X-Git-Url: https://git.kernel.dk/?p=fio.git;a=blobdiff_plain;f=HOWTO;h=a1b2e8c0bf7a6f51bceb8016618acb32e7dae01e;hp=5e9b390bcf3902ce8f3d4400e102f49ace9f2329;hb=059b080217b86dbf9f3574c4661a1b2300522c79;hpb=21b8aee865f0d3960687ce6ba7385e5977f45061 diff --git a/HOWTO b/HOWTO index 5e9b390b..a1b2e8c0 100644 --- a/HOWTO +++ b/HOWTO @@ -244,6 +244,7 @@ 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. With the above in mind, here follows the complete list of fio job parameters. @@ -318,8 +319,12 @@ rw=str Type of io pattern. Accepted values are: a number of IO's to do before getting a new offset, this is one by appending a ':' to the end of the string given. For a random read, it would look like 'rw=randread:8' for - passing in an offset modifier with a value of 8. See the - 'rw_sequencer' option. + passing in an offset modifier with a value of 8. If the + postfix is used with a sequential IO pattern, then the value + specified will be added to the generated offset for each IO. + For instance, using rw=write:4k will skip 4k for every + write. It turns sequential IO into sequential IO with holes. + See the 'rw_sequencer' option. rw_sequencer=str If an offset modifier is given by appending a number to the rw= line, then this option controls how that @@ -569,9 +574,9 @@ ioengine=str Defines how the job issues io to the file. The following for more info on GUASI. rdma The RDMA I/O engine supports both RDMA - memory semantic(RDMA_WRITE/RDMA_READ) and - channel semantic(Send/Recv) in InfiniBand, RoCE - and iWarp environment. + memory semantics (RDMA_WRITE/RDMA_READ) and + channel semantics (Send/Recv) for the + InfiniBand, RoCE and iWARP protocols. external Prefix to specify loading an external IO engine object file. Append the engine @@ -678,10 +683,10 @@ norandommap Normally fio will cover every block of the file when doing blocksizes (via bsrange=) are used, since fio only tracks complete rewrites of blocks. -softrandommap See norandommap. If fio runs with the random block map enabled - and it fails to allocate the map, if this option is set it - will continue without a random block map. As coverage will - not be as complete as with random maps, this option is +softrandommap=bool See norandommap. If fio runs with the random block map + enabled and it fails to allocate the map, if this option is + set it will continue without a random block map. As coverage + will not be as complete as with random maps, this option is disabled by default. nice=int Run the job with the given nice value. See man nice(2). @@ -992,7 +997,8 @@ verify_backlog_batch=int Control how many blocks fio will verify if verify_backlog_batch is larger than verify_backlog, some blocks will be verified more than once. -stonewall Wait for preceeding jobs in the job file to exit, before +stonewall +wait_for_previous Wait for preceeding jobs in the job file to exit, before starting this one. Can be used to insert serialization points in the job file. A stone wall also implies starting a new reporting group. @@ -1119,6 +1125,18 @@ disable_slat=bool Disable measurements of submission latency numbers. See disable_bw=bool Disable measurements of throughput/bandwidth numbers. See disable_lat. +clat_percentiles=bool Enable the reporting of percentiles of + completion latencies. + +percentile_list=float_list Overwrite the default list of percentiles + for completion latencies. Each number is a floating + number in the range (0,100], and the maximum length of + the list is 20. Use ':' to separate the numbers, and + list the numbers in ascending order. For example, + --percentile_list=99.5:99.9 will cause fio to report + the values of completion latency below which 99.5% and + 99.9% of the observed latencies fell, respectively. + gtod_reduce=bool Enable all of the gettimeofday() reducing options (disable_clat, disable_slat, disable_bw) plus reduce precision of the timeout somewhat to really shrink