linux/sunrpc/metrics.h

0001 /* SPDX-License-Identifier: GPL-2.0 */
0002 /*
0003  *  linux/include/linux/sunrpc/metrics.h
0004  *
0005  *  Declarations for RPC client per-operation metrics
0006  *
0007  *  Copyright (C) 2005  Chuck Lever <cel@netapp.com>
0008  *
0009  *  RPC client per-operation statistics provide latency and retry
0010  *  information about each type of RPC procedure in a given RPC program.
0011  *  These statistics are not for detailed problem diagnosis, but simply
0012  *  to indicate whether the problem is local or remote.
0013  *
0014  *  These counters are not meant to be human-readable, but are meant to be
0015  *  integrated into system monitoring tools such as "sar" and "iostat".  As
0016  *  such, the counters are sampled by the tools over time, and are never
0017  *  zeroed after a file system is mounted.  Moving averages can be computed
0018  *  by the tools by taking the difference between two instantaneous samples
0019  *  and dividing that by the time between the samples.
0020  *
0021  *  The counters are maintained in a single array per RPC client, indexed
0022  *  by procedure number.  There is no need to maintain separate counter
0023  *  arrays per-CPU because these counters are always modified behind locks.
0024  */
0025
0026 #ifndef _LINUX_SUNRPC_METRICS_H
0027 #define _LINUX_SUNRPC_METRICS_H
0028
0029 #include <linux/seq_file.h>
0030 #include <linux/ktime.h>
0031 #include <linux/spinlock.h>
0032
0033 #define RPC_IOSTATS_VERS    "1.1"
0034
0035 struct rpc_iostats {
0036     spinlock_t      om_lock;
0037
0038     /*
0039      * These counters give an idea about how many request
0040      * transmissions are required, on average, to complete that
0041      * particular procedure.  Some procedures may require more
0042      * than one transmission because the server is unresponsive,
0043      * the client is retransmitting too aggressively, or the
0044      * requests are large and the network is congested.
0045      */
0046     unsigned long       om_ops,     /* count of operations */
0047                 om_ntrans,  /* count of RPC transmissions */
0048                 om_timeouts;    /* count of major timeouts */
0049
0050     /*
0051      * These count how many bytes are sent and received for a
0052      * given RPC procedure type.  This indicates how much load a
0053      * particular procedure is putting on the network.  These
0054      * counts include the RPC and ULP headers, and the request
0055      * payload.
0056      */
0057     unsigned long long      om_bytes_sent,  /* count of bytes out */
0058                 om_bytes_recv;  /* count of bytes in */
0059
0060     /*
0061      * The length of time an RPC request waits in queue before
0062      * transmission, the network + server latency of the request,
0063      * and the total time the request spent from init to release
0064      * are measured.
0065      */
0066     ktime_t         om_queue,   /* queued for xmit */
0067                 om_rtt,     /* RPC RTT */
0068                 om_execute; /* RPC execution */
0069     /*
0070      * The count of operations that complete with tk_status < 0.
0071      * These statuses usually indicate error conditions.
0072      */
0073     unsigned long           om_error_status;
0074 } ____cacheline_aligned;
0075
0076 struct rpc_task;
0077 struct rpc_clnt;
0078
0079 /*
0080  * EXPORTed functions for managing rpc_iostats structures
0081  */
0082
0083 #ifdef CONFIG_PROC_FS
0084
0085 struct rpc_iostats *    rpc_alloc_iostats(struct rpc_clnt *);
0086 void            rpc_count_iostats(const struct rpc_task *,
0087                       struct rpc_iostats *);
0088 void            rpc_count_iostats_metrics(const struct rpc_task *,
0089                       struct rpc_iostats *);
0090 void            rpc_clnt_show_stats(struct seq_file *, struct rpc_clnt *);
0091 void            rpc_free_iostats(struct rpc_iostats *);
0092
0093 #else  /*  CONFIG_PROC_FS  */
0094
0095 static inline struct rpc_iostats *rpc_alloc_iostats(struct rpc_clnt *clnt) { return NULL; }
0096 static inline void rpc_count_iostats(const struct rpc_task *task,
0097                      struct rpc_iostats *stats) {}
0098 static inline void rpc_count_iostats_metrics(const struct rpc_task *task,
0099                          struct rpc_iostats *stats)
0100 {
0101 }
0102
0103 static inline void rpc_clnt_show_stats(struct seq_file *seq, struct rpc_clnt *clnt) {}
0104 static inline void rpc_free_iostats(struct rpc_iostats *stats) {}
0105
0106 #endif  /*  CONFIG_PROC_FS  */
0107
0108 #endif /* _LINUX_SUNRPC_METRICS_H */