950ecdc672
Unnecessary multiplexing is triggered when running an "instructions"
event on an MTL.
perf stat -e cpu_core/instructions/,cpu_core/instructions/ -a sleep 1
Performance counter stats for 'system wide':
115,489,000 cpu_core/instructions/ (50.02%)
127,433,777 cpu_core/instructions/ (49.98%)
1.002294504 seconds time elapsed
Linux architectural perf events, e.g., cycles and instructions, usually
have dedicated fixed counters. These events also have equivalent events
which can be used in the general-purpose counters. The counters are
precious. In the intel_pmu_check_event_constraints(), perf check/extend
the event constraints of these events. So these events can utilize both
fixed counters and general-purpose counters.
The following cleanup commit:
97588df87b ("perf/x86/intel: Add common intel_pmu_init_hybrid()")
forgot adding the intel_pmu_check_event_constraints() into update_pmu_cap().
The architectural perf events cannot utilize the general-purpose counters.
The code to check and update the counters, event constraints and
extra_regs is the same among hybrid systems. Move
intel_pmu_check_hybrid_pmus() to init_hybrid_pmu(), and
emove the duplicate check in update_pmu_cap().
Fixes: 97588df87b ("perf/x86/intel: Add common intel_pmu_init_hybrid()")
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20230911135128.2322833-1-kan.liang@linux.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.