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        "1.0"
  34
  35 struct 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 } ____cacheline_aligned;
  70
  71 struct rpc_task;
  72 struct rpc_clnt;
  73
  74 /*
  75  * EXPORTed functions for managing rpc_iostats structures
  76  */
  77
  78 #ifdef CONFIG_PROC_FS
  79
  80 struct rpc_iostats *    rpc_alloc_iostats(struct rpc_clnt *);
  81 void                    rpc_count_iostats(const struct rpc_task *,
  82                                           struct rpc_iostats *);
  83 void                    rpc_count_iostats_metrics(const struct rpc_task *,
  84                                           struct rpc_iostats *);
  85 void                    rpc_print_iostats(struct seq_file *, struct rpc_clnt *);
  86 void                    rpc_free_iostats(struct rpc_iostats *);
  87
  88 #else  /*  CONFIG_PROC_FS  */
  89
  90 static inline struct rpc_iostats *rpc_alloc_iostats(struct rpc_clnt *clnt) { return NULL; }
  91 static inline void rpc_count_iostats(const struct rpc_task *task,
  92                                      struct rpc_iostats *stats) {}
  93 static inline void rpc_count_iostats_metrics(const struct rpc_task *task,
  94                                              struct rpc_iostats *stats)
  95 {
  96 }
  97
  98 static inline void rpc_print_iostats(struct seq_file *seq, struct rpc_clnt *clnt) {}
  99 static inline void rpc_free_iostats(struct rpc_iostats *stats) {}
 100
 101 #endif  /*  CONFIG_PROC_FS  */
 102
 103 #endif /* _LINUX_SUNRPC_METRICS_H */