include/linux/nfs_iostat.h

   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         "1.0"
  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  */
  61 enum 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  */
  90 enum 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_COUNTSMAX,
 117 };
 118
 119 #endif  /* _LINUX_NFS_IOSTAT */