X-Git-Url: https://git.kernel.dk/?p=fio.git;a=blobdiff_plain;f=HOWTO;h=cafe1893656cfdff733c9b4368a92396ce9bd46c;hp=aec00e84e548f1c9d65952e73803d8fcb5df53e9;hb=57fc29faae372cb474b5f2ef921638ab28bb9dc0;hpb=8e827d35068326950a6781d93aeef33b66d3438b diff --git a/HOWTO b/HOWTO index aec00e84..cafe1893 100644 --- a/HOWTO +++ b/HOWTO @@ -158,6 +158,9 @@ specify: $ fio --name=random-writers --ioengine=libaio --iodepth=4 --rw=randwrite --bs=32k --direct=0 --size=64m --numjobs=4 +4.1 Environment variables +------------------------- + fio also supports environment variable expansion in job files. Any substring of the form "${VARNAME}" as part of an option value (in other words, on the right of the `='), will be expanded to the value of the @@ -188,6 +191,26 @@ numjobs=4 fio ships with a few example job files, you can also look there for inspiration. +4.2 Reserved keywords +--------------------- + +Additionally, fio has a set of reserved keywords that will be replaced +internally with the appropriate value. Those keywords are: + +$pagesize The architecture page size of the running system +$mb_memory Megabytes of total memory in the system +$ncpus Number of online available CPUs + +These can be used on the command line or in the job file, and will be +automatically substituted with the current system values when the job +is run. Simple math is also supported on these keywords, so you can +perform actions like: + +size=8*$mb_memory + +and get that properly expanded to 8 times the size of memory in the +machine. + 5.0 Detailed list of parameters ------------------------------- @@ -203,12 +226,17 @@ time Integer with possible time suffix. In seconds unless otherwise int SI integer. A whole number value, which may contain a suffix describing the base of the number. Accepted suffixes are k/m/g/t/p, meaning kilo, mega, giga, tera, and peta. The suffix is not case - sensitive. So if you want to specify 4096, you could either write + sensitive, and you may also include trailing 'b' (eg 'kb' is the same + as 'k'). So if you want to specify 4096, you could either write out '4096' or just give 4k. The suffixes signify base 2 values, so - 1024 is 1k and 1024k is 1m and so on. If the option accepts an upper - and lower range, use a colon ':' or minus '-' to separate such values. - May also include a prefix to indicate numbers base. If 0x is used, - the number is assumed to be hexadecimal. See irange. + 1024 is 1k and 1024k is 1m and so on, unless the suffix is explicitly + set to a base 10 value using 'kib', 'mib', 'gib', etc. If that is the + case, then 1000 is used as the multiplier. This can be handy for + disks, since manufacturers generally use base 10 values when listing + the capacity of a drive. If the option accepts an upper and lower + range, use a colon ':' or minus '-' to separate such values. May also + include a prefix to indicate numbers base. If 0x is used, the number + is assumed to be hexadecimal. See irange. bool Boolean. Usually parsed as an integer, however only defined for true and false (1 and 0). irange Integer range with suffix. Allows value range to be given, such @@ -301,6 +329,11 @@ kb_base=int The base unit for a kilobyte. The defacto base is 2^10, 1024. randrepeat=bool For random IO workloads, seed the generator in a predictable way so that results are repeatable across repetitions. +fallocate=bool By default, fio will use fallocate() to advise the system + of the size of the file we are going to write. This can be + turned off with fallocate=0. May not be available on all + supported platforms. + fadvise_hint=bool By default, fio will use fadvise() to advise the kernel on what IO patterns it is likely to issue. Sometimes you want to test specific IO patterns without telling the @@ -538,8 +571,24 @@ fsync=int If writing to a file, issue a sync of the dirty data not sync the file. The exception is the sg io engine, which synchronizes the disk cache anyway. -fsyncdata=int Like fsync= but uses fdatasync() to only sync data and not +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 + 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 + have happened since the last sync_file_range() call. 'str' + can currently be one or more of: + + wait_before SYNC_FILE_RANGE_WAIT_BEFORE + write SYNC_FILE_RANGE_WRITE + wait_after SYNC_FILE_RANGE_WAIT_AFTER + + So if you do sync_file_range=wait_before,write:8, fio would + use SYNC_FILE_RANGE_WAIT_BEFORE | SYNC_FILE_RANGE_WRITE for + every 8 writes. Also see the sync_file_range(2) man page. + This option is Linux specific. overwrite=bool If true, writes to a file will always overwrite existing data. If the file doesn't already exist, it will be @@ -779,7 +828,9 @@ verify=str If writing to a file, fio can verify the file contents it in the header of each block. crc32c-intel Use hardware assisted crc32c calcuation - provided on SSE4.2 enabled processors. + provided on SSE4.2 enabled processors. Falls + back to regular software crc32c, if not + supported by the system. crc32 Use a crc32 sum of the data area and store it in the header of each block. @@ -794,6 +845,8 @@ verify=str If writing to a file, fio can verify the file contents sha256 Use sha256 as the checksum function. + sha1 Use optimized sha1 as the checksum function. + meta Write extra information about each io (timestamp, block number etc.). The block number is verified. @@ -804,7 +857,11 @@ verify=str If writing to a file, fio can verify the file contents This option can be used for repeated burn-in tests of a system to make sure that the written data is also - correctly read back. + correctly read back. If the data direction given is + a read or random read, fio will assume that it should + verify a previously written file. If the data direction + includes any form of write, the verify will be of the + newly written data. verifysort=bool If set, fio will sort written verify blocks when it deems it faster to read them back in a sorted manner. This is @@ -823,13 +880,14 @@ verify_interval=int Write the verification header at a finer granularity size of header_interval. blocksize should divide this evenly. -verify_pattern=int If set, fio will fill the io buffers with this +verify_pattern=str If set, fio will fill the io buffers with this pattern. Fio defaults to filling with totally random bytes, but sometimes it's interesting to fill with a known pattern for io verification purposes. Depending on the width of the pattern, fio will fill 1/2/3/4 bytes of the - buffer at the time. The verify_pattern cannot be larger than - a 32-bit quantity. + 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". verify_fatal=bool Normally fio will keep checking the entire contents before quitting on a block verification failure. If this @@ -848,6 +906,22 @@ verify_async=int Fio will normally verify IO inline from the submitting verify_async_cpus=str Tell fio to set the given CPU affinity on the async IO verification threads. See cpus_allowed for the format used. + +verify_backlog=int Fio will normally verify the written contents of a + job that utilizes verify once that job has completed. In + other words, everything is written then everything is read + back and verified. You may want to verify continually + instead for a variety of reasons. Fio stores the meta data + associated with an IO block in memory, so for large + verify workloads, quite a bit of memory would be used up + holding this meta data. If this option is enabled, fio + will verify the previously written blocks before continuing + to write new ones. + +verify_backlog_batch=int Control how many blocks fio will verify + if verify_backlog is set. If not set, will default to + the value of verify_backlog (meaning the entire queue + is read back and verified). stonewall Wait for preceeding jobs in the job file to exit, before starting this one. Can be used to insert serialization @@ -891,7 +965,7 @@ read_iolog=str Open an iolog with the specified file name and replay the to replay a workload captured by blktrace. See blktrace for how to capture such logging data. For blktrace replay, the file needs to be turned into a blkparse binary data - file first (blktrace -d file_for_fio.bin). + file first (blkparse -o /dev/null -d file_for_fio.bin). write_bw_log=str If given, write a bandwidth log of the jobs in this job file. Can be used to store data of the bandwidth of the @@ -964,6 +1038,7 @@ gtod_cpu=int Sometimes it's cheaper to dedicate a single thread of for doing these time calls will be excluded from other uses. Fio will manually clear it from the CPU mask of other jobs. + continue_on_error=bool Normally fio will exit the job on the first observed failure. If this option is set, fio will continue the job when there is a 'non-fatal error' (EIO or EILSEQ) until the runtime @@ -973,6 +1048,27 @@ continue_on_error=bool Normally fio will exit the job on the first observed given in the stats is the first error that was hit during the run. +cgroup=str Add job to this control group. If it doesn't exist, it will + be created. The system must have a mounted cgroup blkio + mount point for this to work. If your system doesn't have it + mounted, you can do so with: + + # mount -t cgroup -o blkio none /cgroup + +cgroup_weight=int Set the weight of the cgroup to this value. See + the documentation that comes with the kernel, allowed values + are in the range of 100..1000. + +cgroup_nodelete=bool Normally fio will delete the cgroups it has created after + the job completion. To override this behavior and to leave + cgroups around after the job completion, set cgroup_nodelete=1. + This can be useful if one wants to inspect various cgroup + files after job completion. Default: false + +uid=int Instead of running as the invoking user, set the user ID to + this value before the thread/process does any work. + +gid=int Set group ID, see uid. 6.0 Interpreting the output ---------------------------