X-Git-Url: https://git.kernel.dk/?p=fio.git;a=blobdiff_plain;f=HOWTO;h=6c674b27d549a28242d0dc77c5b1e5b2d6a1a06a;hp=ab25cb2796ddafeec8b375fe832c61825238fe81;hb=bb49c8bd53e2b3fd7abe31fde742b5f2b1563ef5;hpb=4717fc5db6601707d6e4fe7ea1e383f1847f5620 diff --git a/HOWTO b/HOWTO index ab25cb27..6c674b27 100644 --- a/HOWTO +++ b/HOWTO @@ -297,7 +297,7 @@ irange Integer range with suffix. Allows value range to be given, such 1k:4k. If the option allows two sets of ranges, they can be specified with a ',' or '/' delimiter: 1k-4k/8k-32k. Also see int. -float_list A list of floating numbers, separated by a ':' character. +float_list A list of floating point numbers, separated by a ':' character. With the above in mind, here follows the complete list of fio job parameters. @@ -405,6 +405,7 @@ rw=str Type of io pattern. Accepted values are: trimwrite Mixed trims and writes. Blocks will be trimmed first, then written to. + Fio defaults to read if the option is not specified. For the mixed io types, the default is to split them 50/50. For certain types of io the result may still be skewed a bit, since the speed may be different. It is possible to specify @@ -699,7 +700,8 @@ ioengine=str Defines how the job issues io to the file. The following sync Basic read(2) or write(2) io. lseek(2) is used to position the io location. - psync Basic pread(2) or pwrite(2) io. + psync Basic pread(2) or pwrite(2) io. Default on all + supported operating systems except for Windows. vsync Basic readv(2) or writev(2) IO. @@ -717,6 +719,7 @@ ioengine=str Defines how the job issues io to the file. The following solarisaio Solaris native asynchronous io. windowsaio Windows native asynchronous io. + Default on Windows. mmap File is memory mapped and data copied to/from using memcpy(3). @@ -754,7 +757,8 @@ ioengine=str Defines how the job issues io to the file. The following 85% of the CPU. In case of SMP machines, use numjobs= to get desired CPU usage, as the cpuload only loads a single - CPU at the desired rate. + CPU at the desired rate. A job never finishes + unless there is at least one non-cpuio job. guasi The GUASI IO engine is the Generic Userspace Asyncronous Syscall Interface approach @@ -1171,7 +1175,7 @@ cpus_allowed_policy=str Set the policy of how fio distributes the CPUs one cpu per job. If not enough CPUs are given for the jobs listed, then fio will roundrobin the CPUs in the set. -numa_cpu_nodes=str Set this job running on spcified NUMA nodes' CPUs. The +numa_cpu_nodes=str Set this job running on specified NUMA nodes' CPUs. The arguments allow comma delimited list of cpu numbers, A-B ranges, or 'all'. Note, to enable numa options support, fio must be built on a system with libnuma-dev(el) installed. @@ -1210,6 +1214,48 @@ ramp_time=time If set, fio will run the specified workload for this amount thus it will increase the total runtime if a special timeout or runtime is specified. +steadystate=str:float +ss=str:float Define the criterion and limit for assessing steady state + performance. The first parameter designates the criterion + whereas the second parameter sets the threshold. When the + criterion falls below the threshold for the specified duration, + the job will stop. For example, iops_slope:0.1% will direct fio + to terminate the job when the least squares regression slope + falls below 0.1% of the mean IOPS. If group_reporting is + enabled this will apply to all jobs in the group. Below is the + list of available steady state assessment criteria. All + assessments are carried out using only data from the rolling + collection window. Threshold limits can be expressed as a fixed + value or as a percentage of the mean in the collection window. + iops Collect IOPS data. Stop the job if all + individual IOPS measurements are within the + specified limit of the mean IOPS (e.g., iops:2 + means that all individual IOPS values must be + within 2 of the mean, whereas iops:0.2% means + that all individual IOPS values must be within + 0.2% of the mean IOPS to terminate the job). + iops_slope + Collect IOPS data and calculate the least + squares regression slope. Stop the job if the + slope falls below the specified limit. + bw Collect bandwidth data. Stop the job if all + individual bandwidth measurements are within + the specified limit of the mean bandwidth. + bw_slope + Collect bandwidth data and calculate the least + squares regression slope. Stop the job if the + slope falls below the specified limit. + +steadystate_duration=time +ss_dur=time A rolling window of this duration will be used to judge whether + steady state has been reached. Data will be collected once per + second. The default is 0 which disables steady state detection. + +steadystate_ramp_time=time +ss_ramp=time Allow the job to run for the specified duration before + beginning data collection for checking the steady state job + termination criterion. The default is 0. + invalidate=bool Invalidate the buffer/page cache parts for this file prior to starting io. Defaults to true. @@ -1221,6 +1267,7 @@ mem=str Fio can use various types of memory as the io unit buffer. The allowed values are: malloc Use memory from malloc(3) as the buffers. + Default memory type. shm Use shared memory as the buffers. Allocated through shmget(2). @@ -1290,7 +1337,7 @@ iopsavgtime=int Average the calculated IOPS over the given time. Value through 'write_iops_log', then the minimum of this option and 'log_avg_msec' will be used. Default: 500ms. -create_serialize=bool If true, serialize the file creating for the jobs. +create_serialize=bool If true, serialize the file creation for the jobs. This may be handy to avoid interleaving of data files, which may greatly depend on the filesystem used and even the number of processors in the system. @@ -1329,6 +1376,8 @@ unlink=bool Unlink the job files when done. Not the default, as repeated runs of that job would then waste time recreating the file set again and again. +unlink_each_loop=bool Unlink job files after each iteration or loop. + loops=int Run the specified number of iterations of this job. Used to repeat the same workload a given number of times. Defaults to 1. @@ -1601,10 +1650,18 @@ 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. If 'per_job_logs' is false, then + find the logs automatically. If 'per_job_logs' is false, then the filename will not include the job index. See 'Log File Formats'. +write_hist_log=str Same as write_lat_log, but writes I/O completion + latency histograms. If no filename is given with this option, the + default filename of "jobname_clat_hist.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. + If per_job_logs is false, then the filename will not include the + job index. See 'Log File Formats'. + 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 @@ -1620,6 +1677,20 @@ log_avg_msec=int By default, fio will log an entry in the iops, latency, specified period of time, reducing the resolution of the log. See log_max_value as well. Defaults to 0, logging all entries. +log_hist_msec=int Same as log_avg_msec, but logs entries for completion + latency histograms. Computing latency percentiles from averages of + intervals using log_avg_msec is innacurate. Setting this option makes + fio log histogram entries over the specified period of time, reducing + log sizes for high IOPS devices while retaining percentile accuracy. + See log_hist_coarseness as well. Defaults to 0, meaning histogram + logging is disabled. + +log_hist_coarseness=int Integer ranging from 0 to 6, defining the coarseness + of the resolution of the histogram logs enabled with log_hist_msec. For + each increment in coarseness, fio outputs half as many bins. Defaults to + 0, for which histogram logs contain 1216 latency bins. See + 'Log File Formats'. + log_max_value=bool If log_avg_msec is set, fio logs the average over that window. If you instead want to log the maximum value, set this option to 1. Defaults to 0, meaning that averaged values are @@ -1835,12 +1906,12 @@ that defines them is selected. [psyncv2] hipri Set RWF_HIPRI on IO, indicating to the kernel that it's of higher priority than normal. -[cpu] cpuload=int Attempt to use the specified percentage of CPU cycles. +[cpuio] cpuload=int Attempt to use the specified percentage of CPU cycles. -[cpu] cpuchunks=int Split the load into cycles of the given time. In +[cpuio] cpuchunks=int Split the load into cycles of the given time. In microseconds. -[cpu] exit_on_io_done=bool Detect when IO threads are done, then exit. +[cpuio] exit_on_io_done=bool Detect when IO threads are done, then exit. [netsplice] hostname=str [net] hostname=str The host name or IP address to use for TCP or UDP based IO.