d1df41eb72
We're about to introduce an options to open the perf stream, giving the user ability to configure how often it wants the kernel to poll the OA registers for available data. Right now the workaround against the OA tail pointer race condition requires at least twice the internal kernel polling timer to make any data available. This changes introduce checks on the OA data written into the circular buffer to make as much data as possible available on the first iteration of the polling timer. v2: Use OA_TAKEN macro without the gtt_offset (Lionel) v3: (Umesh) - Rebase - Change report to report32 from below review https://patchwork.freedesktop.org/patch/330704/?series=66697&rev=1 v4: (Ashutosh, Lionel) - Fix checkpatch errors - Fix aging_timestamp initialization - Check for only one valid landed report - Fix check for unlanded report v5: (Ashutosh) - Fix bug in accurately determining landed report. - Optimize the check for landed reports by going as far as the previously determined aged tail. Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com> Signed-off-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com> Reviewed-by: Ashutosh Dixit <ashutosh.dixit@intel.com> Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200324185457.14635-2-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.