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fio will do certain actions depending on the backing file type of the target that it runs against. (E.g. if the zbd code in fio detects that the backing file is FIO_TYPE_FILE, it will emulate zones inside the regular file.) Both SPDK ioengines reuse the filename option to not point to an actual path exposed by the OS, but to instead point to a device in the SPDK namespace. Because of this, the file type detection in fio will fail, and will always initialize filetype to FIO_TYPE_FILE. Therefore, the SPDK ioengines will need to initialize f->filetype themselves. The SPDK nvme ioengine already initializes f->filetype to FIO_TYPE_BLOCK unconditionally. Do the same in the SPDK bdev ioengine. (Just like in the SPDK nvme ioengine, we also need to call fio_file_set_size_known(), so that fio generic code does not try to initialize f->real_file_size.) Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com> Change-Id: I37df185524ed262cb875105f989685b740b430a3 Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/8328 Reviewed-by: Jim Harris <james.r.harris@intel.com> Reviewed-by: Paul Luse <paul.e.luse@intel.com> Reviewed-by: Changpeng Liu <changpeng.liu@intel.com> Community-CI: Mellanox Build Bot Tested-by: SPDK CI Jenkins <sys_sgci@intel.com> |
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| .. | ||
| .gitignore | ||
| bdev_zoned.json | ||
| bdev.json | ||
| example_config.fio | ||
| fio_plugin.c | ||
| full_bench.fio | ||
| Makefile | ||
| README.md | ||
| zbd_example.fio | ||
Introduction
This directory contains a plug-in module for fio to enable use with SPDK. Fio is free software published under version 2 of the GPL license.
Compiling fio
Clone the fio source repository from https://github.com/axboe/fio
git clone https://github.com/axboe/fio
cd fio
Compile the fio code and install:
make
make install
Compiling SPDK
Clone the SPDK source repository from https://github.com/spdk/spdk
git clone https://github.com/spdk/spdk
cd spdk
git submodule update --init
Then, run the SPDK configure script to enable fio (point it to the root of the fio repository):
cd spdk
./configure --with-fio=/path/to/fio/repo <other configuration options>
Finally, build SPDK:
make
Note to advanced users: These steps assume you're using the DPDK submodule. If you are using your own version of DPDK, the fio plugin requires that DPDK be compiled with -fPIC. You can compile DPDK with -fPIC by modifying your DPDK configuration file and adding the line:
EXTRA_CFLAGS=-fPIC
Usage
To use the SPDK fio plugin with fio, specify the plugin binary using LD_PRELOAD when running fio and set ioengine=spdk_bdev in the fio configuration file (see example_config.fio in the same directory as this README).
LD_PRELOAD=<path to spdk repo>/build/fio/spdk_bdev fio
The fio configuration file must contain one new parameter:
spdk_json_conf=./examples/bdev/fio_plugin/bdev.json
You can specify which block device to run against by setting the filename parameter to the block device name:
filename=Malloc0
Or for NVMe devices:
filename=Nvme0n1
fio by default forks a separate process for every job. It also supports just spawning a separate thread in the same process for every job. The SPDK fio plugin is limited to this latter thread usage model, so fio jobs must also specify thread=1 when using the SPDK fio plugin. The SPDK fio plugin supports multiple threads - in this case, the "1" just means "use thread mode".
fio also currently has a race condition on shutdown if dynamically loading the ioengine by specifying the engine's full path via the ioengine parameter - LD_PRELOAD is recommended to avoid this race condition.
When testing random workloads, it is recommended to set norandommap=1. fio's random map processing consumes extra CPU cycles which will degrade performance over time with the fio_plugin since all I/O are submitted and completed on a single CPU core.
Zoned Block Devices
SPDK has a zoned block device API (bdev_zone.h) which currently supports Open-channel SSDs, NVMe Zoned Namespaces (ZNS), and the virtual zoned block device SPDK module.
If you wish to run fio against a SPDK zoned block device, you can use the fio option:
zonemode=zbd
It is recommended to use a fio version newer than version 3.26, if using --numjobs > 1. If using --numjobs=1, fio version >= 3.23 should suffice.
See zbd_example.fio in this directory for a zoned block device example config.
Maximum Open Zones
Most zoned block devices have a resource constraint on the amount of zones which can be in an opened state at any point in time. It is very important to not exceed this limit.
You can control how many zones fio will keep in an open state by using the
--max_open_zones option.
If you use a fio version newer than 3.26, fio will automatically detect and set the proper value. If you use an old version of fio, make sure to provide the proper --max_open_zones value yourself.
Maximum Active Zones
Zoned block devices may also have a resource constraint on the number of zones that can be active at
any point in time. Unlike max_open_zones, fio currently does not manage this constraint, and
there is thus no option to limit it either.
Since the max active zones limit (by definition) has to be greater than or equal to the max open zones limit, the easiest way to work around that fio does not manage this constraint, is to start with a clean state each run (except for read-only workloads), by resetting all zones before fio starts running its jobs by using the engine option:
--initial_zone_reset=1
Zone Append
When running fio against a zoned block device you need to specify --iodepth=1 to avoid "Zone Invalid Write: The write to a zone was not at the write pointer." I/O errors. However, if your zoned block device supports Zone Append, you can use the engine option:
--zone_append=1
To send zone append commands instead of write commands to the zoned block device. When using zone append, you will be able to specify a --iodepth greater than 1.