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fio
Langue: en
Version: 111216 (mandriva - 01/05/08)
Section: 1 (Commandes utilisateur)
Sommaire
NAME
fio - flexible I/O testerSYNOPSIS
fio [options] [jobfile]...DESCRIPTION
fio is a tool that will spawn a number of threads or processes doing a particular type of I/O action as specified by the user. The typical use of fio is to write a job file matching the I/O load one wants to simulate.OPTIONS
- --output=filename
- Write output to filename.
- --timeout=timeout
- Limit run time to timeout seconds.
- --latency-log
- Generate per-job latency logs.
- --bandwidth-log
- Generate per-job bandwidth logs.
- --minimal
- Print statistics in a terse, semicolon-delimited format.
- --showcmd=jobfile
- Convert jobfile to a set of command-line options.
- --readonly
- Enable read-only safety checks.
- --eta=when
- Specifies when real-time ETA estimate should be printed. when may be one of `always', `never' or `auto'.
- --cmdhelp=command
- Print help information for command. May be `all' for all commands.
- --debug=type
- Enable verbose tracing of various fio actions. May be `all' for all types or individual types seperated by a comma (eg --debug=io,file). `help' will list all available tracing options.
- Print help information for command. May be `all' for all commands.
- --help
- Display usage information and exit.
- --version
- Display version information and exit.
JOB FILE FORMAT
Job files are in `ini' format. They consist of one or more job definitions, which begin with a job name in square brackets and extend to the next job name. The job name can be any ASCII string except `global', which has a special meaning. Following the job name is a sequence of zero or more parameters, one per line, that define the behavior of the job. Any line starting with a `;' or `#' character is considered a comment and ignored.If jobfile is specified as `-', the job file will be read from standard input.
Global Section
The global section contains default parameters for jobs specified in the job file. A job is only affected by global sections residing above it, and there may be any number of global sections. Specific job definitions may override any parameter set in global sections.JOB PARAMETERS
Types
Some parameters may take arguments of a specific type. The types used are:- str
- String: a sequence of alphanumeric characters.
- int
- Integer: a whole number, possibly negative. If prefixed with `0x', the value is assumed to be base 16 (hexadecimal).
- siint
- SI integer: a whole number, possibly containing a suffix denoting the base unit of the value. Accepted suffixes are `k', 'M' and 'G', denoting kilo (1024), mega (1024*1024) and giga (1024*1024*1024) respectively.
- bool
- Boolean: a true or false value. `0' denotes false, `1' denotes true.
- irange
- Integer range: a range of integers specified in the format lower:upper or lower-upper. lower and upper may contain a suffix as described above. If an option allows two sets of ranges, they are separated with a `,' or `/' character. For example: `8-8k/8M-4G'.
Parameter List
- name=str
- May be used to override the job name. On the command line, this parameter has the special purpose of signalling the start of a new job.
- description=str
- Human-readable description of the job. It is printed when the job is run, but otherwise has no special purpose.
- directory=str
- Prefix filenames with this directory. Used to place files in a location other than `./'.
- filename=str
- fio normally makes up a file name based on the job name, thread number, and file number. If you want to share files between threads in a job or several jobs, specify a filename for each of them to override the default. If the I/O engine used is `net', filename is the host and port to connect to in the format host/port. If the I/O engine is file-based, you can specify a number of files by separating the names with a `:' character. `-' is a reserved name, meaning stdin or stdout, depending on the read/write direction set.
- opendir=str
- Recursively open any files below directory str.
- readwrite=str, rw=str
- Type of I/O pattern. Accepted values are:
-
-
- read
- Sequential reads.
- write
- Sequential writes.
- randread
- Random reads.
- randwrite
- Random writes.
- rw
- Mixed sequential reads and writes.
- randrw
- Mixed random reads and writes.
For mixed I/O, the default split is 50/50. For random I/O, the number of I/Os to perform before getting a new offset can be specified by appending `:int' to the pattern type. The default is 1.
-
-
- randrepeat=bool
- Seed the random number generator in a predictable way so results are repeatable across runs. Default: true.
- fadvise_hint=bool
- Disable use of posix_fadvise(2) to advise the kernel what I/O patterns are likely to be issued. Default: true.
- size=siint
- Total size of I/O for this job. fio will run until this many bytes have been transfered, unless limited by other options (runtime, for instance). Unless nr_files and filesize options are given, this amount will be divided between the available files for the job.
- filesize=irange
- Individual file sizes. May be a range, in which case fio will select sizes for files at random within the given range, limited to size in total (if that is given). If filesize is not specified, each created file is the same size.
- blocksize=siint[,siint], bs=siint[,siint]
- Block size for I/O units. Default: 4k. Values for reads and writes can be specified seperately in the format read,write, either of which may be empty to leave that value at its default.
- blocksize_range=irange[,irange], bsrange=irange[,irange]
- Specify a range of I/O block sizes. The issued I/O unit will always be a multiple of the minimum size, unless blocksize_unaligned is set. Applies to both reads and writes if only one range is given, but can be specified seperately with a comma seperating the values. Example: bsrange=1k-4k,2k-8k. Also (see blocksize).
- bssplit=str
- This option allows even finer grained control of the block sizes issued, not just even splits between them. With this option, you can weight various block sizes for exact control of the issued IO for a job that has mixed block sizes. The format of the option is bssplit=blocksize/percentage, optionally adding as many definitions as needed seperated by a colon. Example: bssplit=4k/10:64k/50:32k/40 would issue 50% 64k blocks, 10% 4k blocks and 40% 32k blocks.
- blocksize_unaligned, bs_unaligned
- If set, any size in blocksize_range may be used. This typically won't work with direct I/O, as that normally requires sector alignment.
- zero_buffers
- Initialise buffers with all zeros. Default: fill buffers with random data.
- nrfiles=int
- Number of files to use for this job. Default: 1.
- openfiles=int
- Number of files to keep open at the same time. Default: nrfiles.
- file_service_type=str
- Defines how files to service are selected. The following types are defined:
-
-
- random
- Choose a file at random
- roundrobin
- Round robin over open files (default).
The number of I/Os to issue before switching a new file can be specified by appending `:int' to the service type.
-
-
- ioengine=str
- Defines how the job issues I/O. The following types are defined:
-
-
- sync
- Basic read(2) or write(2) I/O. fseek(2) is used to position the I/O location.
- psync
- Basic pread(2) or pwrite(2) I/O.
- vsync
- Basic readv(2) or writev(2) I/O. Will emulate queuing by coalescing adjacents IOs into a single submission.
- libaio
- Linux native asynchronous I/O.
- posixaio
- glibc POSIX asynchronous I/O using aio_read(3) and aio_write(3).
- mmap
- File is memory mapped with mmap(2) and data copied using memcpy(3).
- splice
- splice(2) is used to transfer the data and vmsplice(2) to transfer data from user-space to the kernel.
- syslet-rw
- Use the syslet system calls to make regular read/write asynchronous.
- sg
- SCSI generic sg v3 I/O. May be either synchronous using the SG_IO ioctl, or if the target is an sg character device, we use read(2) and write(2) for asynchronous I/O.
- null
- Doesn't transfer any data, just pretends to. Mainly used to exercise fio itself and for debugging and testing purposes.
- net
- Transfer over the network. filename must be set appropriately to `host/port' regardless of data direction. If receiving, only the port argument is used.
- netsplice
- Like net, but uses splice(2) and vmsplice(2) to map data and send/receive.
- cpuio
- Doesn't transfer any data, but burns CPU cycles according to cpuload and cpucycles parameters.
- guasi
- The GUASI I/O engine is the Generic Userspace Asynchronous Syscall Interface approach to asycnronous I/O.
See <http://www.xmailserver.org/guasi-lib.html>. - external
- Loads an external I/O engine object file. Append the engine filename as `:enginepath'.
-
-
- iodepth=int
- Number of I/O units to keep in flight against the file. Default: 1.
- iodepth_batch=int
- Number of I/Os to submit at once. Default: iodepth.
- iodepth_low=int
- Low watermark indicating when to start filling the queue again. Default: iodepth.
- direct=bool
- If true, use non-buffered I/O (usually O_DIRECT). Default: false.
- buffered=bool
- If true, use buffered I/O. This is the opposite of the direct parameter. Default: true.
- offset=siint
- Offset in the file to start I/O. Data before the offset will not be touched.
- fsync=int
- How many I/Os to perform before issuing an fsync(2) of dirty data. If 0, don't sync. Default: 0.
- overwrite=bool
- If writing, setup the file first and do overwrites. Default: false.
- end_fsync=bool
- Sync file contents when job exits. Default: false.
- fsync_on_close=bool
- If true, sync file contents on close. This differs from end_fsync in that it will happen on every close, not just at the end of the job. Default: false.
- rwmixcycle=int
- How many milliseconds before switching between reads and writes for a mixed workload. Default: 500ms.
- rwmixread=int
- Percentage of a mixed workload that should be reads. Default: 50.
- rwmixwrite=int
- Percentage of a mixed workload that should be writes. If rwmixread and wrmixwrite are given and do not sum to 100%, the latter of the two overrides the first. Default: 50.
- norandommap
- Normally fio will cover every block of the file when doing random I/O. If this parameter is given, a new offset will be chosen without looking at past I/O history. This parameter is mutually exclusive with verify.
- nice=int
- Run job with given nice value. See nice(2).
- prio=int
- Set I/O priority value of this job between 0 (highest) and 7 (lowest). See ionice(1).
- prioclass=int
- Set I/O priority class. See ionice(1).
- thinktime=int
- Stall job for given number of microseconds between issuing I/Os.
- thinktime_spin=int
- Pretend to spend CPU time for given number of microseconds, sleeping the rest of the time specified by thinktime. Only valid if thinktime is set.
- thinktime_blocks=int
- Number of blocks to issue before waiting thinktime microseconds. Default: 1.
- rate=int
- Cap bandwidth used by this job to this number of KiB/s.
- ratemin=int
- Tell fio to do whatever it can to maintain at least the given bandwidth. Failing to meet this requirement will cause the job to exit.
- rate_iops=int
- Cap the bandwidth to this number of IOPS. If blocksize is a range, the smallest block size is used as the metric.
- rate_iops_min=int
- If this rate of I/O is not met, the job will exit.
- ratecycle=int
- Average bandwidth for rate and ratemin over this number of milliseconds. Default: 1000ms.
- cpumask=int
- Set CPU affinity for this job. int is a bitmask of allowed CPUs the job may run on. See sched_setaffinity(2).
- cpus_allowed=str
- Same as cpumask, but allows a comma-delimited list of CPU numbers.
- startdelay=int
- Delay start of job for the specified number of seconds.
- runtime=int
- Terminate processing after the specified number of seconds.
- time_based
- If given, run for the specified runtime duration even if the files are completely read or written. The same workload will be repeated as many times as runtime allows.
- invalidate=bool
- Invalidate buffer-cache for the file prior to starting I/O. Default: true.
- sync=bool
- Use synchronous I/O for buffered writes. For the majority of I/O engines, this means using O_SYNC. Default: false.
- iomem=str, mem=str
- Allocation method for I/O unit buffer. Allowed values are:
-
-
- malloc
- Allocate memory with malloc(3).
- shm
- Use shared memory buffers allocated through shmget(2).
- shmhuge
- Same as shm, but use huge pages as backing.
- mmap
- Use mmap(2) for allocation. Uses anonymous memory unless a filename is given after the option in the format `:file'.
- mmaphuge
- Same as mmap, but use huge files as backing.
The amount of memory allocated is the maximum allowed blocksize for the job multiplied by iodepth. For shmhuge or mmaphuge to work, the system must have free huge pages allocated. mmaphuge also needs to have hugetlbfs mounted, and file must point there.
-
-
- hugepage-size=siint
- Defines the size of a huge page. Must be at least equal to the system setting. Should be a multiple of 1MiB. Default: 4MiB.
- exitall
- Terminate all jobs when one finishes. Default: wait for each job to finish.
- bwavgtime=int
- Average bandwidth calculations over the given time in milliseconds. Default: 500ms.
- create_serialize=bool
- If true, serialize file creation for the jobs. Default: true.
- create_fsync=bool
- fsync(2) data file after creation. Default: true.
- unlink=bool
- Unlink job files when done. Default: false.
- loops=int
- Specifies the number of iterations (runs of the same workload) of this job. Default: 1.
- do_verify=bool
- Run the verify phase after a write phase. Only valid if verify is set. Default: true.
- verify=str
- Method of verifying file contents after each iteration of the job. Allowed values are:
-
-
- md5 crc16 crc32 crc64 crc7 sha256 sha512
- Store appropriate checksum in the header of each block.
- meta
- Write extra information about each I/O (timestamp, block number, etc.). The block number is verified.
- pattern
- Fill I/O buffers with a specific pattern that is used to verify. The pattern is specified by appending `:int' to the parameter. int cannot be larger than 32-bits.
- null
- Pretend to verify. Used for testing internals.
-
-
- verify_sort=bool
- If true, written verify blocks are sorted if fio deems it to be faster to read them back in a sorted manner. Default: true.
- verify_offset=siint
- Swap the verification header with data somewhere else in the block before writing. It is swapped back before verifying.
- verify_interval=siint
- Write the verification header for this number of bytes, which should divide blocksize. Default: blocksize.
- verify_fatal=bool
- If true, exit the job on the first observed verification failure. Default: false.
- stonewall
- Wait for preceeding jobs in the job file to exit before starting this one. stonewall implies new_group.
- new_group
- Start a new reporting group. If not given, all jobs in a file will be part of the same reporting group, unless separated by a stonewall.
- numjobs=int
- Number of clones (processes/threads performing the same workload) of this job. Default: 1.
- group_reporting
- If set, display per-group reports instead of per-job when numjobs is specified.
- thread
- Use threads created with pthread_create(3) instead of processes created with fork(2).
- zonesize=siint
- Divide file into zones of the specified size in bytes. See zoneskip.
- zoneskip=siint
- Skip the specified number of bytes when zonesize bytes of data have been read.
- write_iolog=str
- Write the issued I/O patterns to the specified file.
- read_iolog=str
- Replay the I/O patterns contained in the specified file generated by write_iolog, or may be a blktrace binary file.
- write_bw_log
- If given, write bandwidth logs of the jobs in this file.
- write_lat_log
- Same as write_bw_log, but writes I/O completion latencies.
- lockmem=siint
- Pin the specified amount of memory with mlock(2). Can be used to simulate a smaller amount of memory.
- exec_prerun=str
- Before running the job, execute the specified command with system(3).
- exec_postrun=str
- Same as exec_prerun, but the command is executed after the job completes.
- ioscheduler=str
- Attempt to switch the device hosting the file to the specified I/O scheduler.
- cpuload=int
- If the job is a CPU cycle-eater, attempt to use the specified percentage of CPU cycles.
- cpuchunks=int
- If the job is a CPU cycle-eater, split the load into cycles of the given time in milliseconds.
- disk_util=bool
- Generate disk utilization statistics if the platform supports it. Default: true.
OUTPUT
While running, fio will display the status of the created jobs. For example:
Threads: 1: [_r] [24.8% done] [ 13509/ 8334 kb/s] [eta 00h:01m:31s]
The characters in the first set of brackets denote the current status of each threads. The possible values are:
-
- P
- Setup but not started.
- C
- Thread created.
- I
- Initialized, waiting.
- R
- Running, doing sequential reads.
- r
- Running, doing random reads.
- W
- Running, doing sequential writes.
- w
- Running, doing random writes.
- M
- Running, doing mixed sequential reads/writes.
- m
- Running, doing mixed random reads/writes.
- F
- Running, currently waiting for fsync(2).
- V
- Running, verifying written data.
- E
- Exited, not reaped by main thread.
- -
- Exited, thread reaped.
The second set of brackets shows the estimated completion percentage of the current group. The third set shows the read and write I/O rate, respectively. Finally, the estimated run time of the job is displayed.
When fio completes (or is interrupted by Ctrl-C), it will show data for each thread, each group of threads, and each disk, in that order.
Per-thread statistics first show the threads client number, group-id, and error code. The remaining figures are as follows:
-
- io
- Number of megabytes of I/O performed.
- bw
- Average data rate (bandwidth).
- runt
- Threads run time.
- slat
- Submission latency minimum, maximum, average and standard deviation. This is the time it took to submit the I/O.
- clat
- Completion latency minimum, maximum, average and standard deviation. This is the time between submission and completion.
- bw
- Bandwidth minimum, maximum, percentage of aggregate bandwidth received, average and standard deviation.
- cpu
- CPU usage statistics. Includes user and system time, number of context switches this thread went through and number of major and minor page faults.
- IO depths
- Distribution of I/O depths. Each depth includes everything less than (or equal) to it, but greater than the previous depth.
- IO issued
- Number of read/write requests issued, and number of short read/write requests.
- IO latencies
- Distribution of I/O completion latencies. The numbers follow the same pattern as IO depths.
The group statistics show:
-
- io
- Number of megabytes I/O performed.
- aggrb
- Aggregate bandwidth of threads in the group.
- minb
- Minimum average bandwidth a thread saw.
- maxb
- Maximum average bandwidth a thread saw.
- mint
- Shortest runtime of threads in the group.
- maxt
- Longest runtime of threads in the group.
Finally, disk statistics are printed with reads first:
-
- ios
- Number of I/Os performed by all groups.
- merge
- Number of merges in the I/O scheduler.
- ticks
- Number of ticks we kept the disk busy.
- io_queue
- Total time spent in the disk queue.
- util
- Disk utilization.
TERSE OUTPUT
If the --minimal option is given, the results will be printed in a semicolon-delimited format suitable for scripted use. The fields are:- jobname, groupid, error
Read status: -
- KiB I/O, bandwidth (KiB/s), runtime (ms)
Submission latency: -
- min, max, mean, standard deviation
- min, max, mean, standard deviation
- min, max, aggregate percentage of total, mean, standard deviation
Write status:
- KiB I/O, bandwidth (KiB/s), runtime (ms)
Submission latency: -
- min, max, mean, standard deviation
- min, max, mean, standard deviation
- min, max, aggregate percentage of total, mean, standard deviation
CPU usage:
- user, system, context switches
IO depth distribution:
- <=1, 2, 4, 8, 16, 32, >=64
IO latency distribution (ms):
- <=2, 4, 10, 20, 50, 100, 250, 500, 750, 1000, >=2000
text description
- KiB I/O, bandwidth (KiB/s), runtime (ms)
AUTHORS
fio was written by Jens Axboe <jens.axboe@oracle.com>.This man page was written by Aaron Carroll <aaronc@cse.unsw.edu.au> based on documentation by Jens Axboe.
REPORTING BUGS
Report bugs to the fio mailing list <fio-devel@kernel.dk>. See README.SEE ALSO
For further documentation see HOWTO and README.Sample jobfiles are available in the examples directory.
Contenus ©2006-2024 Benjamin Poulain
Design ©2006-2024 Maxime Vantorre