linux/tools/perf/util/smt.c
Ian Rogers 207f7df727 perf expr: Make the online topology accessible globally
Knowing the topology of online CPUs is useful for more than just expr
literals. Move to a global function that caches the value. An
additional upside is that this may also avoid computing the CPU
topology in some situations.

Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexandre Torgue <alexandre.torgue@foss.st.com>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Cc: Caleb Biggers <caleb.biggers@intel.com>
Cc: Eduard Zingerman <eddyz87@gmail.com>
Cc: Florian Fischer <florian.fischer@muhq.space>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@arm.com>
Cc: Jing Zhang <renyu.zj@linux.alibaba.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Garry <john.g.garry@oracle.com>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Perry Taylor <perry.taylor@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Cc: Sandipan Das <sandipan.das@amd.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Suzuki Poulouse <suzuki.poulose@arm.com>
Cc: Xing Zhengjun <zhengjun.xing@linux.intel.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-stm32@st-md-mailman.stormreply.com
Link: https://lore.kernel.org/r/20230219092848.639226-8-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2023-02-19 08:03:12 -03:00

37 lines
850 B
C

// SPDX-License-Identifier: GPL-2.0-only
#include <string.h>
#include "api/fs/fs.h"
#include "cputopo.h"
#include "smt.h"
bool smt_on(void)
{
static bool cached;
static bool cached_result;
int fs_value;
if (cached)
return cached_result;
if (sysfs__read_int("devices/system/cpu/smt/active", &fs_value) >= 0)
cached_result = (fs_value == 1);
else
cached_result = cpu_topology__smt_on(online_topology());
cached = true;
return cached_result;
}
bool core_wide(bool system_wide, const char *user_requested_cpu_list)
{
/* If not everything running on a core is being recorded then we can't use core_wide. */
if (!system_wide)
return false;
/* Cheap case that SMT is disabled and therefore we're inherently core_wide. */
if (!smt_on())
return true;
return cpu_topology__core_wide(online_topology(), user_requested_cpu_list);
}