X-Git-Url: https://git.kernel.dk/?p=fio.git;a=blobdiff_plain;f=HOWTO;h=26a9b93b63037adb98a8d1de15c150cd31245d27;hp=f569f5622de5db7d28d0fb3b7319b6aee9545ef1;hb=26eca2db3ef6e92ff1022099cb89fc8ce88ee15d;hpb=1025d13dc9b230ac798eda37c7f3bb4471951a00 diff --git a/HOWTO b/HOWTO index f569f562..26a9b93b 100644 --- a/HOWTO +++ b/HOWTO @@ -111,7 +111,7 @@ several global sections if so desired. A job is only affected by a global section residing above it. If the first character in a line is a ';' or a '#', the entire line is discarded as a comment. -So lets look at a really simple job file that define to threads, each +So let's look at a really simple job file that defines two processes, each randomly reading from a 128MiB file. ; -- start job file -- @@ -133,7 +133,7 @@ line, this job would look as follows: $ fio --name=global --rw=randread --size=128m --name=job1 --name=job2 -Lets look at an example that have a number of processes writing randomly +Let's look at an example that has a number of processes writing randomly to files. ; -- start job file -- @@ -158,6 +158,33 @@ specify: $ fio --name=random-writers --ioengine=libaio --iodepth=4 --rw=randwrite --bs=32k --direct=0 --size=64m --numjobs=4 +fio also supports environment variable expansion in job files. Any +substring of the form "${VARNAME}" as part of an option value (in other +words, on the right of the `='), will be expanded to the value of the +environment variable called VARNAME. If no such environment variable +is defined, or VARNAME is the empty string, the empty string will be +substituted. + +As an example, let's look at a sample fio invocation and job file: + +$ SIZE=64m NUMJOBS=4 fio jobfile.fio + +; -- start job file -- +[random-writers] +rw=randwrite +size=${SIZE} +numjobs=${NUMJOBS} +; -- end job file -- + +This will expand to the following equivalent job file at runtime: + +; -- start job file -- +[random-writers] +rw=randwrite +size=64m +numjobs=4 +; -- end job file -- + fio ships with a few example job files, you can also look there for inspiration. @@ -170,22 +197,25 @@ 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). -siint SI integer. A whole number value, which may contain a postfix +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. +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. See irange. + 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 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. @@ -207,14 +237,15 @@ filename=str Fio normally makes up a filename based on the job name, thread number, and file number. If you want to share files between threads in a job or several jobs, specify a filename for each of them to override the default. If - the ioengine used is 'net', the filename is the host and - port to connect to in the format of =host/port. If the - ioengine is file based, you 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. + the ioengine used is 'net', the filename is the host, port, + and protocol to use in the format of =host/port/protocol. + See ioengine=net for more. If the ioengine is file based, you + 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. opendir=str Tell fio to recursively add any file it can find in this directory and down the file system tree. @@ -269,14 +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. @@ -285,10 +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 @@ -296,6 +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 @@ -328,6 +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 @@ -356,6 +404,10 @@ file_service_type=str Defines how fio decides which file from a job to roundrobin Round robin over open files. This is the default. + sequential Finish one file before moving on to + the next. Multiple files can still be + open depending on 'openfiles'. + The string can have a number appended, indicating how often to switch to a new file. So if option random:4 is given, fio will switch to a new random file after 4 ios @@ -371,7 +423,9 @@ ioengine=str Defines how the job issues io to the file. The following vsync Basic readv(2) or writev(2) IO. - libaio Linux native asynchronous io. + libaio Linux native asynchronous io. Note that Linux + may only support queued behaviour with + non-buffered IO (set direct=1 or buffered=0). posixaio glibc posix asynchronous io. @@ -399,9 +453,12 @@ ioengine=str Defines how the job issues io to the file. The following net Transfer over the network to given host:port. 'filename' must be set appropriately to - filename=host/port regardless of send + filename=host/port/protocol regardless of send or receive, if the latter only the port - argument is used. + argument is used. 'host' may be an IP address + or hostname, port is the port number to be used, + and protocol may be 'udp' or 'tcp'. If no + protocol is given, TCP is used. netsplice Like net, but uses splice/vmsplice to map data and send/receive. @@ -461,7 +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. @@ -496,9 +553,9 @@ norandommap Normally fio will cover every block of the file when doing new random offset without looking at past io history. This means that some blocks may not be read or written, and that some blocks may be read/written more than once. This option - is mutually exclusive with verify= for that reason, since - fio doesn't track potential block rewrites which may alter - the calculated checksum for that block. + is mutually exclusive with verify= if and only if multiple + blocksizes (via bsrange=) are used, since fio only tracks + complete rewrites of blocks. softrandommap See norandommap. If fio runs with the random block map enabled and it fails to allocate the map, if this option is set it @@ -553,18 +610,23 @@ cpumask=int Set the CPU affinity of this job. The parameter given is a the allowed CPUs to be 1 and 5, you would pass the decimal value of (1 << 1 | 1 << 5), or 34. See man sched_setaffinity(2). This may not work on all supported - operating systems or kernel versions. + operating systems or kernel versions. This option doesn't + work well for a higher CPU count than what you can store in + an integer mask, so it can only control cpus 1-32. For + boxes with larger CPU counts, use cpus_allowed. cpus_allowed=str Controls the same options as cpumask, but it allows a text setting of the permitted CPUs instead. So to use CPUs 1 and - 5, you would specify cpus_allowed=1,5. + 5, you would specify cpus_allowed=1,5. This options also + allows a range of CPUs. Say you wanted a binding to CPUs + 1, 5, and 8-15, you would set cpus_allowed=1,5,8-15. -startdelay=int Start this job the specified number of seconds after fio +startdelay=time Start this job the specified number of seconds after fio has started. Only useful if the job file contains several jobs, and you want to delay starting some jobs to a certain time. -runtime=int Tell fio to terminate processing after the specified number +runtime=time Tell fio to terminate processing after the specified number of seconds. It can be quite hard to determine for how long a specified job will run, so this parameter is handy to cap the total runtime to a given time. @@ -574,6 +636,14 @@ time_based If set, fio will run for the duration of the runtime written. It will simply loop over the same workload as many times as the runtime allows. +ramp_time=time If set, fio will run the specified workload for this amount + of time before logging any performance numbers. Useful for + letting performance settle before logging results, thus + minimizing the runtime required for stable results. Note + that the ramp_time is considered lead in time for a job, + thus it will increase the total runtime if a special timeout + or runtime is specified. + invalidate=bool Invalidate the buffer/page cache parts for this file prior to starting io. Defaults to true. @@ -618,7 +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 @@ -640,6 +710,9 @@ create_serialize=bool If true, serialize the file creating for the jobs. create_fsync=bool fsync the data file after creation. This is the default. +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. + 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. @@ -664,6 +737,9 @@ verify=str If writing to a file, fio can verify the file contents crc32c Use a crc32c sum of the data area and store it in the header of each block. + crc32c-intel Use hardware assisted crc32c calcuation + provided on SSE4.2 enabled processors. + crc32 Use a crc32 sum of the data area and store it in the header of each block. @@ -697,11 +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. @@ -745,9 +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. @@ -763,16 +839,25 @@ read_iolog=str Open an iolog with the specified file name and replay the the file needs to be turned into a blkparse binary data file first (blktrace -d file_for_fio.bin). -write_bw_log If given, write a bandwidth log of the jobs in this job +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 jobs in their lifetime. The included fio_generate_plots script uses gnuplot to turn these text files into nice - graphs. + graphs. See write_log_log for behaviour of given + 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 -write_lat_log Same as write_bw_log, except that this option stores io - completion latencies instead. + write_lat_log=foo -lockmem=siint Pin down the specified amount of memory with mlock(2). Can + The actual log names will be foo_clat.log and foo_slat.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 with less memory to simulate a smaller amount of memory. @@ -789,11 +874,43 @@ 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 + 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_slat=bool Disable measurements of submission latency numbers. See + disable_clat. + +disable_bw=bool Disable measurements of throughput/bandwidth numbers. See + disable_clat. + +gtod_reduce=bool Enable all of the gettimeofday() reducing options + (disable_clat, disable_slat, disable_bw) plus reduce + precision of the timeout somewhat to really shrink + the gettimeofday() call count. With this option enabled, + we only do about 0.4% of the gtod() calls we would have + done if all time keeping was enabled. + +gtod_cpu=int Sometimes it's cheaper to dedicate a single thread of + execution to just getting the current time. Fio (and + databases, for instance) are very intensive on gettimeofday() + calls. With this option, you can set one CPU aside for + doing nothing but logging current time to a shared memory + location. Then the other threads/processes that run IO + workloads need only copy that segment, instead of entering + the kernel with a gettimeofday() call. The CPU set aside + for doing these time calls will be excluded from other + uses. Fio will manually clear it from the CPU mask of other + jobs. + 6.0 Interpreting the output --------------------------- @@ -818,7 +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. @@ -934,6 +1051,8 @@ 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% +To enable terse output, use the --minimal command line option. + Split up, the format is as follows: jobname, groupid, error