X-Git-Url: https://git.kernel.dk/?p=fio.git;a=blobdiff_plain;f=HOWTO;h=6c7f05b9efde3334e5260b4c86371216d43de3b3;hp=dc70ab6693688e4078713abd0292bb8036915035;hb=eef16f316456526b0a52fdfce2b70c12d7ad1b5b;hpb=b09da8fa5be85634a3e8331d6e5ce07cd427a5a2 diff --git a/HOWTO b/HOWTO index dc70ab66..6c7f05b9 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 ------------------------------- @@ -243,8 +266,11 @@ filename=str Fio normally makes up a filename based on the job name, can specify a number of files by separating the names with a ':' colon. So if you wanted a job to open /dev/sda and /dev/sdb as the two working files, you would use - filename=/dev/sda:/dev/sdb. '-' is a reserved name, meaning - stdin or stdout. Which of the two depends on the read/write + filename=/dev/sda:/dev/sdb. If the wanted filename does need to + include a colon, then escape that with a '\' character. For + instance, if the filename is "/dev/dsk/foo@3,0:c", then you would + use filename="/dev/dsk/foo@3,0\:c". '-' is a reserved name, + meaning stdin or stdout. Which of the two depends on the read/write direction set. opendir=str Tell fio to recursively add any file it can find in this @@ -298,6 +324,11 @@ 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 @@ -535,8 +566,24 @@ 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 @@ -791,6 +838,8 @@ 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. @@ -801,7 +850,11 @@ 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 @@ -820,13 +873,14 @@ 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 @@ -961,6 +1015,7 @@ 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 @@ -970,6 +1025,21 @@ 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. + +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 ---------------------------