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There is a desire to split a task onto two engines and have them run at the same time, e.g. scanline interleaving to spread the workload evenly. Through the use of the out-fence from the first execbuf, we can coordinate secondary execbuf to only become ready simultaneously with the first, so that with all things idle the second execbufs are executed in parallel with the first. The key difference here between the new EXEC_FENCE_SUBMIT and the existing EXEC_FENCE_IN is that the in-fence waits for the completion of the first request (so that all of its rendering results are visible to the second execbuf, the more common userspace fence requirement). Since we only have a single input fence slot, userspace cannot mix an in-fence and a submit-fence. It has to use one or the other! This is not such a harsh requirement, since by virtue of the submit-fence, the secondary execbuf inherit all of the dependencies from the first request, and for the application the dependencies should be common between the primary and secondary execbuf. Suggested-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Testcase: igt/gem_exec_fence/parallel Link: https://github.com/intel/media-driver/pull/546 Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190521211134.16117-10-chris@chris-wilson.co.uk
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.