root/include/linux/sunrpc/metrics.h

INCLUDED FROM

DEFINITIONS

1. rpc_alloc_iostats
2. rpc_count_iostats
3. rpc_print_iostats
4. rpc_free_iostats

/*
 *  linux/include/linux/sunrpc/metrics.h
 *
 *  Declarations for RPC client per-operation metrics
 *
 *  Copyright (C) 2005  Chuck Lever <cel@netapp.com>
 *
 *  RPC client per-operation statistics provide latency and retry
 *  information about each type of RPC procedure in a given RPC program.
 *  These statistics are not for detailed problem diagnosis, but simply
 *  to indicate whether the problem is local or remote.
 *
 *  These counters are not meant to be human-readable, but are meant to be
 *  integrated into system monitoring tools such as "sar" and "iostat".  As
 *  such, the counters are sampled by the tools over time, and are never
 *  zeroed after a file system is mounted.  Moving averages can be computed
 *  by the tools by taking the difference between two instantaneous samples
 *  and dividing that by the time between the samples.
 *
 *  The counters are maintained in a single array per RPC client, indexed
 *  by procedure number.  There is no need to maintain separate counter
 *  arrays per-CPU because these counters are always modified behind locks.
 */

#ifndef _LINUX_SUNRPC_METRICS_H
#define _LINUX_SUNRPC_METRICS_H

#include <linux/seq_file.h>

#define RPC_IOSTATS_VERS        "1.0"

struct rpc_iostats {
        /*
         * These counters give an idea about how many request
         * transmissions are required, on average, to complete that
         * particular procedure.  Some procedures may require more
         * than one transmission because the server is unresponsive,
         * the client is retransmitting too aggressively, or the
         * requests are large and the network is congested.
         */
        unsigned long           om_ops,         /* count of operations */
                                om_ntrans,      /* count of RPC transmissions */
                                om_timeouts;    /* count of major timeouts */

        /*
         * These count how many bytes are sent and received for a
         * given RPC procedure type.  This indicates how much load a
         * particular procedure is putting on the network.  These
         * counts include the RPC and ULP headers, and the request
         * payload.
         */
        unsigned long long      om_bytes_sent,  /* count of bytes out */
                                om_bytes_recv;  /* count of bytes in */

        /*
         * The length of time an RPC request waits in queue before
         * transmission, the network + server latency of the request,
         * and the total time the request spent from init to release
         * are measured.
         */
        unsigned long long      om_queue,       /* jiffies queued for xmit */
                                om_rtt,         /* jiffies for RPC RTT */
                                om_execute;     /* jiffies for RPC execution */
} ____cacheline_aligned;

struct rpc_task;
struct rpc_clnt;

/*
 * EXPORTed functions for managing rpc_iostats structures
 */

#ifdef CONFIG_PROC_FS

struct rpc_iostats *    rpc_alloc_iostats(struct rpc_clnt *);
void                    rpc_count_iostats(struct rpc_task *);
void                    rpc_print_iostats(struct seq_file *, struct rpc_clnt *);
void                    rpc_free_iostats(struct rpc_iostats *);

#else  /*  CONFIG_PROC_FS  */

static inline struct rpc_iostats *rpc_alloc_iostats(struct rpc_clnt *clnt) { return NULL; }
static inline void rpc_count_iostats(struct rpc_task *task) {}
static inline void rpc_print_iostats(struct seq_file *seq, struct rpc_clnt *clnt) {}
static inline void rpc_free_iostats(struct rpc_iostats *stats) {}

#endif  /*  CONFIG_PROC_FS  */

#endif /* _LINUX_SUNRPC_METRICS_H */