perf/x86: Add dynamic constraint

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More and more features require a dynamic event constraint, e.g., branch
counter logging, auto counter reload, Arch PEBS, etc.

Add a generic flag, PMU_FL_DYN_CONSTRAINT, to indicate the case. It
avoids keeping adding the individual flag in intel_cpuc_prepare().

Add a variable dyn_constraint in the struct hw_perf_event to track the
dynamic constraint of the event. Apply it if it's updated.

Apply the generic dynamic constraint for branch counter logging.
Many features on and after V6 require dynamic constraint. So
unconditionally set the flag for V6+.

Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Thomas Falcon <thomas.falcon@intel.com>
Link: https://lkml.kernel.org/r/20250327195217.2683619-2-kan.liang@linux.intel.com

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This commit is contained in:

Kan Liang 2025-03-27 12:52:13 -07:00 • committed by Peter Zijlstra

parent da916e96e2

commit 4dfe3232cc

5 changed files with 19 additions and 7 deletions

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1

arch/x86/events/core.c

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21

arch/x86/events/intel/core.c

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arch/x86/events/intel/lbr.c

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arch/x86/events/perf_event.h

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include/linux/perf_event.h

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