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authorKan Liang <kan.liang@linux.intel.com>2021-04-12 07:31:01 -0700
committerPeter Zijlstra <peterz@infradead.org>2021-04-19 20:03:29 +0200
commit55bcf6ef314ae8ba81bcd74aa760247b635ed47b (patch)
tree7772dd2ae3b660a5bc1e0368024675f2acc135b5 /kernel/events
parentf83d2f91d2590318e083d05bd7b1beda2489050e (diff)
downloadlinux-55bcf6ef314ae8ba81bcd74aa760247b635ed47b.tar.bz2
perf: Extend PERF_TYPE_HARDWARE and PERF_TYPE_HW_CACHE
Current Hardware events and Hardware cache events have special perf types, PERF_TYPE_HARDWARE and PERF_TYPE_HW_CACHE. The two types don't pass the PMU type in the user interface. For a hybrid system, the perf subsystem doesn't know which PMU the events belong to. The first capable PMU will always be assigned to the events. The events never get a chance to run on the other capable PMUs. Extend the two types to become PMU aware types. The PMU type ID is stored at attr.config[63:32]. Add a new PMU capability, PERF_PMU_CAP_EXTENDED_HW_TYPE, to indicate a PMU which supports the extended PERF_TYPE_HARDWARE and PERF_TYPE_HW_CACHE. The PMU type is only required when searching a specific PMU. The PMU specific codes will only be interested in the 'real' config value, which is stored in the low 32 bit of the event->attr.config. Update the event->attr.config in the generic code, so the PMU specific codes don't need to calculate it separately. If a user specifies a PMU type, but the PMU doesn't support the extended type, error out. If an event cannot be initialized in a PMU specified by a user, error out immediately. Perf should not try to open it on other PMUs. The new PMU capability is only set for the X86 hybrid PMUs for now. Other architectures, e.g., ARM, may need it as well. The support on ARM may be implemented later separately. Suggested-by: Peter Zijlstra (Intel) <peterz@infradead.org> 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/1618237865-33448-22-git-send-email-kan.liang@linux.intel.com
Diffstat (limited to 'kernel/events')
-rw-r--r--kernel/events/core.c19
1 files changed, 16 insertions, 3 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 6f0723c711a9..928b166d888e 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -11220,6 +11220,7 @@ static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
static struct pmu *perf_init_event(struct perf_event *event)
{
+ bool extended_type = false;
int idx, type, ret;
struct pmu *pmu;
@@ -11238,16 +11239,27 @@ static struct pmu *perf_init_event(struct perf_event *event)
* are often aliases for PERF_TYPE_RAW.
*/
type = event->attr.type;
- if (type == PERF_TYPE_HARDWARE || type == PERF_TYPE_HW_CACHE)
- type = PERF_TYPE_RAW;
+ if (type == PERF_TYPE_HARDWARE || type == PERF_TYPE_HW_CACHE) {
+ type = event->attr.config >> PERF_PMU_TYPE_SHIFT;
+ if (!type) {
+ type = PERF_TYPE_RAW;
+ } else {
+ extended_type = true;
+ event->attr.config &= PERF_HW_EVENT_MASK;
+ }
+ }
again:
rcu_read_lock();
pmu = idr_find(&pmu_idr, type);
rcu_read_unlock();
if (pmu) {
+ if (event->attr.type != type && type != PERF_TYPE_RAW &&
+ !(pmu->capabilities & PERF_PMU_CAP_EXTENDED_HW_TYPE))
+ goto fail;
+
ret = perf_try_init_event(pmu, event);
- if (ret == -ENOENT && event->attr.type != type) {
+ if (ret == -ENOENT && event->attr.type != type && !extended_type) {
type = event->attr.type;
goto again;
}
@@ -11268,6 +11280,7 @@ again:
goto unlock;
}
}
+fail:
pmu = ERR_PTR(-ENOENT);
unlock:
srcu_read_unlock(&pmus_srcu, idx);