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It can be difficult to figure out for user programs what features the x86 CPU PMU driver actually supports. Currently it requires grepping in dmesg, but dmesg is not always available. This adds a caps directory to /sys/bus/event_source/devices/cpu/, similar to the caps already used on intel_pt, which can be used to discover the available capabilities cleanly. Three capabilities are defined: - pmu_name: Underlying CPU name known to the driver - max_precise: Max precise level supported - branches: Known depth of LBR. Example: % grep . /sys/bus/event_source/devices/cpu/caps/* /sys/bus/event_source/devices/cpu/caps/branches:32 /sys/bus/event_source/devices/cpu/caps/max_precise:3 /sys/bus/event_source/devices/cpu/caps/pmu_name:skylake Signed-off-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20170822185201.9261-3-andi@firstfloor.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. 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.