X-Git-Url: https://git.kernel.dk/?p=fio.git;a=blobdiff_plain;f=HOWTO;h=6952c84e84b141fb81b6c649ec0fb054d8bcc248;hp=b823eaed24a5b84b30bbf2d19ab5f4ef9f089ae0;hb=5c4ef02e212df7cc536680ac44dd01f34bfb74a2;hpb=d86ae56c2995f90b5ac38de981d6f46114dabdf3 diff --git a/HOWTO b/HOWTO index b823eaed..6952c84e 100644 --- a/HOWTO +++ b/HOWTO @@ -10,6 +10,9 @@ Table of contents 7. Terse output 8. Trace file format 9. CPU idleness profiling +10. Verification and triggers +11. Log File Formats + 1.0 Overview and history ------------------------ @@ -198,7 +201,7 @@ 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 @@ -305,6 +308,16 @@ name=str ASCII name of the job. This may be used to override the special purpose of also signaling the start of a new job. +wait_for=str Specifies the name of the already defined job to wait + for. Single waitee name only may be specified. If set, the job + won't be started until all workers of the waitee job are done. + + Wait_for operates on the job name basis, so there are a few + limitations. First, the waitee must be defined prior to the + waiter job (meaning no forward references). Second, if a job + is being referenced as a waitee, it must have a unique name + (no duplicate waitees). + description=str Text description of the job. Doesn't do anything except dump this text description when this job is run. It's not parsed. @@ -623,7 +636,16 @@ buffer_pattern=str If set, fio will fill the io buffers with this the other options related to buffer contents. The setting can be any pattern of bytes, and can be prefixed with 0x for hex values. It may also be a string, where the string must then - be wrapped with "". + be wrapped with "", e.g.: + + buffer_pattern="abcd" + or + buffer_pattern=-12 + or + buffer_pattern=0xdeadface + + Also you can combine everything together in any order: + buffer_pattern=0xdeadface"abcd"-12 dedupe_percentage=int If set, fio will generate this percentage of identical buffers when writing. These buffers will be @@ -758,20 +780,14 @@ ioengine=str Defines how the job issues io to the file. The following defines engine specific options. libhdfs Read and write through Hadoop (HDFS). - The 'filename' option is used to specify host, - port of the hdfs name-node to connect. This - engine interprets offsets a little + This engine interprets offsets a little differently. In HDFS, files once created cannot be modified. So random writes are not possible. To imitate this, libhdfs engine - expects bunch of small files to be created - over HDFS, and engine will randomly pick a - file out of those files based on the offset - generated by fio backend. (see the example - job file to create such files, use rw=write - option). Please note, you might want to set - necessary environment variables to work with - hdfs/libhdfs properly. + creates bunch of small files, and engine will + pick a file out of those files based on the + offset enerated by fio backend. Each jobs uses + it's own connection to HDFS. mtd Read, write and erase an MTD character device (e.g., /dev/mtd0). Discards are treated as @@ -782,6 +798,9 @@ ioengine=str Defines how the job issues io to the file. The following overwriting. The writetrim mode works well for this constraint. + pmemblk Read and write through the NVML libpmemblk + interface. + external Prefix to specify loading an external IO engine object file. Append the engine filename, eg ioengine=external:/tmp/foo.o @@ -803,8 +822,10 @@ iodepth_batch_submit=int iodepth_batch=int This defines how many pieces of IO to submit at once. It defaults to 1 which means that we submit each IO as soon as it is available, but can be raised to submit - bigger batches of IO at the time. + bigger batches of IO at the time. If it is set to 0 the iodepth + value will be used. +iodepth_batch_complete_min=int iodepth_batch_complete=int This defines how many pieces of IO to retrieve at once. It defaults to 1 which means that we'll ask for a minimum of 1 IO in the retrieval process from @@ -814,6 +835,31 @@ iodepth_batch_complete=int This defines how many pieces of IO to retrieve events before queuing more IO. This helps reduce IO latency, at the cost of more retrieval system calls. +iodepth_batch_complete_max=int This defines maximum pieces of IO to + retrieve at once. This variable should be used along with + iodepth_batch_complete_min=int variable, specifying the range + of min and max amount of IO which should be retrieved. By default + it is equal to iodepth_batch_complete_min value. + + Example #1: + + iodepth_batch_complete_min=1 + iodepth_batch_complete_max= + + which means that we will retrieve at leat 1 IO and up to the + whole submitted queue depth. If none of IO has been completed + yet, we will wait. + + Example #2: + + iodepth_batch_complete_min=0 + iodepth_batch_complete_max= + + which means that we can retrieve up to the whole submitted + queue depth, but if none of IO has been completed yet, we will + NOT wait and immediately exit the system call. In this example + we simply do polling. + iodepth_low=int The low water mark indicating when to start filling the queue again. Defaults to the same as iodepth, meaning that fio will attempt to keep the queue full at all times. @@ -875,8 +921,8 @@ 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 @@ -922,6 +968,8 @@ random_distribution=str:float By default, fio will use a completely uniform random Uniform random distribution zipf Zipf distribution pareto Pareto distribution + gauss Normal (guassian) distribution + zoned Zoned random distribution When using a zipf or pareto distribution, an input value is also needed to define the access pattern. For zipf, this @@ -930,7 +978,28 @@ random_distribution=str:float By default, fio will use a completely uniform what the given input values will yield in terms of hit rates. If you wanted to use zipf with a theta of 1.2, you would use random_distribution=zipf:1.2 as the option. If a non-uniform - model is used, fio will disable use of the random map. + model is used, fio will disable use of the random map. For + the gauss distribution, a normal deviation is supplied as + a value between 0 and 100. + + For a zoned distribution, fio supports specifying percentages + of IO access that should fall within what range of the file or + device. For example, given a criteria of: + + 60% of accesses should be to the first 10% + 30% of accesses should be to the next 20% + 8% of accesses should be to to the next 30% + 2% of accesses should be to the next 40% + + we can define that through zoning of the random accesses. For + the above example, the user would do: + + random_distribution=zoned:60/10:30/20:8/30:2/40 + + similarly to how bssplit works for setting ranges and + percentages of block sizes. Like bssplit, it's possible to + specify separate zones for reads, writes, and trims. If just + one set is given, it'll apply to all of them. percentage_random=int For a random workload, set how big a percentage should be random. This defaults to 100%, in which case the workload @@ -973,7 +1042,9 @@ random_generator=str Fio supports the following engines for generating typically good enough. LFSR only works with single block sizes, not with workloads that use multiple block sizes. If used with such a workload, fio may read or write - some blocks multiple times. + some blocks multiple times. The default value is tausworthe, + unless the required space exceeds 2^32 blocks. If it does, + then tausworthe64 is selected automatically. nice=int Run the job with the given nice value. See man nice(2). @@ -1013,7 +1084,7 @@ rate=int Cap the bandwidth used by this job. The number is in bytes/sec, will only limit writes (to 500KB/sec), the latter will only limit reads. -ratemin=int Tell fio to do whatever it can to maintain at least this +rate_min=int Tell fio to do whatever it can to maintain at least this bandwidth. Failing to meet this requirement, will cause the job to exit. The same format as rate is used for read vs write separation. @@ -1028,6 +1099,15 @@ rate_iops_min=int If fio doesn't meet this rate of IO, it will cause the job to exit. The same format as rate is used for read vs write separation. +rate_process=str This option controls how fio manages rated IO + submissions. The default is 'linear', which submits IO in a + linear fashion with fixed delays between IOs that gets + adjusted based on IO completion rates. If this is set to + 'poisson', fio will submit IO based on a more real world + random request flow, known as the Poisson process + (https://en.wikipedia.org/wiki/Poisson_process). The lambda + will be 10^6 / IOPS for the given workload. + latency_target=int If set, fio will attempt to find the max performance point that the given workload will run at while maintaining a latency below this target. The values is given in microseconds. @@ -1045,7 +1125,7 @@ latency_percentile=float The percentage of IOs that must fall within the max_latency=int If set, fio will exit the job if it exceeds this maximum latency. It will exit with an ETIME error. -ratecycle=int Average bandwidth for 'rate' and 'ratemin' over this number +rate_cycle=int Average bandwidth for 'rate' and 'rate_min' over this number of milliseconds. cpumask=int Set the CPU affinity of this job. The parameter given is a @@ -1141,6 +1221,9 @@ mem=str Fio can use various types of memory as the io unit buffer. backing. Append filename after mmaphuge, ala mem=mmaphuge:/hugetlbfs/file + mmapshared Same as mmap, but use a MMAP_SHARED + mapping. + The area allocated is a function of the maximum allowed bs size for the job, multiplied by the io depth given. Note that for shmhuge and mmaphuge to work, the system must have @@ -1179,6 +1262,9 @@ exitall When one job finishes, terminate the rest. The default is to wait for each job to finish, sometimes that is not the desired action. +exitall_on_error When one job finishes in error, terminate the rest. The + default is to wait for each job to finish. + bwavgtime=int Average the calculated bandwidth over the given time. Value is specified in milliseconds. @@ -1239,7 +1325,12 @@ do_verify=bool Run the verify phase after a write phase. Only makes sense if verify is set. Defaults to 1. verify=str If writing to a file, fio can verify the file contents - after each iteration of the job. The allowed values are: + after each iteration of the job. Each verification method also implies + verification of special header, which is written to the beginning of + each block. This header also includes meta information, like offset + of the block, block number, timestamp when block was written, etc. + verify=str can be combined with verify_pattern=str option. + The allowed values are: md5 Use an md5 sum of the data area and store it in the header of each block. @@ -1275,11 +1366,11 @@ verify=str If writing to a file, fio can verify the file contents sha1 Use optimized sha1 as the checksum function. - meta Write extra information about each io - (timestamp, block number etc.). The block - number is verified. The io sequence number is - verified for workloads that write data. - See also verify_pattern. + meta This option is deprecated, since now meta information is + included in generic verification header and meta verification + happens by default. For detailed information see the description + of the verify=str setting. This option is kept because of + compatibility's sake with old configurations. Do not use it. pattern Verify a strict pattern. Normally fio includes a header with some basic information and @@ -1324,7 +1415,14 @@ verify_pattern=str If set, fio will fill the io buffers with this buffer at the time(it can be either a decimal or a hex number). The verify_pattern if larger than a 32-bit quantity has to be a hex number that starts with either "0x" or "0X". Use - with verify=meta. + with verify=str. Also, verify_pattern supports %o format, + which means that for each block offset will be written and + then verifyied back, e.g.: + + verify_pattern=%o + + Or use combination of everything: + verify_pattern=0xff%o"abcd"-12 verify_fatal=bool Normally fio will keep checking the entire contents before quitting on a block verification failure. If this @@ -1471,7 +1569,7 @@ write_bw_log=str If given, write a bandwidth log of the jobs in this job 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). If 'per_job_logs' is false, then the filename will not - include the job index. + include the job index. See 'Log File Formats'. write_lat_log=str Same as write_bw_log, except that this option stores io submission, completion, and total latencies instead. If no @@ -1485,8 +1583,8 @@ write_lat_log=str Same as write_bw_log, except that this option stores io 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 - the filename will not include the job index. - + 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 @@ -1494,14 +1592,19 @@ write_iops_log=str Same as write_bw_log, but writes IOPS. If no filename is (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. + the job index. See 'Log File Formats'. 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 disk log, that can quickly grow to a very large size. Setting this option makes fio average the each log entry over the specified period of time, reducing the resolution of the log. - Defaults to 0. + See log_max_value as well. Defaults to 0, logging all entries. + +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 + logged. log_offset=int If this is set, the iolog options will include the byte offset for the IO entry as well as the other data values. @@ -1520,11 +1623,15 @@ log_compression=int If this is set, fio will compress the IO logs as in the specified log file. This feature depends on the availability of zlib. -log_store_compressed=bool If set, and log_compression is also set, - fio will store the log files in a compressed format. They - can be decompressed with fio, using the --inflate-log - command line parameter. The files will be stored with a - .fz suffix. +log_compression_cpus=str Define the set of CPUs that are allowed to + handle online log compression for the IO jobs. This can + provide better isolation between performance sensitive jobs, + and background compression work. + +log_store_compressed=bool If set, fio will store the log files in a + compressed format. They can be decompressed with fio, using + the --inflate-log command line parameter. The files will be + stored with a .fz suffix. block_error_percentiles=bool If set, record errors in trim block-sized units from writes and trims and output a histogram of @@ -1706,6 +1813,9 @@ that defines them is selected. enabled when polling for a minimum of 0 events (eg when iodepth_batch_complete=0). +[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. [cpu] cpuchunks=int Split the load into cycles of the given time. In @@ -1718,11 +1828,13 @@ that defines them is selected. If the job is a TCP listener or UDP reader, the hostname is not used and must be omitted unless it is a valid UDP multicast address. +[libhdfs] namenode=str The host name or IP address of a HDFS cluster namenode to contact. [netsplice] port=int [net] port=int The TCP or UDP port to bind to or connect to. If this is used with numjobs to spawn multiple instances of the same job type, then this will be the starting port number since fio will use a range of ports. +[libhdfs] port=int the listening port of the HFDS cluster namenode. [netsplice] interface=str [net] interface=str The IP address of the network interface used to send or @@ -1779,8 +1891,20 @@ be the starting port number since fio will use a range of ports. 1 : allocate space immidietly inside defragment event, and free right after event +[rbd] clustername=str Specifies the name of the Ceph cluster. +[rbd] rbdname=str Specifies the name of the RBD. +[rbd] pool=str Specifies the naem of the Ceph pool containing RBD. +[rbd] clientname=str Specifies the username (without the 'client.' prefix) + used to access the Ceph cluster. If the clustername is + specified, the clientmae shall be the full type.id + string. If no type. prefix is given, fio will add + 'client.' by default. + [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. + 6.0 Interpreting the output --------------------------- @@ -1876,7 +2000,9 @@ runt= The runtime of that thread cpu= CPU usage. User and system time, along with the number of context switches this thread went through, usage of system and user time, and finally the number of major - and minor page faults. + and minor page faults. The CPU utilization numbers are + averages for the jobs in that reporting group, while the + context and fault counters are summed. IO depths= The distribution of io depths over the job life time. The numbers are divided into powers of 2, so for example the 16= entries includes depths up to that value but higher @@ -2137,10 +2263,43 @@ localbox$ fio --client=server --trigger-file=/tmp/my-trigger --trigger="ipmi-reb For this case, fio would wait for the server to send us the write state, then execute 'ipmi-reboot server' when that happened. -10.1 Loading verify state +10.2 Loading verify state ------------------------- To load store write state, read verification job file must contain the verify_state_load option. If that is set, fio will load the previously stored state. For a local fio run this is done by loading the files directly, and on a client/server run, the server backend will ask the client to send the files over and load them from there. + + +11.0 Log File Formats +--------------------- + +Fio supports a variety of log file formats, for logging latencies, bandwidth, +and IOPS. The logs share a common format, which looks like this: + +time (msec), value, data direction, offset + +Time for the log entry is always in milliseconds. The value logged depends +on the type of log, it will be one of the following: + + Latency log Value is latency in usecs + Bandwidth log Value is in KB/sec + IOPS log Value is IOPS + +Data direction is one of the following: + + 0 IO is a READ + 1 IO is a WRITE + 2 IO is a TRIM + +The offset is the offset, in bytes, from the start of the file, for that +particular IO. The logging of the offset can be toggled with 'log_offset'. + +If windowed logging is enabled though 'log_avg_msec', then fio doesn't log +individual IOs. Instead of logs the average values over the specified +period of time. Since 'data direction' and 'offset' are per-IO values, +they aren't applicable if windowed logging is enabled. If windowed logging +is enabled and 'log_max_value' is set, then fio logs maximum values in +that window instead of averages. +