5aa857db54
GPU accumulates the context runtime in a 32 bit counter - CTX_TIMESTAMP in the context image. This value is saved/restored on context switches. KMD accumulates these values into a 64 bit counter taking care of any overflows as needed. This count provides the basis for client specific busyness in the fdinfo interface. KMD accumulation happens just before the context is unpinned and when context switches out. This works for execlist back-end since execlist scheduling has visibility into context switches. With GuC mode, KMD does not have visibility into context switches and this counter is accumulated only when context is unpinned. Context is unpinned once the context scheduling is successfully disabled. Disabling context scheduling is an asynchronous operation. Also if a context is servicing frequent requests, scheduling may never be disabled on it. For GuC mode, since updates to the context runtime may be delayed, add hooks to update the context runtime in a worker thread as well as when a user queries for it. Limitation: - If a context is never switched out or runs for a long period of time, the runtime value of CTX_TIMESTAMP may never be updated, so the counter value may be unreliable. This patch does not support such cases. Such support must be available from the GuC FW and it is WIP. This patch is an extract from previous work authored by John/Umesh here - https://patchwork.freedesktop.org/patch/496441/?series=105085&rev=4 v2: (Ashutosh) - Drop COPS_RUNTIME_ACTIVE_TOTAL - s/guc_context_update_clks/__guc_context_update_stats - Pin context before accessing in guc_timestamp_ping - In guc_context_unpin, use spinlock to serialize access to runtime stats Signed-off-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com> Co-developed-by: John Harrison <John.C.Harrison@Intel.com> Signed-off-by: John Harrison <John.C.Harrison@Intel.com> Reviewed-by: Ashutosh Dixit <ashutosh.dixit@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20230427224705.2785566-2-umesh.nerlige.ramappa@intel.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 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.