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tools/power turbostat: Enable non-privileged users to read sysfs counters

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A group of counters called "sysfs" displays software
C-state request counts and resulting perceived C-state residency.

They are not built-in counters that turbostat knows about ahead of time,
rather they are discovered in sysfs when turbostat starts.

Thus, they are added dynamically, using the same interface
as user-added MSR counters.

When turbostat enters "no-msr" mode, such as when running as a
non-privileged user, it clears all added counters.

Updating that to clear only actual MSR added counters
allows regular users to see the sysfs counters.

[lenb: commit message]

Signed-off-by: Patryk Wlazlyn <patryk.wlazlyn@linux.intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
This commit is contained in:
Patryk Wlazlyn 2024-04-25 17:54:18 +02:00 committed by Len Brown
parent d3e6f62538
commit 0e39702fbb
1 changed files with 31 additions and 25 deletions
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56
tools/power/x86/turbostat/turbostat.c
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@ -1377,36 +1377,42 @@ struct sys_counters {
struct msr_counter *pp;
} sys;
void free_sys_counters(void)
static size_t free_msr_counters_(struct msr_counter **pp)
{
struct msr_counter *p = sys.tp, *pnext = NULL;
struct msr_counter *p = NULL;
size_t num_freed = 0;
while (p) {
pnext = p->next;
free(p);
p = pnext;
while (*pp) {
p = *pp;
if (p->msr_num != 0) {
*pp = p->next;
free(p);
++num_freed;
continue;
}
pp = &p->next;
}
p = sys.cp, pnext = NULL;
while (p) {
pnext = p->next;
free(p);
p = pnext;
}
return num_freed;
}
p = sys.pp, pnext = NULL;
while (p) {
pnext = p->next;
free(p);
p = pnext;
}
/*
* Free all added counters accessed via msr.
*/
static void free_sys_msr_counters(void)
{
/* Thread counters */
sys.added_thread_counters -= free_msr_counters_(&sys.tp);
sys.added_thread_counters = 0;
sys.added_core_counters = 0;
sys.added_package_counters = 0;
sys.tp = NULL;
sys.cp = NULL;
sys.pp = NULL;
/* Core counters */
sys.added_core_counters -= free_msr_counters_(&sys.cp);
/* Package counters */
sys.added_package_counters -= free_msr_counters_(&sys.pp);
}
struct system_summary {
@ -1566,7 +1572,7 @@ static void bic_disable_msr_access(void)
bic_enabled &= ~bic_msrs;
free_sys_counters();
free_sys_msr_counters();
}
static long perf_event_open(struct perf_event_attr *hw_event, pid_t pid, int cpu, int group_fd, unsigned long flags)