X-Git-Url: https://git.kernel.dk/?p=fio.git;a=blobdiff_plain;f=HOWTO;h=662689ef304da064f677bdf5bf62b408e604abf3;hp=c6304a7ca2ed7bf27b65df9ce844efa88f221534;hb=a5e371a61c9e37a2389f7473d65e35b29dec1ccd;hpb=b8bc8cba9512c6dce4891fda86de675053605ca2 diff --git a/HOWTO b/HOWTO index c6304a7c..662689ef 100644 --- a/HOWTO +++ b/HOWTO @@ -310,7 +310,7 @@ rw=str Type of io pattern. Accepted values are: write Sequential writes randwrite Random writes randread Random reads - rw Sequential mixed reads and writes + rw,readwrite Sequential mixed reads and writes randrw Random mixed reads and writes For the mixed io types, the default is to split them 50/50. @@ -488,6 +488,22 @@ scramble_buffers=bool If refill_buffers is too costly and the target is block compression attempts, but it will stop naive dedupe of blocks. Default: true. +buffer_compress_percentage=int If this is set, then fio will attempt to + provide IO buffer content (on WRITEs) that compress to + the specified level. Fio does this by providing a mix of + random data and zeroes. Note that this is per block size + unit, for file/disk wide compression level that matches + this setting, you'll also want to set refill_buffers. + +buffer_compress_chunk=int See buffer_compress_percentage. This + setting allows fio to manage how big the ranges of random + data and zeroed data is. Without this set, fio will + provide buffer_compress_percentage of blocksize random + data, followed by the remaining zeroed. With this set + to some chunk size smaller than the block size, fio can + alternate random and zeroed data throughout the IO + buffer. + nrfiles=int Number of files to use for this job. Defaults to 1. openfiles=int Number of files to keep open at the same time. Defaults to @@ -627,6 +643,7 @@ iodepth_low=int The low water mark indicating when to start filling direct=bool If value is true, use non-buffered io. This is usually O_DIRECT. Note that ZFS on Solaris doesn't support direct io. + On Windows the synchronous ioengines don't support direct io. buffered=bool If value is true, use buffered io. This is the opposite of the 'direct' option. Defaults to true. @@ -635,6 +652,13 @@ 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. +offset_increment=int If this is provided, then the real offset becomes + the offset + offset_increment * thread_number, where the + thread number is a counter that starts at 0 and is incremented + for each job. This option is useful if there are several jobs + which are intended to operate on a file in parallel in disjoint + segments, with even spacing between the starting points. + fsync=int If writing to a file, issue a sync of the dirty data for every number of blocks given. For example, if you give 32 as a parameter, fio will sync the file for every 32 @@ -644,7 +668,7 @@ 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 there is no fdatasync(), this falls back to + 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 @@ -1231,6 +1255,25 @@ uid=int Instead of running as the invoking user, set the user ID to gid=int Set group ID, see uid. +flow_id=int The ID of the flow. If not specified, it defaults to being a + global flow. See flow. + +flow=int Weight in token-based flow control. If this value is used, then + there is a 'flow counter' which is used to regulate the + proportion of activity between two or more jobs. fio attempts + to keep this flow counter near zero. The 'flow' parameter + stands for how much should be added or subtracted to the flow + counter on each iteration of the main I/O loop. That is, if + one job has flow=8 and another job has flow=-1, then there + will be a roughly 1:8 ratio in how much one runs vs the other. + +flow_watermark=int The maximum value that the absolute value of the flow + counter is allowed to reach before the job must wait for a + lower value of the counter. + +flow_sleep=int The period of time, in microseconds, to wait after the flow + watermark has been exceeded before retrying operations + In addition, there are some parameters which are only valid when a specific ioengine is in use. These are used identically to normal parameters, with the caveat that when used on the command line, they must come after the ioengine @@ -1296,13 +1339,17 @@ I Thread initialized, waiting. F Running, currently waiting for fsync() V Running, doing verification of written data. E Thread exited, not reaped by main thread yet. -_ Thread reaped. +_ Thread reaped, or +X Thread reaped, exited with an error. +K Thread reaped, exited due to signal. The other values are fairly self explanatory - number of threads currently running and doing io, rate of io since last check (read speed listed first, then write speed), and the estimated completion percentage and time for the running group. It's impossible to estimate runtime of -the following groups (if any). +the following groups (if any). Note that the string is displayed in order, +so it's possible to tell which of the jobs are currently doing what. The +first character is the first job defined in the job file, and so forth. When fio is done (or interrupted by ctrl-c), it will show the data for each thread, group of threads, and disks in that order. For each data @@ -1423,17 +1470,17 @@ Split up, the format is as follows: terse version, fio version, jobname, groupid, error READ status: Total IO (KB), bandwidth (KB/sec), IOPS, runtime (msec) - Submission latency: min, max, mean, deviation - Completion latency: min, max, mean, deviation + Submission latency: min, max, mean, deviation (usec) + Completion latency: min, max, mean, deviation (usec) Completion latency percentiles: 20 fields (see below) - Total latency: min, max, mean, deviation + Total latency: min, max, mean, deviation (usec) Bw: min, max, aggregate percentage of total, mean, deviation WRITE status: Total IO (KB), bandwidth (KB/sec), IOPS, runtime (msec) - Submission latency: min, max, mean, deviation - Completion latency: min, max, mean, deviation + Submission latency: min, max, mean, deviation (usec) + Completion latency: min, max, mean, deviation (usec) Completion latency percentiles: 20 fields (see below) - Total latency: min, max, mean, deviation + Total latency: min, max, mean, deviation (usec) Bw: min, max, aggregate percentage of total, mean, deviation CPU usage: user, system, context switches, major faults, minor faults IO depths: <=1, 2, 4, 8, 16, 32, >=64