1 .TH fio 1 "September 2007" "User Manual"
3 fio \- flexible I/O tester
6 [\fIoptions\fR] [\fIjobfile\fR]...
9 is a tool that will spawn a number of threads or processes doing a
10 particular type of I/O action as specified by the user.
11 The typical use of fio is to write a job file matching the I/O load
12 one wants to simulate.
15 .BI \-\-output \fR=\fPfilename
16 Write output to \fIfilename\fR.
18 .BI \-\-timeout \fR=\fPtimeout
19 Limit run time to \fItimeout\fR seconds.
22 Generate per-job latency logs.
25 Generate per-job bandwidth logs.
28 Print statistics in a terse, semicolon-delimited format.
30 .BI \-\-showcmd \fR=\fPjobfile
31 Convert \fIjobfile\fR to a set of command-line options.
34 Enable read-only safety checks.
36 .BI \-\-eta \fR=\fPwhen
37 Specifies when real-time ETA estimate should be printed. \fIwhen\fR may
38 be one of `always', `never' or `auto'.
40 .BI \-\-section \fR=\fPsec
41 Only run section \fIsec\fR from job file.
43 .BI \-\-cmdhelp \fR=\fPcommand
44 Print help information for \fIcommand\fR. May be `all' for all commands.
46 .BI \-\-debug \fR=\fPtype
47 Enable verbose tracing of various fio actions. May be `all' for all types
48 or individual types seperated by a comma (eg --debug=io,file). `help' will
49 list all available tracing options.
52 Display usage information and exit.
55 Display version information and exit.
57 Job files are in `ini' format. They consist of one or more
58 job definitions, which begin with a job name in square brackets and
59 extend to the next job name. The job name can be any ASCII string
60 except `global', which has a special meaning. Following the job name is
61 a sequence of zero or more parameters, one per line, that define the
62 behavior of the job. Any line starting with a `;' or `#' character is
63 considered a comment and ignored.
65 If \fIjobfile\fR is specified as `-', the job file will be read from
68 The global section contains default parameters for jobs specified in the
69 job file. A job is only affected by global sections residing above it,
70 and there may be any number of global sections. Specific job definitions
71 may override any parameter set in global sections.
74 Some parameters may take arguments of a specific type. The types used are:
77 String: a sequence of alphanumeric characters.
80 SI integer: a whole number, possibly containing a suffix denoting the base unit
81 of the value. Accepted suffixes are `k', 'M' and 'G', denoting kilo (1024),
82 mega (1024*1024) and giga (1024*1024*1024) respectively. If prefixed with '0x',
83 the value is assumed to be base 16 (hexadecimal).
86 Boolean: a true or false value. `0' denotes false, `1' denotes true.
89 Integer range: a range of integers specified in the format
90 \fIlower\fR:\fIupper\fR or \fIlower\fR\-\fIupper\fR. \fIlower\fR and
91 \fIupper\fR may contain a suffix as described above. If an option allows two
92 sets of ranges, they are separated with a `,' or `/' character. For example:
97 May be used to override the job name. On the command line, this parameter
98 has the special purpose of signalling the start of a new job.
100 .BI description \fR=\fPstr
101 Human-readable description of the job. It is printed when the job is run, but
102 otherwise has no special purpose.
104 .BI directory \fR=\fPstr
105 Prefix filenames with this directory. Used to place files in a location other
108 .BI filename \fR=\fPstr
110 normally makes up a file name based on the job name, thread number, and file
111 number. If you want to share files between threads in a job or several jobs,
112 specify a \fIfilename\fR for each of them to override the default. If the I/O
113 engine used is `net', \fIfilename\fR is the host and port to connect to in the
114 format \fIhost\fR/\fIport\fR. If the I/O engine is file-based, you can specify
115 a number of files by separating the names with a `:' character. `\-' is a
116 reserved name, meaning stdin or stdout, depending on the read/write direction
119 .BI opendir \fR=\fPstr
120 Recursively open any files below directory \fIstr\fR.
122 .BI readwrite \fR=\fPstr "\fR,\fP rw" \fR=\fPstr
123 Type of I/O pattern. Accepted values are:
140 Mixed sequential reads and writes.
143 Mixed random reads and writes.
146 For mixed I/O, the default split is 50/50. For random I/O, the number of I/Os
147 to perform before getting a new offset can be specified by appending
148 `:\fIint\fR' to the pattern type. The default is 1.
151 .BI randrepeat \fR=\fPbool
152 Seed the random number generator in a predictable way so results are repeatable
153 across runs. Default: true.
155 .BI fadvise_hint \fR=\fPbool
156 Disable use of \fIposix_fadvise\fR\|(2) to advise the kernel what I/O patterns
157 are likely to be issued. Default: true.
160 Total size of I/O for this job. \fBfio\fR will run until this many bytes have
161 been transfered, unless limited by other options (\fBruntime\fR, for instance).
162 Unless \fBnr_files\fR and \fBfilesize\fR options are given, this amount will be
163 divided between the available files for the job.
165 .BI filesize \fR=\fPirange
166 Individual file sizes. May be a range, in which case \fBfio\fR will select sizes
167 for files at random within the given range, limited to \fBsize\fR in total (if
168 that is given). If \fBfilesize\fR is not specified, each created file is the
171 .BI blocksize \fR=\fPint[,int] "\fR,\fB bs" \fR=\fPint[,int]
172 Block size for I/O units. Default: 4k. Values for reads and writes can be
173 specified seperately in the format \fIread\fR,\fIwrite\fR, either of
174 which may be empty to leave that value at its default.
176 .BI blocksize_range \fR=\fPirange[,irange] "\fR,\fB bsrange" \fR=\fPirange[,irange]
177 Specify a range of I/O block sizes. The issued I/O unit will always be a
178 multiple of the minimum size, unless \fBblocksize_unaligned\fR is set. Applies
179 to both reads and writes if only one range is given, but can be specified
180 seperately with a comma seperating the values. Example: bsrange=1k-4k,2k-8k.
181 Also (see \fBblocksize\fR).
183 .BI bssplit \fR=\fPstr
184 This option allows even finer grained control of the block sizes issued,
185 not just even splits between them. With this option, you can weight various
186 block sizes for exact control of the issued IO for a job that has mixed
187 block sizes. The format of the option is bssplit=blocksize/percentage,
188 optionally adding as many definitions as needed seperated by a colon.
189 Example: bssplit=4k/10:64k/50:32k/40 would issue 50% 64k blocks, 10% 4k
190 blocks and 40% 32k blocks. \fBbssplit\fR also supports giving separate
191 splits to reads and writes. The format is identical to what the
192 \fBbs\fR option accepts, the read and write parts are separated with a
195 .B blocksize_unaligned\fR,\fP bs_unaligned
196 If set, any size in \fBblocksize_range\fR may be used. This typically won't
197 work with direct I/O, as that normally requires sector alignment.
199 .BI blockalign \fR=\fPint[,int] "\fR,\fB ba" \fR=\fPint[,int]
200 At what boundary to align random IO offsets. Defaults to the same as 'blocksize'
201 the minimum blocksize given. Minimum alignment is typically 512b
202 for using direct IO, though it usually depends on the hardware block size.
203 This option is mutually exclusive with using a random map for files, so it
204 will turn off that option.
207 Initialise buffers with all zeros. Default: fill buffers with random data.
210 If this option is given, fio will refill the IO buffers on every submit. The
211 default is to only fill it at init time and reuse that data. Only makes sense
212 if zero_buffers isn't specified, naturally. If data verification is enabled,
213 refill_buffers is also automatically enabled.
215 .BI nrfiles \fR=\fPint
216 Number of files to use for this job. Default: 1.
218 .BI openfiles \fR=\fPint
219 Number of files to keep open at the same time. Default: \fBnrfiles\fR.
221 .BI file_service_type \fR=\fPstr
222 Defines how files to service are selected. The following types are defined:
227 Choose a file at random
230 Round robin over open files (default).
232 Do each file in the set sequentially.
235 The number of I/Os to issue before switching a new file can be specified by
236 appending `:\fIint\fR' to the service type.
239 .BI ioengine \fR=\fPstr
240 Defines how the job issues I/O. The following types are defined:
245 Basic \fIread\fR\|(2) or \fIwrite\fR\|(2) I/O. \fIfseek\fR\|(2) is used to
246 position the I/O location.
249 Basic \fIpread\fR\|(2) or \fIpwrite\fR\|(2) I/O.
252 Basic \fIreadv\fR\|(2) or \fIwritev\fR\|(2) I/O. Will emulate queuing by
253 coalescing adjacents IOs into a single submission.
256 Linux native asynchronous I/O.
259 glibc POSIX asynchronous I/O using \fIaio_read\fR\|(3) and \fIaio_write\fR\|(3).
262 File is memory mapped with \fImmap\fR\|(2) and data copied using
266 \fIsplice\fR\|(2) is used to transfer the data and \fIvmsplice\fR\|(2) to
267 transfer data from user-space to the kernel.
270 Use the syslet system calls to make regular read/write asynchronous.
273 SCSI generic sg v3 I/O. May be either synchronous using the SG_IO ioctl, or if
274 the target is an sg character device, we use \fIread\fR\|(2) and
275 \fIwrite\fR\|(2) for asynchronous I/O.
278 Doesn't transfer any data, just pretends to. Mainly used to exercise \fBfio\fR
279 itself and for debugging and testing purposes.
282 Transfer over the network. \fBfilename\fR must be set appropriately to
283 `\fIhost\fR/\fIport\fR' regardless of data direction. If receiving, only the
284 \fIport\fR argument is used.
287 Like \fBnet\fR, but uses \fIsplice\fR\|(2) and \fIvmsplice\fR\|(2) to map data
291 Doesn't transfer any data, but burns CPU cycles according to \fBcpuload\fR and
292 \fBcpucycles\fR parameters.
295 The GUASI I/O engine is the Generic Userspace Asynchronous Syscall Interface
296 approach to asycnronous I/O.
298 See <http://www.xmailserver.org/guasi\-lib.html>.
301 Loads an external I/O engine object file. Append the engine filename as
306 .BI iodepth \fR=\fPint
307 Number of I/O units to keep in flight against the file. Default: 1.
309 .BI iodepth_batch \fR=\fPint
310 Number of I/Os to submit at once. Default: \fBiodepth\fR.
312 .BI iodepth_low \fR=\fPint
313 Low watermark indicating when to start filling the queue again. Default:
316 .BI direct \fR=\fPbool
317 If true, use non-buffered I/O (usually O_DIRECT). Default: false.
319 .BI buffered \fR=\fPbool
320 If true, use buffered I/O. This is the opposite of the \fBdirect\fR parameter.
323 .BI offset \fR=\fPint
324 Offset in the file to start I/O. Data before the offset will not be touched.
327 How many I/Os to perform before issuing an \fBfsync\fR\|(2) of dirty data. If
328 0, don't sync. Default: 0.
330 .BI overwrite \fR=\fPbool
331 If writing, setup the file first and do overwrites. Default: false.
333 .BI end_fsync \fR=\fPbool
334 Sync file contents when job exits. Default: false.
336 .BI fsync_on_close \fR=\fPbool
337 If true, sync file contents on close. This differs from \fBend_fsync\fR in that
338 it will happen on every close, not just at the end of the job. Default: false.
340 .BI rwmixcycle \fR=\fPint
341 How many milliseconds before switching between reads and writes for a mixed
342 workload. Default: 500ms.
344 .BI rwmixread \fR=\fPint
345 Percentage of a mixed workload that should be reads. Default: 50.
347 .BI rwmixwrite \fR=\fPint
348 Percentage of a mixed workload that should be writes. If \fBrwmixread\fR and
349 \fBwrmixwrite\fR are given and do not sum to 100%, the latter of the two
350 overrides the first. Default: 50.
353 Normally \fBfio\fR will cover every block of the file when doing random I/O. If
354 this parameter is given, a new offset will be chosen without looking at past
355 I/O history. This parameter is mutually exclusive with \fBverify\fR.
358 Run job with given nice value. See \fInice\fR\|(2).
361 Set I/O priority value of this job between 0 (highest) and 7 (lowest). See
364 .BI prioclass \fR=\fPint
365 Set I/O priority class. See \fIionice\fR\|(1).
367 .BI thinktime \fR=\fPint
368 Stall job for given number of microseconds between issuing I/Os.
370 .BI thinktime_spin \fR=\fPint
371 Pretend to spend CPU time for given number of microseconds, sleeping the rest
372 of the time specified by \fBthinktime\fR. Only valid if \fBthinktime\fR is set.
374 .BI thinktime_blocks \fR=\fPint
375 Number of blocks to issue before waiting \fBthinktime\fR microseconds.
379 Cap bandwidth used by this job to this number of KiB/s.
381 .BI ratemin \fR=\fPint
382 Tell \fBfio\fR to do whatever it can to maintain at least the given bandwidth.
383 Failing to meet this requirement will cause the job to exit.
385 .BI rate_iops \fR=\fPint
386 Cap the bandwidth to this number of IOPS. If \fBblocksize\fR is a range, the
387 smallest block size is used as the metric.
389 .BI rate_iops_min \fR=\fPint
390 If this rate of I/O is not met, the job will exit.
392 .BI ratecycle \fR=\fPint
393 Average bandwidth for \fBrate\fR and \fBratemin\fR over this number of
394 milliseconds. Default: 1000ms.
396 .BI cpumask \fR=\fPint
397 Set CPU affinity for this job. \fIint\fR is a bitmask of allowed CPUs the job
398 may run on. See \fBsched_setaffinity\fR\|(2).
400 .BI cpus_allowed \fR=\fPstr
401 Same as \fBcpumask\fR, but allows a comma-delimited list of CPU numbers.
403 .BI startdelay \fR=\fPint
404 Delay start of job for the specified number of seconds.
406 .BI runtime \fR=\fPint
407 Terminate processing after the specified number of seconds.
410 If given, run for the specified \fBruntime\fR duration even if the files are
411 completely read or written. The same workload will be repeated as many times
412 as \fBruntime\fR allows.
414 .BI ramp_time \fR=\fPint
415 If set, fio will run the specified workload for this amount of time before
416 logging any performance numbers. Useful for letting performance settle before
417 logging results, thus minimizing the runtime required for stable results. Note
418 that the ramp_time is considered lead in time for a job, thus it will increase
419 the total runtime if a special timeout or runtime is specified.
421 .BI invalidate \fR=\fPbool
422 Invalidate buffer-cache for the file prior to starting I/O. Default: true.
425 Use synchronous I/O for buffered writes. For the majority of I/O engines,
426 this means using O_SYNC. Default: false.
428 .BI iomem \fR=\fPstr "\fR,\fP mem" \fR=\fPstr
429 Allocation method for I/O unit buffer. Allowed values are:
434 Allocate memory with \fImalloc\fR\|(3).
437 Use shared memory buffers allocated through \fIshmget\fR\|(2).
440 Same as \fBshm\fR, but use huge pages as backing.
443 Use \fImmap\fR\|(2) for allocation. Uses anonymous memory unless a filename
444 is given after the option in the format `:\fIfile\fR'.
447 Same as \fBmmap\fR, but use huge files as backing.
450 The amount of memory allocated is the maximum allowed \fBblocksize\fR for the
451 job multiplied by \fBiodepth\fR. For \fBshmhuge\fR or \fBmmaphuge\fR to work,
452 the system must have free huge pages allocated. \fBmmaphuge\fR also needs to
453 have hugetlbfs mounted, and \fIfile\fR must point there.
456 .BI hugepage\-size \fR=\fPint
457 Defines the size of a huge page. Must be at least equal to the system setting.
458 Should be a multiple of 1MiB. Default: 4MiB.
461 Terminate all jobs when one finishes. Default: wait for each job to finish.
463 .BI bwavgtime \fR=\fPint
464 Average bandwidth calculations over the given time in milliseconds. Default:
467 .BI create_serialize \fR=\fPbool
468 If true, serialize file creation for the jobs. Default: true.
470 .BI create_fsync \fR=\fPbool
471 \fIfsync\fR\|(2) data file after creation. Default: true.
473 .BI create_on_open \fR=\fPbool
474 If true, the files are not created until they are opened for IO by the job.
476 .BI pre_read \fR=\fPbool
477 If this is given, files will be pre-read into memory before starting the given
478 IO operation. This will also clear the \fR \fBinvalidate\fR flag, since it is
479 pointless to pre-read and then drop the cache.
481 .BI unlink \fR=\fPbool
482 Unlink job files when done. Default: false.
485 Specifies the number of iterations (runs of the same workload) of this job.
488 .BI do_verify \fR=\fPbool
489 Run the verify phase after a write phase. Only valid if \fBverify\fR is set.
492 .BI verify \fR=\fPstr
493 Method of verifying file contents after each iteration of the job. Allowed
498 .B md5 crc16 crc32 crc64 crc7 sha256 sha512
499 Store appropriate checksum in the header of each block.
502 Write extra information about each I/O (timestamp, block number, etc.). The
503 block number is verified.
506 Fill I/O buffers with a specific pattern that is used to verify. The pattern is
507 specified by appending `:\fIint\fR' to the parameter. \fIint\fR cannot be larger
511 Pretend to verify. Used for testing internals.
515 .BI verify_sort \fR=\fPbool
516 If true, written verify blocks are sorted if \fBfio\fR deems it to be faster to
517 read them back in a sorted manner. Default: true.
519 .BI verify_offset \fR=\fPint
520 Swap the verification header with data somewhere else in the block before
521 writing. It is swapped back before verifying.
523 .BI verify_interval \fR=\fPint
524 Write the verification header for this number of bytes, which should divide
525 \fBblocksize\fR. Default: \fBblocksize\fR.
527 .BI verify_fatal \fR=\fPbool
528 If true, exit the job on the first observed verification failure. Default:
532 Wait for preceeding jobs in the job file to exit before starting this one.
533 \fBstonewall\fR implies \fBnew_group\fR.
536 Start a new reporting group. If not given, all jobs in a file will be part
537 of the same reporting group, unless separated by a stonewall.
539 .BI numjobs \fR=\fPint
540 Number of clones (processes/threads performing the same workload) of this job.
544 If set, display per-group reports instead of per-job when \fBnumjobs\fR is
548 Use threads created with \fBpthread_create\fR\|(3) instead of processes created
549 with \fBfork\fR\|(2).
551 .BI zonesize \fR=\fPint
552 Divide file into zones of the specified size in bytes. See \fBzoneskip\fR.
554 .BI zoneskip \fR=\fPint
555 Skip the specified number of bytes when \fBzonesize\fR bytes of data have been
558 .BI write_iolog \fR=\fPstr
559 Write the issued I/O patterns to the specified file.
561 .BI read_iolog \fR=\fPstr
562 Replay the I/O patterns contained in the specified file generated by
563 \fBwrite_iolog\fR, or may be a \fBblktrace\fR binary file.
565 .B write_bw_log \fR=\fPstr
566 If given, write a bandwidth log of the jobs in this job file. Can be used to
567 store data of the bandwidth of the jobs in their lifetime. The included
568 fio_generate_plots script uses gnuplot to turn these text files into nice
569 graphs. See \fBwrite_log_log\fR for behaviour of given filename. For this
570 option, the postfix is _bw.log.
573 Same as \fBwrite_bw_log\fR, but writes I/O completion latencies. If no
574 filename is given with this option, the default filename of "jobname_type.log"
575 is used. Even if the filename is given, fio will still append the type of log.
577 .B disable_clat \fR=\fPbool
578 Disable measurements of completion latency numbers. Useful only for cutting
579 back the number of calls to gettimeofday, as that does impact performance at
580 really high IOPS rates. Note that to really get rid of a large amount of these
581 calls, this option must be used with disable_slat and disable_bw as well.
583 .B disable_slat \fR=\fPbool
584 Disable measurements of submission latency numbers. See \fBdisable_clat\fR.
586 .B disable_bw_measurement \fR=\fPbool
587 Disable measurements of throughput/bandwidth numbers. See \fBdisable_clat\fR.
589 .BI lockmem \fR=\fPint
590 Pin the specified amount of memory with \fBmlock\fR\|(2). Can be used to
591 simulate a smaller amount of memory.
593 .BI exec_prerun \fR=\fPstr
594 Before running the job, execute the specified command with \fBsystem\fR\|(3).
596 .BI exec_postrun \fR=\fPstr
597 Same as \fBexec_prerun\fR, but the command is executed after the job completes.
599 .BI ioscheduler \fR=\fPstr
600 Attempt to switch the device hosting the file to the specified I/O scheduler.
602 .BI cpuload \fR=\fPint
603 If the job is a CPU cycle-eater, attempt to use the specified percentage of
606 .BI cpuchunks \fR=\fPint
607 If the job is a CPU cycle-eater, split the load into cycles of the
608 given time in milliseconds.
610 .BI disk_util \fR=\fPbool
611 Generate disk utilization statistics if the platform supports it. Default: true.
613 .BI gtod_reduce \fR=\fPbool
614 Enable all of the gettimeofday() reducing options (disable_clat, disable_slat,
615 disable_bw) plus reduce precision of the timeout somewhat to really shrink the
616 gettimeofday() call count. With this option enabled, we only do about 0.4% of
617 the gtod() calls we would have done if all time keeping was enabled.
619 .BI gtod_cpu \fR=\fPint
620 Sometimes it's cheaper to dedicate a single thread of execution to just getting
621 the current time. Fio (and databases, for instance) are very intensive on
622 gettimeofday() calls. With this option, you can set one CPU aside for doing
623 nothing but logging current time to a shared memory location. Then the other
624 threads/processes that run IO workloads need only copy that segment, instead of
625 entering the kernel with a gettimeofday() call. The CPU set aside for doing
626 these time calls will be excluded from other uses. Fio will manually clear it
627 from the CPU mask of other jobs.
629 While running, \fBfio\fR will display the status of the created jobs. For
633 Threads: 1: [_r] [24.8% done] [ 13509/ 8334 kb/s] [eta 00h:01m:31s]
636 The characters in the first set of brackets denote the current status of each
637 threads. The possible values are:
643 Setup but not started.
649 Initialized, waiting.
652 Running, doing sequential reads.
655 Running, doing random reads.
658 Running, doing sequential writes.
661 Running, doing random writes.
664 Running, doing mixed sequential reads/writes.
667 Running, doing mixed random reads/writes.
670 Running, currently waiting for \fBfsync\fR\|(2).
673 Running, verifying written data.
676 Exited, not reaped by main thread.
679 Exited, thread reaped.
683 The second set of brackets shows the estimated completion percentage of
684 the current group. The third set shows the read and write I/O rate,
685 respectively. Finally, the estimated run time of the job is displayed.
687 When \fBfio\fR completes (or is interrupted by Ctrl-C), it will show data
688 for each thread, each group of threads, and each disk, in that order.
690 Per-thread statistics first show the threads client number, group-id, and
691 error code. The remaining figures are as follows:
695 Number of megabytes of I/O performed.
698 Average data rate (bandwidth).
704 Submission latency minimum, maximum, average and standard deviation. This is
705 the time it took to submit the I/O.
708 Completion latency minimum, maximum, average and standard deviation. This
709 is the time between submission and completion.
712 Bandwidth minimum, maximum, percentage of aggregate bandwidth received, average
713 and standard deviation.
716 CPU usage statistics. Includes user and system time, number of context switches
717 this thread went through and number of major and minor page faults.
720 Distribution of I/O depths. Each depth includes everything less than (or equal)
721 to it, but greater than the previous depth.
724 Number of read/write requests issued, and number of short read/write requests.
727 Distribution of I/O completion latencies. The numbers follow the same pattern
731 The group statistics show:
736 Number of megabytes I/O performed.
739 Aggregate bandwidth of threads in the group.
742 Minimum average bandwidth a thread saw.
745 Maximum average bandwidth a thread saw.
748 Shortest runtime of threads in the group.
751 Longest runtime of threads in the group.
755 Finally, disk statistics are printed with reads first:
760 Number of I/Os performed by all groups.
763 Number of merges in the I/O scheduler.
766 Number of ticks we kept the disk busy.
769 Total time spent in the disk queue.
776 If the \fB\-\-minimal\fR option is given, the results will be printed in a
777 semicolon-delimited format suitable for scripted use. The fields are:
780 .B jobname, groupid, error
784 .B KiB I/O, bandwidth \fR(KiB/s)\fP, runtime \fR(ms)\fP
788 .B min, max, mean, standard deviation
792 .B min, max, mean, standard deviation
796 .B min, max, aggregate percentage of total, mean, standard deviation
802 .B KiB I/O, bandwidth \fR(KiB/s)\fP, runtime \fR(ms)\fP
806 .B min, max, mean, standard deviation
810 .B min, max, mean, standard deviation
814 .B min, max, aggregate percentage of total, mean, standard deviation
820 .B user, system, context switches, major page faults, minor page faults
823 IO depth distribution:
825 .B <=1, 2, 4, 8, 16, 32, >=64
828 IO latency distribution (ms):
830 .B <=2, 4, 10, 20, 50, 100, 250, 500, 750, 1000, >=2000
837 was written by Jens Axboe <jens.axboe@oracle.com>.
839 This man page was written by Aaron Carroll <aaronc@cse.unsw.edu.au> based
840 on documentation by Jens Axboe.
842 Report bugs to the \fBfio\fR mailing list <fio@vger.kernel.org>.
845 For further documentation see \fBHOWTO\fR and \fBREADME\fR.
847 Sample jobfiles are available in the \fBexamples\fR directory.