To specify power-of-2 binary values defined in IEC 80000-13:
- * *k* -- means kibi (Ki) or 1024
+ * *K* -- means kibi (Ki) or 1024
* *M* -- means mebi (Mi) or 1024**2
* *G* -- means gibi (Gi) or 1024**3
* *T* -- means tebi (Ti) or 1024**4
**float_list**
A list of floating point numbers, separated by a ':' character.
+With the above in mind, here follows the complete list of fio job parameters.
+
Units
~~~~~
Bit based.
-With the above in mind, here follows the complete list of fio job parameters.
-
-
Job description
~~~~~~~~~~~~~~~
typically won't work with direct I/O, as that normally requires sector
alignment.
-.. option:: bs_is_seq_rand
+.. option:: bs_is_seq_rand=bool
If this option is set, fio will use the normal read,write blocksize settings
as sequential,random blocksize settings instead. Any random read or write
**cudamalloc**
Use GPU memory as the buffers for GPUDirect RDMA benchmark.
+ The ioengine must be rdma.
The area allocated is a function of the maximum allowed bs size for the job,
multiplied by the I/O depth given. Note that for **shmhuge** and
[libhdfs]
- the listening port of the HFDS cluster namenode.
+ The listening port of the HFDS cluster namenode.
.. option:: interface=str : [netsplice] [net]
**0**
Default. Preallocate donor's file on init.
**1**
- Allocate space immediately inside defragment event, and free right
+ Allocate space immediately inside defragment event, and free right
after event.
.. option:: clustername=str : [rbd]
.. option:: chunk_size : [libhdfs]
- the size of the chunk to use for each file.
+ The size of the chunk to use for each file.
I/O depth
16 requests, it will let the depth drain down to 4 before starting to fill
it again.
+.. option:: serialize_overlap=bool
+
+ Serialize in-flight I/Os that might otherwise cause or suffer from data races.
+ When two or more I/Os are submitted simultaneously, there is no guarantee that
+ the I/Os will be processed or completed in the submitted order. Further, if
+ two or more of those I/Os are writes, any overlapping region between them can
+ become indeterminate/undefined on certain storage. These issues can cause
+ verification to fail erratically when at least one of the racing I/Os is
+ changing data and the overlapping region has a non-zero size. Setting
+ ``serialize_overlap`` tells fio to avoid provoking this behavior by explicitly
+ serializing in-flight I/Os that have a non-zero overlap. Note that setting
+ this option can reduce both performance and the `:option:iodepth` achieved.
+ Additionally this option does not work when :option:`io_submit_mode` is set to
+ offload. Default: false.
+
.. option:: io_submit_mode=str
This option controls how fio submits the I/O to the I/O engine. The default
replay, the file needs to be turned into a blkparse binary data file first
(``blkparse <device> -o /dev/null -d file_for_fio.bin``).
-.. option:: replay_no_stall=int
+.. option:: replay_no_stall=bool
When replaying I/O with :option:`read_iolog` the default behavior is to
attempt to respect the timestamps within the log and replay them with the
.. option:: verifysort_nr=int
- Pre-load and sort verify blocks for a read workload.
+ Pre-load and sort verify blocks for a read workload.
.. option:: verify_offset=int
.. option:: trim_backlog=int
- Verify that trim/discarded blocks are returned as zeros.
+ Trim after this number of blocks are written.
.. option:: trim_backlog_batch=int
Enable experimental verification.
-
Steady state
~~~~~~~~~~~~
all jobs in a file will be part of the same reporting group, unless
separated by a :option:`stonewall`.
-.. option:: stats
+.. option:: stats=bool
By default, fio collects and shows final output results for all jobs
that run. If this option is set to 0, then fio will ignore it in
you instead want to log the maximum value, set this option to 1. Defaults to
0, meaning that averaged values are logged.
-.. option:: log_offset=int
+.. option:: log_offset=bool
If this is set, the iolog options will include the byte offset for the I/O
entry as well as the other data values. Defaults to 0 meaning that
| 99.99th=[78119]
bw ( KiB/s): min= 532, max= 686, per=0.10%, avg=622.87, stdev=24.82, samples= 100
iops : min= 76, max= 98, avg=88.98, stdev= 3.54, samples= 100
- lat (usec) : 250=0.04%, 500=64.11%, 750=4.81%, 1000=2.79%
- lat (msec) : 2=4.16%, 4=1.84%, 10=4.90%, 20=11.33%, 50=5.37%
- lat (msec) : 100=0.65%
+ lat (usec) : 250=0.04%, 500=64.11%, 750=4.81%, 1000=2.79%
+ lat (msec) : 2=4.16%, 4=1.84%, 10=4.90%, 20=11.33%, 50=5.37%
+ lat (msec) : 100=0.65%
cpu : usr=0.27%, sys=0.18%, ctx=12072, majf=0, minf=21
IO depths : 1=85.0%, 2=13.1%, 4=1.8%, 8=0.1%, 16=0.0%, 32=0.0%, >=64=0.0%
submit : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
complete is basically just CPU time (I/O has already been done, see slat
explanation).
+**lat**
+ Total latency. Same names as slat and clat, this denotes the time from
+ when fio created the I/O unit to completion of the I/O operation.
+
**bw**
Bandwidth statistics based on samples. Same names as the xlat stats,
but also includes the number of samples taken (**samples**) and an
**iops**
IOPS statistics based on samples. Same names as bw.
+**lat (nsec/usec/msec)**
+ The distribution of I/O completion latencies. This is the time from when
+ I/O leaves fio and when it gets completed. Unlike the separate
+ read/write/trim sections above, the data here and in the remaining
+ sections apply to all I/Os for the reporting group. 250=0.04% means that
+ 0.04% of the I/Os completed in under 250us. 500=64.11% means that 64.11%
+ of the I/Os required 250 to 499us for completion.
+
**cpu**
CPU usage. User and system time, along with the number of context
switches this thread went through, usage of system and user time, and
The number of read/write/trim requests issued, and how many of them were
short or dropped.
-**IO latencies**
- The distribution of I/O completion latencies. This is the time from when
- I/O leaves fio and when it gets completed. The numbers follow the same
- pattern as the I/O depths, meaning that 2=1.6% means that 1.6% of the
- I/O completed within 2 msecs, 20=12.8% means that 12.8% of the I/O took
- more than 10 msecs, but less than (or equal to) 20 msecs.
+**IO latency**
+ These values are for `--latency-target` and related options. When
+ these options are engaged, this section describes the I/O depth required
+ to meet the specified latency target.
..
Example output was based on the following:
projects / fio.git / blobdiff