X-Git-Url: https://git.kernel.dk/?p=fio.git;a=blobdiff_plain;f=HOWTO;h=6e052f532a0963c0d3710bb626f59696d60e2f9b;hp=482d69651c0362c3afd5863512dc32f7d73f3733;hb=bb7816439c44f6f98debd8afd167da14d612574c;hpb=a3f001f5f679ae4efc5f34f682b16a2673ec2bac diff --git a/HOWTO b/HOWTO index 482d6965..6e052f53 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 ------------------------ @@ -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. @@ -952,6 +965,8 @@ 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 @@ -960,7 +975,28 @@ 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 @@ -1003,7 +1039,9 @@ 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). @@ -1528,7 +1566,7 @@ 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 @@ -1542,8 +1580,8 @@ 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 @@ -1551,15 +1589,19 @@ 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 as well. Defaults to 0, logging all entries. +log_max=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. @@ -1767,6 +1809,9 @@ 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 @@ -1942,7 +1987,9 @@ 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 @@ -2203,10 +2250,43 @@ 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. +