d6f328bfeb
Apply backpressure to hogs that emit requests faster than the GPU can process them by waiting for their ring to be less than half-full before proceeding with taking the struct_mutex. This is a gross hack to apply throttling backpressure, the long term goal is to remove the struct_mutex contention so that each client naturally waits, preferably in an asynchronous, nonblocking fashion (pipelined operations for the win), for their own resources and never blocks another client within the driver at least. (Realtime priority goals would extend to ensuring that resource contention favours high priority clients as well.) This patch only limits excessive request production and does not attempt to throttle clients that block waiting for eviction (either global GTT or system memory) or any other global resources, see above for the long term goal. No microbenchmarks are harmed (to the best of my knowledge). Testcase: igt/gem_exec_schedule/pi-ringfull-* Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: John Harrison <John.C.Harrison@Intel.com> Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190207071829.5574-1-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.