X-Git-Url: https://git.kernel.dk/?p=fio.git;a=blobdiff_plain;f=HOWTO;h=3f8acee15221f321a8838fa907759d3d96455e2e;hp=2a4f4d02398b434f43859e879c1e978fef9291be;hb=0228cfe7bb04b3c8329f8e77ee47e30e1a5a03cd;hpb=e0f01317e81e5de963734ba72996790b5adf732d diff --git a/HOWTO b/HOWTO index 2a4f4d02..3f8acee1 100644 --- a/HOWTO +++ b/HOWTO @@ -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 @@ -1062,9 +1066,14 @@ random_generator=str Fio supports the following engines for generating nice=int Run the job with the given nice value. See man nice(2). + On Windows, values less than -15 set the process class to "High"; + -1 through -15 set "Above Normal"; 1 through 15 "Below Normal"; + and above 15 "Idle" priority class. + prio=int Set the io priority value of this job. Linux limits us to a positive value between 0 and 7, with 0 being the highest. - See man ionice(1). + See man ionice(1). Refer to an appropriate manpage for + other operating systems since meaning of priority may differ. prioclass=int Set the io priority class. See man ionice(1). @@ -1170,7 +1179,7 @@ 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. @@ -1220,6 +1229,7 @@ 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). @@ -1289,7 +1299,7 @@ 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. @@ -1328,6 +1338,8 @@ 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. @@ -1546,10 +1558,10 @@ read_iolog=str Open an iolog with the specified file name and replay the replay_no_stall=int When replaying I/O with read_iolog the default behavior is to attempt to respect the time stamps within the log and - replay them with the appropriate delay between IOPS. By + replay them with the appropriate delay between IOPS. By setting this variable fio will not respect the timestamps and attempt to replay them as fast as possible while still - respecting ordering. The result is the same I/O pattern to a + respecting ordering. The result is the same I/O pattern to a given device, but different timings. replay_redirect=str While replaying I/O patterns using read_iolog the @@ -1561,13 +1573,14 @@ replay_redirect=str While replaying I/O patterns using read_iolog the mapping. Replay_redirect causes all IOPS to be replayed onto the single specified device regardless of the device it was recorded from. i.e. replay_redirect=/dev/sdc would cause all - IO in the blktrace to be replayed onto /dev/sdc. This means - multiple devices will be replayed onto a single, if the trace - contains multiple devices. If you want multiple devices to be - replayed concurrently to multiple redirected devices you must - blkparse your trace into separate traces and replay them with - independent fio invocations. Unfortuantely this also breaks - the strict time ordering between multiple device accesses. + IO in the blktrace or iolog to be replayed onto /dev/sdc. + This means multiple devices will be replayed onto a single + device, if the trace contains multiple devices. If you want + multiple devices to be replayed concurrently to multiple + redirected devices you must blkparse your trace into separate + traces and replay them with independent fio invocations. + Unfortuantely this also breaks the strict time ordering + between multiple device accesses. replay_align=int Force alignment of IO offsets and lengths in a trace to this power of 2 value. @@ -1600,10 +1613,18 @@ 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 @@ -1619,6 +1640,20 @@ 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 @@ -1651,6 +1686,10 @@ log_store_compressed=bool If set, fio will store the log files in a the --inflate-log command line parameter. The files will be stored with a .fz suffix. +log_unix_epoch=bool If set, fio will log Unix timestamps to the log + files produced by enabling write_type_log for each log type, instead + of the default zero-based timestamps. + block_error_percentiles=bool If set, record errors in trim block-sized units from writes and trims and output a histogram of how many trims it took to get to errors, and what kind @@ -1834,12 +1873,12 @@ 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. @@ -1921,7 +1960,7 @@ be the starting port number since fio will use a range of ports. [mtd] skip_bad=bool Skip operations against known bad blocks. [libhdfs] hdfsdirectory libhdfs will create chunk in this HDFS directory -[libhdfs] chunck_size the size of the chunck to use for each file. +[libhdfs] chunk_size the size of the chunk to use for each file. 6.0 Interpreting the output