e2a94f9ad3
While make has been deprecated for DPDK, it's still applicable for some example apps to be built standalone, this patch adjusts the guides to take that into consideration. Signed-off-by: Ciara Power <ciara.power@intel.com> Acked-by: Nicolas Chautru <nicolas.chautru@intel.com> Reviewed-by: Ferruh Yigit <ferruh.yigit@intel.com>
66 lines
2.2 KiB
ReStructuredText
66 lines
2.2 KiB
ReStructuredText
.. SPDX-License-Identifier: BSD-3-Clause
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Copyright(c) 2010-2017 Intel Corporation.
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Vhost_blk Sample Application
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=============================
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The vhost_blk sample application implemented a simple block device,
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which used as the backend of Qemu vhost-user-blk device. Users can extend
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the exist example to use other type of block device(e.g. AIO) besides
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memory based block device. Similar with vhost-user-net device, the sample
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application used domain socket to communicate with Qemu, and the virtio
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ring (split or packed format) was processed by vhost_blk sample application.
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The sample application reuse lots codes from SPDK(Storage Performance
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Development Kit, https://github.com/spdk/spdk) vhost-user-blk target,
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for DPDK vhost library used in storage area, user can take SPDK as
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reference as well.
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Testing steps
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-------------
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This section shows the steps how to start a VM with the block device as
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fast data path for critical application.
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Compiling the Application
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-------------------------
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To compile the sample application see :doc:`compiling`.
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The application is located in the ``examples`` sub-directory.
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You will also need to build DPDK both on the host and inside the guest
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Start the vhost_blk example
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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.. code-block:: console
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./dpdk-vhost_blk -m 1024
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.. _vhost_blk_app_run_vm:
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Start the VM
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~~~~~~~~~~~~
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.. code-block:: console
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qemu-system-x86_64 -machine accel=kvm \
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-m $mem -object memory-backend-file,id=mem,size=$mem,\
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mem-path=/dev/hugepages,share=on -numa node,memdev=mem \
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-drive file=os.img,if=none,id=disk \
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-device ide-hd,drive=disk,bootindex=0 \
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-chardev socket,id=char0,reconnect=1,path=/tmp/vhost.socket \
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-device vhost-user-blk-pci,packed=on,chardev=char0,num-queues=1 \
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...
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.. note::
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You must check whether your Qemu can support "vhost-user-blk" or not,
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Qemu v4.0 or newer version is required.
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reconnect=1 means live recovery support that qemu can reconnect vhost_blk
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after we restart vhost_blk example.
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packed=on means the device support packed ring but need the guest kernel
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version >= 5.0.
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Now Qemu commit 9bb73502321d46f4d320fa17aa38201445783fc4 both support the
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vhost-blk reconnect and packed ring.
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