linux/include/linux/nfs_iostat.h
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   1/*
   2 *  User-space visible declarations for NFS client per-mount
   3 *  point statistics
   4 *
   5 *  Copyright (C) 2005, 2006 Chuck Lever <cel@netapp.com>
   6 *
   7 *  NFS client per-mount statistics provide information about the
   8 *  health of the NFS client and the health of each NFS mount point.
   9 *  Generally these are not for detailed problem diagnosis, but
  10 *  simply to indicate that there is a problem.
  11 *
  12 *  These counters are not meant to be human-readable, but are meant
  13 *  to be integrated into system monitoring tools such as "sar" and
  14 *  "iostat".  As such, the counters are sampled by the tools over
  15 *  time, and are never zeroed after a file system is mounted.
  16 *  Moving averages can be computed by the tools by taking the
  17 *  difference between two instantaneous samples  and dividing that
  18 *  by the time between the samples.
  19 */
  20
  21#ifndef _LINUX_NFS_IOSTAT
  22#define _LINUX_NFS_IOSTAT
  23
  24#define NFS_IOSTAT_VERS         "1.1"
  25
  26/*
  27 * NFS byte counters
  28 *
  29 * 1.  SERVER - the number of payload bytes read from or written
  30 *     to the server by the NFS client via an NFS READ or WRITE
  31 *     request.
  32 *
  33 * 2.  NORMAL - the number of bytes read or written by applications
  34 *     via the read(2) and write(2) system call interfaces.
  35 *
  36 * 3.  DIRECT - the number of bytes read or written from files
  37 *     opened with the O_DIRECT flag.
  38 *
  39 * These counters give a view of the data throughput into and out
  40 * of the NFS client.  Comparing the number of bytes requested by
  41 * an application with the number of bytes the client requests from
  42 * the server can provide an indication of client efficiency
  43 * (per-op, cache hits, etc).
  44 *
  45 * These counters can also help characterize which access methods
  46 * are in use.  DIRECT by itself shows whether there is any O_DIRECT
  47 * traffic.  NORMAL + DIRECT shows how much data is going through
  48 * the system call interface.  A large amount of SERVER traffic
  49 * without much NORMAL or DIRECT traffic shows that applications
  50 * are using mapped files.
  51 *
  52 * NFS page counters
  53 *
  54 * These count the number of pages read or written via nfs_readpage(),
  55 * nfs_readpages(), or their write equivalents.
  56 *
  57 * NB: When adding new byte counters, please include the measured
  58 * units in the name of each byte counter to help users of this
  59 * interface determine what exactly is being counted.
  60 */
  61enum nfs_stat_bytecounters {
  62        NFSIOS_NORMALREADBYTES = 0,
  63        NFSIOS_NORMALWRITTENBYTES,
  64        NFSIOS_DIRECTREADBYTES,
  65        NFSIOS_DIRECTWRITTENBYTES,
  66        NFSIOS_SERVERREADBYTES,
  67        NFSIOS_SERVERWRITTENBYTES,
  68        NFSIOS_READPAGES,
  69        NFSIOS_WRITEPAGES,
  70        __NFSIOS_BYTESMAX,
  71};
  72
  73/*
  74 * NFS event counters
  75 *
  76 * These counters provide a low-overhead way of monitoring client
  77 * activity without enabling NFS trace debugging.  The counters
  78 * show the rate at which VFS requests are made, and how often the
  79 * client invalidates its data and attribute caches.  This allows
  80 * system administrators to monitor such things as how close-to-open
  81 * is working, and answer questions such as "why are there so many
  82 * GETATTR requests on the wire?"
  83 *
  84 * They also count anamolous events such as short reads and writes,
  85 * silly renames due to close-after-delete, and operations that
  86 * change the size of a file (such operations can often be the
  87 * source of data corruption if applications aren't using file
  88 * locking properly).
  89 */
  90enum nfs_stat_eventcounters {
  91        NFSIOS_INODEREVALIDATE = 0,
  92        NFSIOS_DENTRYREVALIDATE,
  93        NFSIOS_DATAINVALIDATE,
  94        NFSIOS_ATTRINVALIDATE,
  95        NFSIOS_VFSOPEN,
  96        NFSIOS_VFSLOOKUP,
  97        NFSIOS_VFSACCESS,
  98        NFSIOS_VFSUPDATEPAGE,
  99        NFSIOS_VFSREADPAGE,
 100        NFSIOS_VFSREADPAGES,
 101        NFSIOS_VFSWRITEPAGE,
 102        NFSIOS_VFSWRITEPAGES,
 103        NFSIOS_VFSGETDENTS,
 104        NFSIOS_VFSSETATTR,
 105        NFSIOS_VFSFLUSH,
 106        NFSIOS_VFSFSYNC,
 107        NFSIOS_VFSLOCK,
 108        NFSIOS_VFSRELEASE,
 109        NFSIOS_CONGESTIONWAIT,
 110        NFSIOS_SETATTRTRUNC,
 111        NFSIOS_EXTENDWRITE,
 112        NFSIOS_SILLYRENAME,
 113        NFSIOS_SHORTREAD,
 114        NFSIOS_SHORTWRITE,
 115        NFSIOS_DELAY,
 116        NFSIOS_PNFS_READ,
 117        NFSIOS_PNFS_WRITE,
 118        __NFSIOS_COUNTSMAX,
 119};
 120
 121/*
 122 * NFS local caching servicing counters
 123 */
 124enum nfs_stat_fscachecounters {
 125        NFSIOS_FSCACHE_PAGES_READ_OK,
 126        NFSIOS_FSCACHE_PAGES_READ_FAIL,
 127        NFSIOS_FSCACHE_PAGES_WRITTEN_OK,
 128        NFSIOS_FSCACHE_PAGES_WRITTEN_FAIL,
 129        NFSIOS_FSCACHE_PAGES_UNCACHED,
 130        __NFSIOS_FSCACHEMAX,
 131};
 132
 133#endif  /* _LINUX_NFS_IOSTAT */
 134
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