X-Git-Url: https://git.kernel.dk/?a=blobdiff_plain;f=HOWTO;h=b61a638907334bdc7d8f84e77d2a23d979d69c54;hb=e155cb64ad042af42aafef26d1decf29c03e85d4;hp=0808cc3a07e0f53a62c3476b6789f47426917829;hpb=0c63576e14bc606f81441f20e58a5b6338a5e2d6;p=fio.git diff --git a/HOWTO b/HOWTO index 0808cc3a..b61a6389 100644 --- a/HOWTO +++ b/HOWTO @@ -198,7 +198,7 @@ sections. ------------------------- fio also supports environment variable expansion in job files. Any -substring of the form "${VARNAME}" as part of an option value (in other +sub-string of the form "${VARNAME}" as part of an option value (in other words, on the right of the `='), will be expanded to the value of the environment variable called VARNAME. If no such environment variable is defined, or VARNAME is the empty string, the empty string will be @@ -435,6 +435,7 @@ unified_rw_reporting=bool Fio normally reports statistics on a per randrepeat=bool For random IO workloads, seed the generator in a predictable way so that results are repeatable across repetitions. + Defaults to true. randseed=int Seed the random number generators based on this seed value, to be able to control what sequence of output is being generated. @@ -874,8 +875,8 @@ fsync=int If writing to a file, issue a sync of the dirty data fdatasync=int Like fsync= but uses fdatasync() to only sync data and not metadata blocks. - In FreeBSD and Windows there is no fdatasync(), this falls back to - using fsync() + In FreeBSD and Windows there is no fdatasync(), this falls back + to using fsync() sync_file_range=str:val Use sync_file_range() for every 'val' number of write operations. Fio will track range of writes that @@ -960,6 +961,8 @@ random_generator=str Fio supports the following engines for generating tausworthe Strong 2^88 cycle random number generator lfsr Linear feedback shift register generator + tausworthe64 Strong 64-bit 2^258 cycle random number + generator Tausworthe is a strong random number generator, but it requires tracking on the side if we want to ensure that @@ -1198,6 +1201,17 @@ create_only=bool If true, fio will only run the setup phase of the job. that will be done. The actual job contents are not executed. +allow_file_create=bool If true, fio is permitted to create files as part + of its workload. This is the default behavior. If this + option is false, then fio will error out if the files it + needs to use don't already exist. Default: true. + +allow_mounted_write=bool If this isn't set, fio will abort jobs that + are destructive (eg that write) to what appears to be a + mounted device or partition. This should help catch creating + inadvertently destructive tests, not realizing that the test + will destroy data on the mounted file system. Default: false. + pre_read=bool If this is given, files will be pre-read into memory before starting the given IO operation. This will also clear the 'invalidate' flag, since it is pointless to pre-read @@ -1267,6 +1281,12 @@ verify=str If writing to a file, fio can verify the file contents verified for workloads that write data. See also verify_pattern. + pattern Verify a strict pattern. Normally fio includes + a header with some basic information and + checksumming, but if this option is set, only + the specific pattern set with 'verify_pattern' + is verified. + null Only pretend to verify. Useful for testing internals with ioengine=null, not for much else. @@ -1439,6 +1459,10 @@ replay_align=int Force alignment of IO offsets and lengths in a trace replay_scale=int Scale sector offsets down by this factor when replaying traces. +per_job_logs=bool If set, this generates bw/clat/iops log with per + file private filenames. If not set, jobs with identical names + will share the log filename. Default: true. + write_bw_log=str If given, write a bandwidth log of the jobs in this job file. Can be used to store data of the bandwidth of the jobs in their lifetime. The included fio_generate_plots @@ -1446,7 +1470,8 @@ write_bw_log=str If given, write a bandwidth log of the jobs in this job graphs. See write_lat_log for behaviour of given filename. For this option, the suffix is _bw.x.log, where x is the index of the job (1..N, where N is the number of - jobs). + jobs). If 'per_job_logs' is false, then the filename will not + include the job index. write_lat_log=str Same as write_bw_log, except that this option stores io submission, completion, and total latencies instead. If no @@ -1459,13 +1484,17 @@ write_lat_log=str Same as write_bw_log, except that this option stores io The actual log names will be foo_slat.x.log, foo_clat.x.log, and foo_lat.x.log, where x is the index of the job (1..N, where N is the number of jobs). This helps fio_generate_plot - fine the logs automatically. + fine the logs automatically. If 'per_job_logs' is false, then + the filename will not include the job index. + write_iops_log=str Same as write_bw_log, but writes IOPS. If no filename is given with this option, the default filename of "jobname_type.x.log" is used,where x is the index of the job (1..N, where N is the number of jobs). Even if the filename - is given, fio will still append the type of log. + is given, fio will still append the type of log. If + 'per_job_logs' is false, then the filename will not include + the job index. log_avg_msec=int By default, fio will log an entry in the iops, latency, or bw log for every IO that completes. When writing to the @@ -1927,18 +1956,18 @@ Split up, the format is as follows: terse version, fio version, jobname, groupid, error READ status: Total IO (KB), bandwidth (KB/sec), IOPS, runtime (msec) - Submission latency: min, max, mean, deviation (usec) - Completion latency: min, max, mean, deviation (usec) + Submission latency: min, max, mean, stdev (usec) + Completion latency: min, max, mean, stdev (usec) Completion latency percentiles: 20 fields (see below) - Total latency: min, max, mean, deviation (usec) - Bw (KB/s): min, max, aggregate percentage of total, mean, deviation + Total latency: min, max, mean, stdev (usec) + Bw (KB/s): min, max, aggregate percentage of total, mean, stdev WRITE status: Total IO (KB), bandwidth (KB/sec), IOPS, runtime (msec) - Submission latency: min, max, mean, deviation (usec) - Completion latency: min, max, mean, deviation (usec) + Submission latency: min, max, mean, stdev (usec) + Completion latency: min, max, mean, stdev(usec) Completion latency percentiles: 20 fields (see below) - Total latency: min, max, mean, deviation (usec) - Bw (KB/s): min, max, aggregate percentage of total, mean, deviation + Total latency: min, max, mean, stdev (usec) + Bw (KB/s): min, max, aggregate percentage of total, mean, stdev CPU usage: user, system, context switches, major faults, minor faults IO depths: <=1, 2, 4, 8, 16, 32, >=64 IO latencies microseconds: <=2, 4, 10, 20, 50, 100, 250, 500, 750, 1000