struct rpc_clnt *clnt) { return NULL; }
  85 static inline void rpc_count_iostats(const struct rpc_task *task,
  86                                      struct rpc_iostats *stats) {}
  87 static inline void rpc_print_iostats(struct seq_file *seq, struct rpc_clnt *clnt) {}
  88 static inline void rpc_free_iostats(struct rpc_iostats *stats) {}
  89
  90 #endif  /*  CONFIG_PROC_FS  */
  91
  92 #endif /* _LINUX_SUNRPC_METRICS_H */