linuxdebug/tools/perf/util/smt.c

38 lines
916 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(const struct cpu_topology *topology)
{
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(topology);
cached = true;
return cached_result;
}
bool core_wide(bool system_wide, const char *user_requested_cpu_list,
const struct cpu_topology *topology)
{
/* 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(topology))
return true;
return cpu_topology__core_wide(topology, user_requested_cpu_list);
}