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_PNFS_READ,
117 	NFSIOS_PNFS_WRITE,
118 	__NFSIOS_COUNTSMAX,
119 };
120 
121 /*
122  * NFS local caching servicing counters
123  */
124 enum 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