include/linux/nfs_iostat.h

0001 /* SPDX-License-Identifier: GPL-2.0 */
0002 /*
0003  *  User-space visible declarations for NFS client per-mount
0004  *  point statistics
0005  *
0006  *  Copyright (C) 2005, 2006 Chuck Lever <cel@netapp.com>
0007  *
0008  *  NFS client per-mount statistics provide information about the
0009  *  health of the NFS client and the health of each NFS mount point.
0010  *  Generally these are not for detailed problem diagnosis, but
0011  *  simply to indicate that there is a problem.
0012  *
0013  *  These counters are not meant to be human-readable, but are meant
0014  *  to be integrated into system monitoring tools such as "sar" and
0015  *  "iostat".  As such, the counters are sampled by the tools over
0016  *  time, and are never zeroed after a file system is mounted.
0017  *  Moving averages can be computed by the tools by taking the
0018  *  difference between two instantaneous samples  and dividing that
0019  *  by the time between the samples.
0020  */
0021
0022 #ifndef _LINUX_NFS_IOSTAT
0023 #define _LINUX_NFS_IOSTAT
0024
0025 #define NFS_IOSTAT_VERS     "1.1"
0026
0027 /*
0028  * NFS byte counters
0029  *
0030  * 1.  SERVER - the number of payload bytes read from or written
0031  *     to the server by the NFS client via an NFS READ or WRITE
0032  *     request.
0033  *
0034  * 2.  NORMAL - the number of bytes read or written by applications
0035  *     via the read(2) and write(2) system call interfaces.
0036  *
0037  * 3.  DIRECT - the number of bytes read or written from files
0038  *     opened with the O_DIRECT flag.
0039  *
0040  * These counters give a view of the data throughput into and out
0041  * of the NFS client.  Comparing the number of bytes requested by
0042  * an application with the number of bytes the client requests from
0043  * the server can provide an indication of client efficiency
0044  * (per-op, cache hits, etc).
0045  *
0046  * These counters can also help characterize which access methods
0047  * are in use.  DIRECT by itself shows whether there is any O_DIRECT
0048  * traffic.  NORMAL + DIRECT shows how much data is going through
0049  * the system call interface.  A large amount of SERVER traffic
0050  * without much NORMAL or DIRECT traffic shows that applications
0051  * are using mapped files.
0052  *
0053  * NFS page counters
0054  *
0055  * These count the number of pages read or written via nfs_readpage(),
0056  * nfs_readpages(), or their write equivalents.
0057  *
0058  * NB: When adding new byte counters, please include the measured
0059  * units in the name of each byte counter to help users of this
0060  * interface determine what exactly is being counted.
0061  */
0062 enum nfs_stat_bytecounters {
0063     NFSIOS_NORMALREADBYTES = 0,
0064     NFSIOS_NORMALWRITTENBYTES,
0065     NFSIOS_DIRECTREADBYTES,
0066     NFSIOS_DIRECTWRITTENBYTES,
0067     NFSIOS_SERVERREADBYTES,
0068     NFSIOS_SERVERWRITTENBYTES,
0069     NFSIOS_READPAGES,
0070     NFSIOS_WRITEPAGES,
0071     __NFSIOS_BYTESMAX,
0072 };
0073
0074 /*
0075  * NFS event counters
0076  *
0077  * These counters provide a low-overhead way of monitoring client
0078  * activity without enabling NFS trace debugging.  The counters
0079  * show the rate at which VFS requests are made, and how often the
0080  * client invalidates its data and attribute caches.  This allows
0081  * system administrators to monitor such things as how close-to-open
0082  * is working, and answer questions such as "why are there so many
0083  * GETATTR requests on the wire?"
0084  *
0085  * They also count anamolous events such as short reads and writes,
0086  * silly renames due to close-after-delete, and operations that
0087  * change the size of a file (such operations can often be the
0088  * source of data corruption if applications aren't using file
0089  * locking properly).
0090  */
0091 enum nfs_stat_eventcounters {
0092     NFSIOS_INODEREVALIDATE = 0,
0093     NFSIOS_DENTRYREVALIDATE,
0094     NFSIOS_DATAINVALIDATE,
0095     NFSIOS_ATTRINVALIDATE,
0096     NFSIOS_VFSOPEN,
0097     NFSIOS_VFSLOOKUP,
0098     NFSIOS_VFSACCESS,
0099     NFSIOS_VFSUPDATEPAGE,
0100     NFSIOS_VFSREADPAGE,
0101     NFSIOS_VFSREADPAGES,
0102     NFSIOS_VFSWRITEPAGE,
0103     NFSIOS_VFSWRITEPAGES,
0104     NFSIOS_VFSGETDENTS,
0105     NFSIOS_VFSSETATTR,
0106     NFSIOS_VFSFLUSH,
0107     NFSIOS_VFSFSYNC,
0108     NFSIOS_VFSLOCK,
0109     NFSIOS_VFSRELEASE,
0110     NFSIOS_CONGESTIONWAIT,
0111     NFSIOS_SETATTRTRUNC,
0112     NFSIOS_EXTENDWRITE,
0113     NFSIOS_SILLYRENAME,
0114     NFSIOS_SHORTREAD,
0115     NFSIOS_SHORTWRITE,
0116     NFSIOS_DELAY,
0117     NFSIOS_PNFS_READ,
0118     NFSIOS_PNFS_WRITE,
0119     __NFSIOS_COUNTSMAX,
0120 };
0121
0122 /*
0123  * NFS local caching servicing counters
0124  */
0125 enum nfs_stat_fscachecounters {
0126     NFSIOS_FSCACHE_PAGES_READ_OK,
0127     NFSIOS_FSCACHE_PAGES_READ_FAIL,
0128     NFSIOS_FSCACHE_PAGES_WRITTEN_OK,
0129     NFSIOS_FSCACHE_PAGES_WRITTEN_FAIL,
0130     NFSIOS_FSCACHE_PAGES_UNCACHED,
0131     __NFSIOS_FSCACHEMAX,
0132 };
0133
0134 #endif  /* _LINUX_NFS_IOSTAT */