mainlining shenanigans
73ef8f3382
The original design and current implementation of the PFVF protocol expects the sender to both acquire and relinquish the ownership of the shared CSR by setting and clearing the "in use" pattern on the remote half of the register when sending a message. This happens regardless of the acknowledgment of the reception, to guarantee changes, including collisions, are surely detected. However, in the case of a request that requires a response, collisions can also be detected by the lack of a reply. This can be exploited to speed up and simplify the above behaviour, letting the receiver both acknowledge the message and release the CSR in a single transaction: 1) the sender can return as soon as the message has been acknowledged 2) the receiver doesn't have to wait long before acquiring ownership of the CSR for the response message, greatly improving the overall throughput. Howerver, this improvement cannot be leveraged for fire-and-forget notifications, as it would be impossible for the sender to clearly distinguish between a collision and an ack immediately followed by a new message. This patch implements this optimization in a new version of the protocol (v3), which applies the fast-ack logic only whenever possible and guarantees backward compatibility with older versions. For requests, a new retry loop guarantees a correct behaviour. Signed-off-by: Marco Chiappero <marco.chiappero@intel.com> Reviewed-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com> Reviewed-by: Fiona Trahe <fiona.trahe@intel.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> |
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| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
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 Restructured Text 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.