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b1c5efbfd9
Now that legacy hardware and cache events are in json, having the lexer match the specific event is no longer necessary and generic PMU parsing can take place. Because of this remove the specific term parsing, event adding, and passing of alternate_hw_config which was now always PERF_COUNT_HW_MAX. This mirrors a similar change for software events in commit6e9fa4131a("perf parse-events: Remove non-json software events"). With no hard coded legacy hardware or cache events the wild card, case insensitivity, etc. is consistent for events. This does, however, mean events like cycles will wild card against all PMUs. A change does the same was originally posted and merged from: https://lore.kernel.org/r/20240416061533.921723-10-irogers@google.com and reverted by Linus in commit4f1b067359("Revert "perf parse-events: Prefer sysfs/JSON hardware events over legacy"") due to his dislike for the cycles behavior on ARM. Earlier patches in this series make perf record event opening failures non-fatal and hide the cycles event's failure to open on ARM in perf record, so it is expected the behavior will now be transparent in perf record. perf stat with a cycles event will wildcard open the event on all PMUs. As cycles is a "default event", the perf stat behavior for default events was updated to only open them on core/software PMUs. The change to support legacy events with PMUs was done to clean up Intel's hybrid PMU implementation. Having sysfs/json events with increased priority to legacy was requested by Mark Rutland <mark.rutland@arm.com> to fix Apple-M PMU issues wrt broken legacy events on that PMU. It was requested that RISC-V be able to add events to the perf tool json so the PMU driver didn't need to map legacy events to config encodings: https://lore.kernel.org/lkml/20240217005738.3744121-1-atishp@rivosinc.com/ A previous series of patches decreasing legacy hardware event priorities was posted in: https://lore.kernel.org/lkml/20250416045117.876775-1-irogers@google.com/ Namhyung Kim <namhyung@kernel.org> mentioned that hardware and software events can be implemented similarly: https://lore.kernel.org/lkml/aIJmJns2lopxf3EK@google.com/ Tested-by: Thomas Richter <tmricht@linux.ibm.com> Signed-off-by: Ian Rogers <irogers@google.com> Tested-by: James Clark <james.clark@linaro.org> Signed-off-by: Namhyung Kim <namhyung@kernel.org>
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 reStructuredText 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.