nfs_iostat.h

  1/* SPDX-License-Identifier: GPL-2.0 */
  2/*
  3 *  User-space visible declarations for NFS client per-mount
  4 *  point statistics
  5 *
  6 *  Copyright (C) 2005, 2006 Chuck Lever <cel@netapp.com>
  7 *
  8 *  NFS client per-mount statistics provide information about the
  9 *  health of the NFS client and the health of each NFS mount point.
 10 *  Generally these are not for detailed problem diagnosis, but
 11 *  simply to indicate that there is a problem.
 12 *
 13 *  These counters are not meant to be human-readable, but are meant
 14 *  to be integrated into system monitoring tools such as "sar" and
 15 *  "iostat".  As such, the counters are sampled by the tools over
 16 *  time, and are never zeroed after a file system is mounted.
 17 *  Moving averages can be computed by the tools by taking the
 18 *  difference between two instantaneous samples  and dividing that
 19 *  by the time between the samples.
 20 */
 21
 22#ifndef _LINUX_NFS_IOSTAT
 23#define _LINUX_NFS_IOSTAT
 24
 25#define NFS_IOSTAT_VERS		"1.1"
 26
 27/*
 28 * NFS byte counters
 29 *
 30 * 1.  SERVER - the number of payload bytes read from or written
 31 *     to the server by the NFS client via an NFS READ or WRITE
 32 *     request.
 33 *
 34 * 2.  NORMAL - the number of bytes read or written by applications
 35 *     via the read(2) and write(2) system call interfaces.
 36 *
 37 * 3.  DIRECT - the number of bytes read or written from files
 38 *     opened with the O_DIRECT flag.
 39 *
 40 * These counters give a view of the data throughput into and out
 41 * of the NFS client.  Comparing the number of bytes requested by
 42 * an application with the number of bytes the client requests from
 43 * the server can provide an indication of client efficiency
 44 * (per-op, cache hits, etc).
 45 *
 46 * These counters can also help characterize which access methods
 47 * are in use.  DIRECT by itself shows whether there is any O_DIRECT
 48 * traffic.  NORMAL + DIRECT shows how much data is going through
 49 * the system call interface.  A large amount of SERVER traffic
 50 * without much NORMAL or DIRECT traffic shows that applications
 51 * are using mapped files.
 52 *
 53 * NFS page counters
 54 *
 55 * These count the number of pages read or written via nfs_readpage(),
 56 * nfs_readpages(), or their write equivalents.
 57 *
 58 * NB: When adding new byte counters, please include the measured
 59 * units in the name of each byte counter to help users of this
 60 * interface determine what exactly is being counted.
 61 */
 62enum nfs_stat_bytecounters {
 63	NFSIOS_NORMALREADBYTES = 0,
 64	NFSIOS_NORMALWRITTENBYTES,
 65	NFSIOS_DIRECTREADBYTES,
 66	NFSIOS_DIRECTWRITTENBYTES,
 67	NFSIOS_SERVERREADBYTES,
 68	NFSIOS_SERVERWRITTENBYTES,
 69	NFSIOS_READPAGES,
 70	NFSIOS_WRITEPAGES,
 71	__NFSIOS_BYTESMAX,
 72};
 73
 74/*
 75 * NFS event counters
 76 *
 77 * These counters provide a low-overhead way of monitoring client
 78 * activity without enabling NFS trace debugging.  The counters
 79 * show the rate at which VFS requests are made, and how often the
 80 * client invalidates its data and attribute caches.  This allows
 81 * system administrators to monitor such things as how close-to-open
 82 * is working, and answer questions such as "why are there so many
 83 * GETATTR requests on the wire?"
 84 *
 85 * They also count anamolous events such as short reads and writes,
 86 * silly renames due to close-after-delete, and operations that
 87 * change the size of a file (such operations can often be the
 88 * source of data corruption if applications aren't using file
 89 * locking properly).
 90 */
 91enum nfs_stat_eventcounters {
 92	NFSIOS_INODEREVALIDATE = 0,
 93	NFSIOS_DENTRYREVALIDATE,
 94	NFSIOS_DATAINVALIDATE,
 95	NFSIOS_ATTRINVALIDATE,
 96	NFSIOS_VFSOPEN,
 97	NFSIOS_VFSLOOKUP,
 98	NFSIOS_VFSACCESS,
 99	NFSIOS_VFSUPDATEPAGE,
100	NFSIOS_VFSREADPAGE,
101	NFSIOS_VFSREADPAGES,
102	NFSIOS_VFSWRITEPAGE,
103	NFSIOS_VFSWRITEPAGES,
104	NFSIOS_VFSGETDENTS,
105	NFSIOS_VFSSETATTR,
106	NFSIOS_VFSFLUSH,
107	NFSIOS_VFSFSYNC,
108	NFSIOS_VFSLOCK,
109	NFSIOS_VFSRELEASE,
110	NFSIOS_CONGESTIONWAIT,
111	NFSIOS_SETATTRTRUNC,
112	NFSIOS_EXTENDWRITE,
113	NFSIOS_SILLYRENAME,
114	NFSIOS_SHORTREAD,
115	NFSIOS_SHORTWRITE,
116	NFSIOS_DELAY,
117	NFSIOS_PNFS_READ,
118	NFSIOS_PNFS_WRITE,
119	__NFSIOS_COUNTSMAX,
120};
121
122#endif	/* _LINUX_NFS_IOSTAT */