X-Git-Url: https://git.kernel.dk/?p=fio.git;a=blobdiff_plain;f=HOWTO;h=5e9b390bcf3902ce8f3d4400e102f49ace9f2329;hp=999f7778f37d9d9628f76189609411f7053e77b2;hb=21b8aee865f0d3960687ce6ba7385e5977f45061;hpb=2b7a01d01ea19f6e4090c7a8280bc6bf983e781f diff --git a/HOWTO b/HOWTO index 999f7778..5e9b390b 100644 --- a/HOWTO +++ b/HOWTO @@ -8,7 +8,7 @@ Table of contents 5. Detailed list of parameters 6. Normal output 7. Terse output - +8. Trace file format 1.0 Overview and history ------------------------ @@ -112,7 +112,7 @@ section residing above it. If the first character in a line is a ';' or a '#', the entire line is discarded as a comment. So let's look at a really simple job file that defines two processes, each -randomly reading from a 128MiB file. +randomly reading from a 128MB file. ; -- start job file -- [global] @@ -150,14 +150,17 @@ numjobs=4 Here we have no global section, as we only have one job defined anyway. We want to use async io here, with a depth of 4 for each file. We also -increased the buffer size used to 32KiB and define numjobs to 4 to +increased the buffer size used to 32KB and define numjobs to 4 to fork 4 identical jobs. The result is 4 processes each randomly writing -to their own 64MiB file. Instead of using the above job file, you could +to their own 64MB file. Instead of using the above job file, you could have given the parameters on the command line. For this case, you would 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 ------------------------------- @@ -197,21 +220,26 @@ 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. -time Integer with possible time postfix. In seconds unless otherwise +time Integer with possible time suffix. In seconds unless otherwise specified, use eg 10m for 10 minutes. Accepts s/m/h for seconds, minutes, and hours. -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 - 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. +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, 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, 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 postfix. Allows value range to be given, such +irange Integer range with suffix. 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 @@ -230,7 +258,7 @@ description=str Text description of the job. Doesn't do anything except dump this text description when this job is run. It's not parsed. -directory=str Prefix filenames with this directory. Used to places files +directory=str Prefix filenames with this directory. Used to place files in a different location than "./". filename=str Fio normally makes up a filename based on the job name, @@ -243,14 +271,19 @@ 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 - direction set. + filename=/dev/sda:/dev/sdb. On Windows, disk devices are accessed + as \\.\PhysicalDrive0 for the first device, \\.\PhysicalDrive1 + for the second etc. 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 directory and down the file system tree. -lockfile=str Fio defaults to not doing any locking files before it does +lockfile=str Fio defaults to not locking any files before it does IO to them. If a file or file descriptor is shared, fio can serialize IO to that file to make the end result consistent. This is usual for emulating real workloads that @@ -282,17 +315,59 @@ rw=str Type of io pattern. Accepted values are: For the mixed io types, the default is to split them 50/50. For certain types of io the result may still be skewed a bit, since the speed may be different. It is possible to specify - a number of IO's to do before getting a new offset - this - is only useful for random IO, where fio would normally - generate a new random offset for every IO. If you append - eg 8 to randread, you would get a new random offset for + 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. + +rw_sequencer=str If an offset modifier is given by appending a number to + the rw= line, then this option controls how that + number modifies the IO offset being generated. Accepted + values are: + + sequential Generate sequential offset + identical Generate the same offset + + 'sequential' is only useful for random IO, where fio would + normally generate a new random offset for every IO. If you + append eg 8 to randread, you would get a new random offset for every 8 IO's. The result would be a seek for only every 8 IO's, instead of for every IO. Use rw=randread:8 to specify - that. + that. As sequential IO is already sequential, setting + 'sequential' for that would not result in any differences. + 'identical' behaves in a similar fashion, except it sends + the same offset 8 number of times before generating a new + offset. + +kb_base=int The base unit for a kilobyte. The defacto base is 2^10, 1024. + Storage manufacturers like to use 10^3 or 1000 as a base + ten unit instead, for obvious reasons. Allow values are + 1024 or 1000, with 1024 being the default. randrepeat=bool For random IO workloads, seed the generator in a predictable way so that results are repeatable across repetitions. +use_os_rand=bool Fio can either use the random generator supplied by the OS + to generator random offsets, or it can use it's own internal + generator (based on Tausworthe). Default is to use the + internal generator, which is often of better quality and + faster. + +fallocate=str Whether pre-allocation is performed when laying down files. + Accepted values are: + + none Do not pre-allocate space + posix Pre-allocate via posix_fallocate() + keep Pre-allocate via fallocate() with + FALLOC_FL_KEEP_SIZE set + 0 Backward-compatible alias for 'none' + 1 Backward-compatible alias for 'posix' + + May not be available on all supported platforms. 'keep' is only + available on Linux.If using ZFS on Solaris this must be set to + 'none' because ZFS doesn't support it. Default: 'posix'. + 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 @@ -303,18 +378,29 @@ fadvise_hint=bool By default, fio will use fadvise() to advise the kernel 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, + Unless specific nrfiles and filesize options are given, fio will divide this size between the available files - specified by the job. + specified by the job. If not set, fio will use the full + size of the given files or devices. If the the files + do not exist, size must be given. It is also possible to + give size as a percentage between 1 and 100. If size=20% + is given, fio will use 20% of the full size of the given + files or devices. 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. -fill_device=bool Sets size to something really large and waits for ENOSPC (no +fill_device=bool +fill_fs=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. + sense with sequential write. For a read workload, the mount + point will be filled first then IO started on the result. This + option doesn't make sense if operating on a raw device node, + since the size of that is already known by the file system. + Additionally, writing beyond end-of-device will not return + ENOSPC there. blocksize=int bs=int The block size used for the io units. Defaults to 4k. Values @@ -367,6 +453,15 @@ 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 @@ -422,6 +517,8 @@ ioengine=str Defines how the job issues io to the file. The following solarisaio Solaris native asynchronous io. + windowsaio Windows native asynchronous io. + mmap File is memory mapped and data copied to/from using memcpy(3). @@ -471,6 +568,11 @@ 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. + external Prefix to specify loading an external IO engine object file. Append the engine filename, eg ioengine=external:/tmp/foo.o @@ -479,7 +581,14 @@ ioengine=str Defines how the job issues io to the file. The following iodepth=int This defines how many io units to keep in flight against the file. The default is 1 for each file defined in this job, can be overridden with a larger value for higher - concurrency. + concurrency. Note that increasing iodepth beyond 1 will not + affect synchronous ioengines (except for small degress when + verify_async is in use). Even async engines may impose OS + restrictions causing the desired depth not to be achieved. + This may happen on Linux when using libaio and not setting + direct=1, since buffered IO is not async on that OS. Keep an + eye on the IO depth distribution in the fio output to verify + that the achieved depth is as expected. Default: 1. iodepth_batch_submit=int iodepth_batch=int This defines how many pieces of IO to submit at once. @@ -504,7 +613,7 @@ iodepth_low=int The low water mark indicating when to start filling the depth drain down to 4 before starting to fill it again. direct=bool If value is true, use non-buffered io. This is usually - O_DIRECT. + O_DIRECT. Note that ZFS on Solaris doesn't support direct io. buffered=bool If value is true, use buffered io. This is the opposite of the 'direct' option. Defaults to true. @@ -520,6 +629,25 @@ 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. +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 created before the write phase begins. If the file exists @@ -537,7 +665,9 @@ rwmixread=int How large a percentage of the mix should be reads. rwmixwrite=int How large a percentage of the mix should be writes. If both rwmixread and rwmixwrite is given and the values do not add up to 100%, the latter of the two will be used to override - the first. + the first. This may interfere with a given rate setting, + if fio is asked to limit reads or writes to a certain rate. + If that is the case, then the distribution may be skewed. norandommap Normally fio will cover every block of the file when doing random IO. If this option is given, fio will just get a @@ -579,19 +709,29 @@ thinktime_blocks defaults to 1 which will make fio wait 'thinktime' usecs after every block. -rate=int Cap the bandwidth used by this job to this number of KiB/sec. +rate=int Cap the bandwidth used by this job. The number is in bytes/sec, + the normal suffix rules apply. You can use rate=500k to limit + reads and writes to 500k each, or you can specify read and + writes separately. Using rate=1m,500k would limit reads to + 1MB/sec and writes to 500KB/sec. Capping only reads or + writes can be done with rate=,500k or rate=500k,. The former + will only limit writes (to 500KB/sec), the latter will only + limit reads. ratemin=int Tell fio to do whatever it can to maintain at least this bandwidth. Failing to meet this requirement, will cause - the job to exit. + the job to exit. The same format as rate is used for + read vs write separation. rate_iops=int Cap the bandwidth to this number of IOPS. Basically the same as rate, just specified independently of bandwidth. If the job is given a block size range instead of a fixed value, - the smallest block size is used as the metric. + the smallest block size is used as the metric. The same format + as rate is used for read vs write seperation. rate_iops_min=int If fio doesn't meet this rate of IO, it will cause - the job to exit. + the job to exit. The same format as rate is used for read vs + write seperation. ratecycle=int Average bandwidth for 'rate' and 'ratemin' over this number of milliseconds. @@ -666,7 +806,7 @@ mem=str Fio can use various types of memory as the io unit buffer. that for shmhuge and mmaphuge to work, the system must have free huge pages allocated. This can normally be checked and set by reading/writing /proc/sys/vm/nr_hugepages on a - Linux system. Fio assumes a huge page is 4MiB in size. So + Linux system. Fio assumes a huge page is 4MB in size. So to calculate the number of huge pages you need for a given job file, add up the io depth of all jobs (normally one unless iodepth= is used) and multiply by the maximum bs set. Then @@ -679,9 +819,18 @@ 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. +iomem_align=int This indiciates the memory alignment of the IO memory buffers. + Note that the given alignment is applied to the first IO unit + buffer, if using iodepth the alignment of the following buffers + are given by the bs used. In other words, if using a bs that is + a multiple of the page sized in the system, all buffers will + be aligned to this value. If using a bs that is not page + aligned, the alignment of subsequent IO memory buffers is the + sum of the iomem_align and bs used. + 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. + to the system setting, see /proc/meminfo. Defaults to 4MB. Should probably always be a multiple of megabytes, so using hugepage-size=Xm is the preferred way to set this to avoid setting a non-pow-2 bad value. @@ -704,6 +853,14 @@ create_fsync=bool fsync the data file after creation. This is the create_on_open=bool Don't pre-setup the files for IO, just create open() when it's time to do IO to that file. +pre_read=bool If this is given, files will be pre-read into memory before + starting the given IO operation. This will also clear + the 'invalidate' flag, since it is pointless to pre-read + and then drop the cache. This will only work for IO engines + that are seekable, since they allow you to read the same data + multiple times. Thus it will not work on eg network or splice + IO. + unlink=bool Unlink the job files when done. Not the default, as repeated runs of that job would then waste time recreating the file set again and again. @@ -729,7 +886,9 @@ 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. @@ -744,9 +903,11 @@ 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. + number is verified. See also verify_pattern. null Only pretend to verify. Useful for testing internals with ioengine=null, not for much @@ -754,7 +915,11 @@ 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 @@ -773,18 +938,59 @@ 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". Use + with verify=meta. verify_fatal=bool Normally fio will keep checking the entire contents before quitting on a block verification failure. If this option is set, fio will exit the job on the first observed failure. + +verify_dump=bool If set, dump the contents of both the original data + block and the data block we read off disk to files. This + allows later analysis to inspect just what kind of data + corruption occurred. On by default. + +verify_async=int Fio will normally verify IO inline from the submitting + thread. This option takes an integer describing how many + async offload threads to create for IO verification instead, + causing fio to offload the duty of verifying IO contents + to one or more separate threads. If using this offload + option, even sync IO engines can benefit from using an + iodepth setting higher than 1, as it allows them to have + IO in flight while verifies are running. + +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 write only N blocks before verifying these blocks. + + 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). If verify_backlog_batch is + less than verify_backlog then not all blocks will be verified, + 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 starting this one. Can be used to insert serialization @@ -819,7 +1025,8 @@ zoneskip=int Skip the specified number of bytes when zonesize data has io on zones of a file. write_iolog=str Write the issued io patterns to the specified file. See - read_iolog. + read_iolog. Specify a separate file for each job, otherwise + the iologs will be interspersed and the file may be corrupt. read_iolog=str Open an iolog with the specified file name and replay the io patterns it contains. This can be used to store a @@ -828,7 +1035,32 @@ 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). + +replay_no_stall=int When replaying I/O with read_iolog the default behavior + is to attempt to respect the time stamps within the log and + replay them with the appropriate delay between IOPS. By + setting this variable fio will not respect the timestamps and + attempt to replay them as fast as possible while still + respecting ordering. The result is the same I/O pattern to a + given device, but different timings. + +replay_redirect=str While replaying I/O patterns using read_iolog the + default behavior is to replay the IOPS onto the major/minor + device that each IOP was recorded from. This is sometimes + undesireable because on a different machine those major/minor + numbers can map to a different device. Changing hardware on + the same system can also result in a different major/minor + mapping. Replay_redirect causes all IOPS to be replayed onto + the single specified device regardless of the device it was + recorded from. i.e. replay_redirect=/dev/sdc would cause all + IO in the blktrace to be replayed onto /dev/sdc. This means + multiple devices will be replayed onto a single, if the trace + contains multiple devices. If you want multiple devices to be + replayed concurrently to multiple redirected devices you must + blkparse your trace into separate traces and replay them with + independent fio invocations. Unfortuantely this also breaks + the strict time ordering between multiple device accesses. 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 @@ -838,15 +1070,16 @@ write_bw_log=str If given, write a bandwidth log of the jobs in this job filename. For this option, the postfix is _bw.log. write_lat_log=str Same as write_bw_log, except that this option stores io - completion latencies instead. If no filename is given - with this option, the default filename of "jobname_type.log" - is used. Even if the filename is given, fio will still - append the type of log. So if one specifies + submission, completion, and total latencies instead. If no + filename is given with this option, the default filename of + "jobname_type.log" is used. Even if the filename is given, + fio will still append the type of log. So if one specifies write_lat_log=foo - The actual log names will be foo_clat.log and foo_slat.log. - This helps fio_generate_plot fine the logs automatically. + The actual log names will be foo_slat.log, foo_slat.log, + and foo_lat.log. This helps fio_generate_plot fine the logs + automatically. lockmem=int Pin down the specified amount of memory with mlock(2). Can potentially be used instead of removing memory or booting @@ -865,23 +1098,26 @@ cpuload=int If the job is a CPU cycle eater, attempt to use the specified percentage of CPU cycles. cpuchunks=int If the job is a CPU cycle eater, split the load into - cycles of the given time. In milliseconds. + cycles of the given time. In microseconds. disk_util=bool Generate disk utilization statistics, if the platform supports it. Defaults to on. -disable_clat=bool Disable measurements of completion latency numbers. Useful +disable_lat=bool Disable measurements of total latency numbers. Useful only for cutting back the number of calls to gettimeofday, as that does impact performance at really high IOPS rates. Note that to really get rid of a large amount of these calls, this option must be used with disable_slat and disable_bw as well. +disable_clat=bool Disable measurements of completion latency numbers. See + disable_lat. + disable_slat=bool Disable measurements of submission latency numbers. See - disable_clat. + disable_slat. disable_bw=bool Disable measurements of throughput/bandwidth numbers. See - disable_clat. + disable_lat. gtod_reduce=bool Enable all of the gettimeofday() reducing options (disable_clat, disable_slat, disable_bw) plus reduce @@ -902,6 +1138,36 @@ gtod_cpu=int Sometimes it's cheaper to dedicate a single thread of 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 + is exceeded or the I/O size specified is completed. If this + option is used, there are two more stats that are appended, + the total error count and the first error. The error field + 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 --------------------------- @@ -919,6 +1185,7 @@ Idle Run P Thread setup, but not started. C Thread created. I Thread initialized, waiting. + p Thread running pre-reading file(s). R Running, doing sequential reads. r Running, doing random reads. W Running, doing sequential writes. @@ -926,7 +1193,7 @@ 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. @@ -941,10 +1208,10 @@ each thread, group of threads, and disks in that order. For each data direction, the output looks like: Client1 (g=0): err= 0: - write: io= 32MiB, bw= 666KiB/s, runt= 50320msec + write: io= 32MB, bw= 666KB/s, iops=89 , runt= 50320msec slat (msec): min= 0, max= 136, avg= 0.03, stdev= 1.92 clat (msec): min= 0, max= 631, avg=48.50, stdev=86.82 - bw (KiB/s) : min= 0, max= 1196, per=51.00%, avg=664.02, stdev=681.68 + bw (KB/s) : min= 0, max= 1196, per=51.00%, avg=664.02, stdev=681.68 cpu : usr=1.49%, sys=0.25%, ctx=7969, majf=0, minf=17 IO depths : 1=0.1%, 2=0.3%, 4=0.5%, 8=99.0%, 16=0.0%, 32=0.0%, >32=0.0% submit : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0% @@ -959,6 +1226,7 @@ they denote: io= Number of megabytes io performed bw= Average bandwidth rate +iops= Average IOs performed per second runt= The runtime of that thread slat= Submission latency (avg being the average, stdev being the standard deviation). This is the time it took to submit @@ -1004,8 +1272,8 @@ After each client has been listed, the group statistics are printed. They will look like this: Run status group 0 (all jobs): - READ: io=64MiB, aggrb=22178, minb=11355, maxb=11814, mint=2840msec, maxt=2955msec - WRITE: io=64MiB, aggrb=1302, minb=666, maxb=669, mint=50093msec, maxt=50320msec + READ: io=64MB, aggrb=22178, minb=11355, maxb=11814, mint=2840msec, maxt=2955msec + WRITE: io=64MB, aggrb=1302, minb=666, maxb=669, mint=50093msec, maxt=50320msec For each data direction, it prints: @@ -1039,26 +1307,96 @@ For scripted usage where you typically want to generate tables or graphs of the results, fio can output the results in a semicolon separated format. The format is one long line of values, such as: -client1;0;0;1906777;1090804;1790;0;0;0.000000;0.000000;0;0;0.000000;0.000000;929380;1152890;25.510151%;1078276.333333;128948.113404;0;0;0;0;0;0.000000;0.000000;0;0;0.000000;0.000000;0;0;0.000000%;0.000000;0.000000;100.000000%;0.000000%;324;100.0%;0.0%;0.0%;0.0%;0.0%;0.0%;0.0%;100.0%;0.0%;0.0%;0.0%;0.0%;0.0% -;0.0%;0.0%;0.0%;0.0%;0.0% +2;card0;0;0;7139336;121836;60004;1;10109;27.932460;116.933948;220;126861;3495.446807;1085.368601;226;126864;3523.635629;1089.012448;24063;99944;50.275485%;59818.274627;5540.657370;7155060;122104;60004;1;8338;29.086342;117.839068;388;128077;5032.488518;1234.785715;391;128085;5061.839412;1236.909129;23436;100928;50.287926%;59964.832030;5644.844189;14.595833%;19.394167%;123706;0;7313;0.1%;0.1%;0.1%;0.1%;0.1%;0.1%;100.0%;0.00%;0.00%;0.00%;0.00%;0.00%;0.00%;0.01%;0.02%;0.05%;0.16%;6.04%;40.40%;52.68%;0.64%;0.01%;0.00%;0.01%;0.00%;0.00%;0.00%;0.00%;0.00% +A description of this job goes here. -To enable terse output, use the --minimal command line option. +The job description (if provided) follows on a second line. + +To enable terse output, use the --minimal command line option. The first +value is the version of the terse output format. If the output has to +be changed for some reason, this number will be incremented by 1 to +signify that change. Split up, the format is as follows: - jobname, groupid, error + version, jobname, groupid, error READ status: - KiB IO, bandwidth (KiB/sec), runtime (msec) + KB IO, bandwidth (KB/sec), runtime (msec) Submission latency: min, max, mean, deviation Completion latency: min, max, mean, deviation + Total latency: min, max, mean, deviation Bw: min, max, aggregate percentage of total, mean, deviation WRITE status: - KiB IO, bandwidth (KiB/sec), runtime (msec) + KB IO, bandwidth (KB/sec), runtime (msec) Submission latency: min, max, mean, deviation Completion latency: min, max, mean, deviation + Total latency: min, max, mean, deviation 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 - IO latencies: <=2, 4, 10, 20, 50, 100, 250, 500, 750, 1000, >=2000 - Text description + IO latencies microseconds: <=2, 4, 10, 20, 50, 100, 250, 500, 750, 1000 + IO latencies milliseconds: <=2, 4, 10, 20, 50, 100, 250, 500, 750, 1000, 2000, >=2000 + Additional Info (dependant on continue_on_error, default off): total # errors, first error code + + Additional Info (dependant on description being set): Text description + + +8.0 Trace file format +--------------------- +There are two trace file format that you can encounter. The older (v1) format +is unsupported since version 1.20-rc3 (March 2008). It will still be described +below in case that you get an old trace and want to understand it. + +In any case the trace is a simple text file with a single action per line. + + +8.1 Trace file format v1 +------------------------ +Each line represents a single io action in the following format: + +rw, offset, length + +where rw=0/1 for read/write, and the offset and length entries being in bytes. + +This format is not supported in Fio versions => 1.20-rc3. + + +8.2 Trace file format v2 +------------------------ +The second version of the trace file format was added in Fio version 1.17. +It allows to access more then one file per trace and has a bigger set of +possible file actions. + +The first line of the trace file has to be: + +fio version 2 iolog + +Following this can be lines in two different formats, which are described below. + +The file management format: + +filename action + +The filename is given as an absolute path. The action can be one of these: + +add Add the given filename to the trace +open Open the file with the given filename. The filename has to have + been added with the add action before. +close Close the file with the given filename. The file has to have been + opened before. + + +The file io action format: + +filename action offset length + +The filename is given as an absolute path, and has to have been added and opened +before it can be used with this format. The offset and length are given in +bytes. The action can be one of these: +wait Wait for 'offset' microseconds. Everything below 100 is discarded. +read Read 'length' bytes beginning from 'offset' +write Write 'length' bytes beginning from 'offset' +sync fsync() the file +datasync fdatasync() the file +trim trim the given file from the given 'offset' for 'length' bytes