xref: /openbmc/linux/include/linux/nfs_iostat.h (revision 0631d5e0)
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  */
62 enum 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  */
91 enum 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 */
123