a724ec8296
This expands generic branch type classification by adding two more entries there in i.e system error and not in transaction. This also updates the x86 implementation to process X86_BR_NO_TX records as appropriate. This changes branch types reported to user space on x86 platform but it should not be a problem. The possible scenarios and impacts are enumerated here. -------------------------------------------------------------------------- | kernel | perf tool | Impact | -------------------------------------------------------------------------- | old | old | Works as before | -------------------------------------------------------------------------- | old | new | PERF_BR_UNKNOWN is processed | -------------------------------------------------------------------------- | new | old | PERF_BR_NO_TX is blocked via old PERF_BR_MAX | -------------------------------------------------------------------------- | new | new | PERF_BR_NO_TX is recognized | -------------------------------------------------------------------------- When PERF_BR_NO_TX is blocked via old PERF_BR_MAX (new kernel with old perf tool) the user space might throw up an warning complaining about an unrecognized branch types being reported, but it's expected. PERF_BR_SERROR & PERF_BR_NO_TX branch types will be used for BRBE implementation on arm64 platform. PERF_BR_NO_TX complements 'abort' and 'in_tx' elements in perf_branch_entry which represent other transaction states for a given branch record. Because this completes the transaction state classification. Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: James Clark <james.clark@arm.com> Link: https://lkml.kernel.org/r/20220824044822.70230-2-anshuman.khandual@arm.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.