perf topology: Add core_wide

It is possible to optimize metrics when all SMT threads (CPUs) on a
core are measuring events in system wide mode. For example, TMA
metrics defines CORE_CLKS for Sandybrdige as:

if SMT is disabled:
  CPU_CLK_UNHALTED.THREAD
if SMT is enabled and recording on all SMT threads:
  CPU_CLK_UNHALTED.THREAD_ANY / 2
if SMT is enabled and not recording on all SMT threads:
  (CPU_CLK_UNHALTED.THREAD/2)*
  (1+CPU_CLK_UNHALTED.ONE_THREAD_ACTIVE/CPU_CLK_UNHALTED.REF_XCLK )

That is two more events are necessary when not gathering counts on all
SMT threads. To distinguish all SMT threads on a core vs system wide
(all CPUs) call the new property core wide.  Add a core wide test that
determines the property from user requested CPUs, the topology and
system wide. System wide is required as other processes running on a
SMT thread will change the counts.

Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Ahmad Yasin <ahmad.yasin@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Caleb Biggers <caleb.biggers@intel.com>
Cc: Florian Fischer <florian.fischer@muhq.space>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@arm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Garry <john.garry@huawei.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Kshipra Bopardikar <kshipra.bopardikar@intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Miaoqian Lin <linmq006@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Perry Taylor <perry.taylor@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Cc: Xing Zhengjun <zhengjun.xing@linux.intel.com>
Link: https://lore.kernel.org/r/20220831174926.579643-5-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/tools/perf/util/cputopo.h b/tools/perf/util/cputopo.h
index 469db775a13c..969e5920a00e 100644
--- a/tools/perf/util/cputopo.h
+++ b/tools/perf/util/cputopo.h
@@ -60,6 +60,9 @@ struct cpu_topology *cpu_topology__new(void);
 void cpu_topology__delete(struct cpu_topology *tp);
 /* Determine from the core list whether SMT was enabled. */
 bool cpu_topology__smt_on(const struct cpu_topology *topology);
+/* Are the sets of SMT siblings all enabled or all disabled in user_requested_cpus. */
+bool cpu_topology__core_wide(const struct cpu_topology *topology,
+			     const char *user_requested_cpu_list);
 
 struct numa_topology *numa_topology__new(void);
 void numa_topology__delete(struct numa_topology *tp);