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47008bb51c
Currently, the virtio core will perform a dma operation for each
buffer. Although, the same page may be operated multiple times.
In premapped mod, we can perform only one dma operation for the pages of
the alloc frag. This is beneficial for the iommu device.
kernel command line: intel_iommu=on iommu.passthrough=0
| strict=0 | strict=1
Before | 775496pps | 428614pps
After | 1109316pps | 742853pps
In the 6.11, we disabled this feature because a regress [1].
Now, we fix the problem and re-enable it.
[1]: http://lore.kernel.org/all/8b20cc28-45a9-4643-8e87-ba164a540c0a@oracle.com
Tested-by: Darren Kenny <darren.kenny@oracle.com>
Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.