korg/linux
0
0
Fork 0
mirror of https://mirrors.bfsu.edu.cn/git/linux.git synced 2024-11-17 09:14:19 +08:00
Code Issues Packages Projects Releases Wiki Activity

perf/x86/intel: Support CPUID 10.ECX to disable fixed counters

Browse Source 
With Architectural Performance Monitoring Version 5, CPUID 10.ECX cpu
leaf indicates the fixed counter enumeration. This extends the previous
count to a bitmap which allows disabling even lower fixed counters.
It could be used by a Hypervisor.

The existing intel_ctrl variable is used to remember the bitmask of the
counters. All code that reads all counters is fixed to check this extra
bitmask.

Suggested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Originally-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/1611873611-156687-6-git-send-email-kan.liang@linux.intel.com
This commit is contained in:
Kan Liang 2021-01-28 14:40:11 -08:00 committed by Peter Zijlstra
parent 61b985e3e7
commit 32451614da
3 changed files with 36 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
arch/x86/events/core.c
View File

@ -255,6 +255,8 @@ static bool check_hw_exists(void)
if (ret)
goto msr_fail;
for (i = 0; i < x86_pmu.num_counters_fixed; i++) {
if (fixed_counter_disabled(i))
continue;
if (val & (0x03 << i*4)) {
bios_fail = 1;
val_fail = val;
@ -1531,6 +1533,8 @@ void perf_event_print_debug(void)
cpu, idx, prev_left);
}
for (idx = 0; idx < x86_pmu.num_counters_fixed; idx++) {
if (fixed_counter_disabled(idx))
continue;
rdmsrl(MSR_ARCH_PERFMON_FIXED_CTR0 + idx, pmc_count);
pr_info("CPU#%d: fixed-PMC%d count: %016llx\n",
@ -2012,7 +2016,9 @@ static int __init init_hw_perf_events(void)
pr_info("... generic registers: %d\n", x86_pmu.num_counters);
pr_info("... value mask: %016Lx\n", x86_pmu.cntval_mask);
pr_info("... max period: %016Lx\n", x86_pmu.max_period);
pr_info("... fixed-purpose events: %d\n", x86_pmu.num_counters_fixed);
pr_info("... fixed-purpose events: %lu\n",
hweight64((((1ULL << x86_pmu.num_counters_fixed) - 1)
<< INTEL_PMC_IDX_FIXED) & x86_pmu.intel_ctrl));
pr_info("... event mask: %016Lx\n", x86_pmu.intel_ctrl);
if (!x86_pmu.read)

34
arch/x86/events/intel/core.c
View File

@ -2723,8 +2723,11 @@ static void intel_pmu_reset(void)
wrmsrl_safe(x86_pmu_config_addr(idx), 0ull);
wrmsrl_safe(x86_pmu_event_addr(idx), 0ull);
}
for (idx = 0; idx < x86_pmu.num_counters_fixed; idx++)
for (idx = 0; idx < x86_pmu.num_counters_fixed; idx++) {
if (fixed_counter_disabled(idx))
continue;
wrmsrl_safe(MSR_ARCH_PERFMON_FIXED_CTR0 + idx, 0ull);
}
if (ds)
ds->bts_index = ds->bts_buffer_base;
@ -5042,7 +5045,7 @@ __init int intel_pmu_init(void)
union cpuid10_eax eax;
union cpuid10_ebx ebx;
struct event_constraint *c;
unsigned int unused;
unsigned int fixed_mask;
struct extra_reg *er;
bool pmem = false;
int version, i;
@ -5064,7 +5067,7 @@ __init int intel_pmu_init(void)
* Check whether the Architectural PerfMon supports
* Branch Misses Retired hw_event or not.
*/
cpuid(10, &eax.full, &ebx.full, &unused, &edx.full);
cpuid(10, &eax.full, &ebx.full, &fixed_mask, &edx.full);
if (eax.split.mask_length < ARCH_PERFMON_EVENTS_COUNT)
return -ENODEV;
@ -5088,12 +5091,15 @@ __init int intel_pmu_init(void)
* Quirk: v2 perfmon does not report fixed-purpose events, so
* assume at least 3 events, when not running in a hypervisor:
*/
if (version > 1) {
if (version > 1 && version < 5) {
int assume = 3 * !boot_cpu_has(X86_FEATURE_HYPERVISOR);
x86_pmu.num_counters_fixed =
max((int)edx.split.num_counters_fixed, assume);
}
fixed_mask = (1L << x86_pmu.num_counters_fixed) - 1;
} else if (version >= 5)
x86_pmu.num_counters_fixed = fls(fixed_mask);
if (boot_cpu_has(X86_FEATURE_PDCM)) {
u64 capabilities;
@ -5680,8 +5686,7 @@ __init int intel_pmu_init(void)
x86_pmu.num_counters_fixed = INTEL_PMC_MAX_FIXED;
}
x86_pmu.intel_ctrl |=
((1LL << x86_pmu.num_counters_fixed)-1) << INTEL_PMC_IDX_FIXED;
x86_pmu.intel_ctrl |= (u64)fixed_mask << INTEL_PMC_IDX_FIXED;
/* AnyThread may be deprecated on arch perfmon v5 or later */
if (x86_pmu.intel_cap.anythread_deprecated)
@ -5698,13 +5703,22 @@ __init int intel_pmu_init(void)
* events to the generic counters.
*/
if (c->idxmsk64 & INTEL_PMC_MSK_TOPDOWN) {
/*
* Disable topdown slots and metrics events,
* if slots event is not in CPUID.
*/
if (!(INTEL_PMC_MSK_FIXED_SLOTS & x86_pmu.intel_ctrl))
c->idxmsk64 = 0;
c->weight = hweight64(c->idxmsk64);
continue;
}
if (c->cmask == FIXED_EVENT_FLAGS
&& c->idxmsk64 != INTEL_PMC_MSK_FIXED_REF_CYCLES) {
c->idxmsk64 |= (1ULL << x86_pmu.num_counters) - 1;
if (c->cmask == FIXED_EVENT_FLAGS) {
/* Disabled fixed counters which are not in CPUID */
c->idxmsk64 &= x86_pmu.intel_ctrl;
if (c->idxmsk64 != INTEL_PMC_MSK_FIXED_REF_CYCLES)
c->idxmsk64 |= (1ULL << x86_pmu.num_counters) - 1;
}
c->idxmsk64 &=
~(~0ULL << (INTEL_PMC_IDX_FIXED + x86_pmu.num_counters_fixed));

5
arch/x86/events/perf_event.h
View File

@ -1068,6 +1068,11 @@ ssize_t events_sysfs_show(struct device *dev, struct device_attribute *attr,
ssize_t events_ht_sysfs_show(struct device *dev, struct device_attribute *attr,
char *page);
static inline bool fixed_counter_disabled(int i)
{
return !(x86_pmu.intel_ctrl >> (i + INTEL_PMC_IDX_FIXED));
}
#ifdef CONFIG_CPU_SUP_AMD
int amd_pmu_init(void);