/*
* User-space visible declarations for NFS client per-mount
* point statistics
*
* Copyright (C) 2005, 2006 Chuck Lever <[email protected]>
*
* NFS client per-mount statistics provide information about the
* health of the NFS client and the health of each NFS mount point.
* Generally these are not for detailed problem diagnosis, but
* simply to indicate that there is a problem.
*
* These counters are not meant to be human-readable, but are meant
* to be integrated into system monitoring tools such as "sar" and
* "iostat". As such, the counters are sampled by the tools over
* time, and are never zeroed after a file system is mounted.
* Moving averages can be computed by the tools by taking the
* difference between two instantaneous samples and dividing that
* by the time between the samples.
*/

#ifndef _LINUX_NFS_IOSTAT
#define _LINUX_NFS_IOSTAT

#define NFS_IOSTAT_VERS "1.1"

/*
* NFS byte counters
*
* 1. SERVER - the number of payload bytes read from or written
* to the server by the NFS client via an NFS READ or WRITE
* request.
*
* 2. NORMAL - the number of bytes read or written by applications
* via the read(2) and write(2) system call interfaces.
*
* 3. DIRECT - the number of bytes read or written from files
* opened with the O_DIRECT flag.
*
* These counters give a view of the data throughput into and out
* of the NFS client. Comparing the number of bytes requested by
* an application with the number of bytes the client requests from
* the server can provide an indication of client efficiency
* (per-op, cache hits, etc).
*
* These counters can also help characterize which access methods
* are in use. DIRECT by itself shows whether there is any O_DIRECT
* traffic. NORMAL + DIRECT shows how much data is going through
* the system call interface. A large amount of SERVER traffic
* without much NORMAL or DIRECT traffic shows that applications
* are using mapped files.
*
* NFS page counters
*
* These count the number of pages read or written via nfs_readpage(),
* nfs_readpages(), or their write equivalents.
*
* NB: When adding new byte counters, please include the measured
* units in the name of each byte counter to help users of this
* interface determine what exactly is being counted.
*/
enum nfs_stat_bytecounters {
NFSIOS_NORMALREADBYTES = 0,
NFSIOS_NORMALWRITTENBYTES,
NFSIOS_DIRECTREADBYTES,
NFSIOS_DIRECTWRITTENBYTES,
NFSIOS_SERVERREADBYTES,
NFSIOS_SERVERWRITTENBYTES,
NFSIOS_READPAGES,
NFSIOS_WRITEPAGES,
__NFSIOS_BYTESMAX,
};

/*
* NFS event counters
*
* These counters provide a low-overhead way of monitoring client
* activity without enabling NFS trace debugging. The counters
* show the rate at which VFS requests are made, and how often the
* client invalidates its data and attribute caches. This allows
* system administrators to monitor such things as how close-to-open
* is working, and answer questions such as "why are there so many
* GETATTR requests on the wire?"
*
* They also count anamolous events such as short reads and writes,
* silly renames due to close-after-delete, and operations that
* change the size of a file (such operations can often be the
* source of data corruption if applications aren't using file
* locking properly).
*/
enum nfs_stat_eventcounters {
NFSIOS_INODEREVALIDATE = 0,
NFSIOS_DENTRYREVALIDATE,
NFSIOS_DATAINVALIDATE,
NFSIOS_ATTRINVALIDATE,
NFSIOS_VFSOPEN,
NFSIOS_VFSLOOKUP,
NFSIOS_VFSACCESS,
NFSIOS_VFSUPDATEPAGE,
NFSIOS_VFSREADPAGE,
NFSIOS_VFSREADPAGES,
NFSIOS_VFSWRITEPAGE,
NFSIOS_VFSWRITEPAGES,
NFSIOS_VFSGETDENTS,
NFSIOS_VFSSETATTR,
NFSIOS_VFSFLUSH,
NFSIOS_VFSFSYNC,
NFSIOS_VFSLOCK,
NFSIOS_VFSRELEASE,
NFSIOS_CONGESTIONWAIT,
NFSIOS_SETATTRTRUNC,
NFSIOS_EXTENDWRITE,
NFSIOS_SILLYRENAME,
NFSIOS_SHORTREAD,
NFSIOS_SHORTWRITE,
NFSIOS_DELAY,
NFSIOS_PNFS_READ,
NFSIOS_PNFS_WRITE,
__NFSIOS_COUNTSMAX,
};

/*
* NFS local caching servicing counters
*/
enum nfs_stat_fscachecounters {
NFSIOS_FSCACHE_PAGES_READ_OK,
NFSIOS_FSCACHE_PAGES_READ_FAIL,
NFSIOS_FSCACHE_PAGES_WRITTEN_OK,
NFSIOS_FSCACHE_PAGES_WRITTEN_FAIL,
NFSIOS_FSCACHE_PAGES_UNCACHED,
__NFSIOS_FSCACHEMAX,
};

#endif /* _LINUX_NFS_IOSTAT */