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Because of its shallow queues and limited reordering ability, the i.MX6Q memory controller likes AXI bursts of consecutive addresses a lot. To optimize memory access performance, lock the IPU scanout channels for a number of burst accesses each, before switching to the next channel. The burst size and length of a locked burst chain are chosen not to overshoot the stride. Enabling the 8-burst channel lock on a single 1920x1080@60Hz RGBx scanout (474 MiB/s of 64-byte IPU memory read accesses) reduces the reported memory controller busy cycles from 46% to below 28% on an otherwise idle i.MX6Q. Tested-by: Lucas Stach <l.stach@pengutronix.de> Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. 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.