X-Git-Url: https://git.kernel.dk/?p=fio.git;a=blobdiff_plain;f=HOWTO;h=f4f596a4c02e7880a0394f809a1f24aae05a6737;hp=6f8f3f4ccf35818610b50de85874d23e6692a23f;hb=fc6bd43c62196441607e6c36ec66bd0e16f9e4ef;hpb=ef67a8a352c5cf6a1a179ad726371ccca43d839f diff --git a/HOWTO b/HOWTO index 6f8f3f4c..f4f596a4 100644 --- a/HOWTO +++ b/HOWTO @@ -197,12 +197,10 @@ Some parameters take an option of a given type, such as an integer or a string. The following types are used: str String. This is a sequence of alpha characters. -int Integer. A whole number value, can be negative. If prefixed with - 0x, the integer is assumed to be of base 16 (hexadecimal). time Integer with possible time postfix. In seconds unless otherwise specified, use eg 10m for 10 minutes. Accepts s/m/h for seconds, minutes, and hours. -siint SI integer. A whole number value, which may contain a postfix +int SI integer. A whole number value, which may contain a postfix describing the base of the number. Accepted postfixes are k/m/g, meaning kilo, mega, and giga. So if you want to specify 4096, you could either write out '4096' or just give 4k. The postfixes @@ -217,7 +215,7 @@ irange Integer range with postfix. Allows value range to be given, such as 1024-4096. A colon may also be used as the separator, eg 1k:4k. If the option allows two sets of ranges, they can be specified with a ',' or '/' delimiter: 1k-4k/8k-32k. Also see - siint. + int. With the above in mind, here follows the complete list of fio job parameters. @@ -302,14 +300,14 @@ fadvise_hint=bool By default, fio will use fadvise() to advise the kernel If set, fio will use POSIX_FADV_SEQUENTIAL for sequential IO and POSIX_FADV_RANDOM for random IO. -size=siint The total size of file io for this job. Fio will run until +size=int The total size of file io for this job. Fio will run until this many bytes has been transferred, unless runtime is limited by other options (such as 'runtime', for instance). Unless specific nr_files and filesize options are given, fio will divide this size between the available files specified by the job. -filesize=siint Individual file sizes. May be a range, in which case fio +filesize=int Individual file sizes. May be a range, in which case fio will select sizes for files at random within the given range and limited to 'size' in total (if that is given). If not given, each created file is the same size. @@ -318,10 +316,10 @@ fill_device=bool Sets size to something really large and waits for ENOSPC (no space left on device) as the terminating condition. Only makes sense with sequential write. -blocksize=siint -bs=siint The block size used for the io units. Defaults to 4k. Values - can be given for both read and writes. If a single siint is - given, it will apply to both. If a second siint is specified +blocksize=int +bs=int The block size used for the io units. Defaults to 4k. Values + can be given for both read and writes. If a single int is + given, it will apply to both. If a second int is specified after a comma, it will apply to writes only. In other words, the format is either bs=read_and_write or bs=read,write. bs=4k,8k will thus use 4k blocks for reads, and 8k blocks @@ -329,6 +327,14 @@ bs=siint The block size used for the io units. Defaults to 4k. Values can do so by passing an empty read size - bs=,8k will set 8k for writes and leave the read default value. +blockalign=int +ba=int At what boundary to align random IO offsets. Defaults to + the same as 'blocksize' the minimum blocksize given. + Minimum alignment is typically 512b for using direct IO, + though it usually depends on the hardware block size. This + option is mutually exclusive with using a random map for + files, so it will turn off that option. + blocksize_range=irange bsrange=irange Instead of giving a single block size, specify a range and fio will mix the issued io block sizes. The issued @@ -361,6 +367,15 @@ bssplit=str Sometimes you want even finer grained control of the always add up to 100, if bssplit is given a range that adds up to more, it will error out. + bssplit also supports giving separate splits to reads and + writes. The format is identical to what bs= accepts. You + have to separate the read and write parts with a comma. So + if you want a workload that has 50% 2k reads and 50% 4k reads, + while having 90% 4k writes and 10% 8k writes, you would + specify: + + bssplit=2k/50:4k/50,4k/90,8k/10 + blocksize_unaligned bs_unaligned If this option is given, any byte size value within bsrange may be used as a block range. This typically wont work with @@ -503,7 +518,7 @@ direct=bool If value is true, use non-buffered io. This is usually buffered=bool If value is true, use buffered io. This is the opposite of the 'direct' option. Defaults to true. -offset=siint Start io at the given offset in the file. The data before +offset=int Start io at the given offset in the file. The data before the given offset will not be touched. This effectively caps the file size at real_size - offset. @@ -673,7 +688,7 @@ mem=str Fio can use various types of memory as the io unit buffer. location should point there. So if it's mounted in /huge, you would use mem=mmaphuge:/huge/somefile. -hugepage-size=siint +hugepage-size=int Defines the size of a huge page. Must at least be equal to the system setting, see /proc/meminfo. Defaults to 4MiB. Should probably always be a multiple of megabytes, so using @@ -758,11 +773,11 @@ verifysort=bool If set, fio will sort written verify blocks when it deems fast IO where the red-black tree sorting CPU time becomes significant. -verify_offset=siint Swap the verification header with data somewhere else +verify_offset=int Swap the verification header with data somewhere else in the block before writing. Its swapped back before verifying. -verify_interval=siint Write the verification header at a finer granularity +verify_interval=int Write the verification header at a finer granularity than the blocksize. It will be written for chunks the size of header_interval. blocksize should divide this evenly. @@ -806,9 +821,9 @@ thread fio defaults to forking jobs, however if this option is given, fio will use pthread_create(3) to create threads instead. -zonesize=siint Divide a file into zones of the specified size. See zoneskip. +zonesize=int Divide a file into zones of the specified size. See zoneskip. -zoneskip=siint Skip the specified number of bytes when zonesize data has +zoneskip=int Skip the specified number of bytes when zonesize data has been read. The two zone options can be used to only do io on zones of a file. @@ -842,7 +857,7 @@ write_lat_log=str Same as write_bw_log, except that this option stores io The actual log names will be foo_clat.log and foo_slat.log. This helps fio_generate_plot fine the logs automatically. -lockmem=siint Pin down the specified amount of memory with mlock(2). Can +lockmem=int Pin down the specified amount of memory with mlock(2). Can potentially be used instead of removing memory or booting with less memory to simulate a smaller amount of memory. @@ -920,7 +935,7 @@ I Thread initialized, waiting. M Running, doing mixed sequential reads/writes. m Running, doing mixed random reads/writes. F Running, currently waiting for fsync() -V Running, doing verification of written data. + V Running, doing verification of written data. E Thread exited, not reaped by main thread yet. _ Thread reaped.