eBPF programs would like access to the (perf) event enabled and
running times along with the event value, such that they can deal with
event multiplexing (among other things).
This patch extends the interface; a future eBPF patch will utilize
the new functionality.
[ Note, there's a same-content commit with a poor changelog and a meaningless
title in the networking tree as well - but we need this change for subsequent
perf work, so apply it here as well, with a proper changelog. Hopefully Git
will be able to sort out this somewhat messy workflow, if there are no other,
conflicting changes to these files. ]
Signed-off-by: Yonghong Song <yhs@fb.com>
[ Rewrote the changelog. ]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <ast@fb.com>
Cc: <daniel@iogearbox.net>
Cc: <rostedt@goodmis.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: David S. Miller <davem@davemloft.net>
Link: http://lkml.kernel.org/r/20171005161923.332790-2-yhs@fb.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
struct bpf_perf_event_data_kern {
struct pt_regs *regs;
struct perf_sample_data *data;
+ struct perf_event *event;
};
#ifdef CONFIG_CGROUP_PERF
void *context);
extern void perf_pmu_migrate_context(struct pmu *pmu,
int src_cpu, int dst_cpu);
-int perf_event_read_local(struct perf_event *event, u64 *value);
+int perf_event_read_local(struct perf_event *event, u64 *value,
+ u64 *enabled, u64 *running);
extern u64 perf_event_read_value(struct perf_event *event,
u64 *enabled, u64 *running);
{
return ERR_PTR(-EINVAL);
}
-static inline int perf_event_read_local(struct perf_event *event, u64 *value)
+static inline int perf_event_read_local(struct perf_event *event, u64 *value,
+ u64 *enabled, u64 *running)
{
return -EINVAL;
}
ee = ERR_PTR(-EOPNOTSUPP);
event = perf_file->private_data;
- if (perf_event_read_local(event, &value) == -EOPNOTSUPP)
+ if (perf_event_read_local(event, &value, NULL, NULL) == -EOPNOTSUPP)
goto err_out;
ee = bpf_event_entry_gen(perf_file, map_file);
* will not be local and we cannot read them atomically
* - must not have a pmu::count method
*/
-int perf_event_read_local(struct perf_event *event, u64 *value)
+int perf_event_read_local(struct perf_event *event, u64 *value,
+ u64 *enabled, u64 *running)
{
unsigned long flags;
int ret = 0;
+ u64 now;
/*
* Disabling interrupts avoids all counter scheduling (context
goto out;
}
+ now = event->shadow_ctx_time + perf_clock();
+ if (enabled)
+ *enabled = now - event->tstamp_enabled;
/*
* If the event is currently on this CPU, its either a per-task event,
* or local to this CPU. Furthermore it means its ACTIVE (otherwise
* oncpu == -1).
*/
- if (event->oncpu == smp_processor_id())
+ if (event->oncpu == smp_processor_id()) {
event->pmu->read(event);
+ if (running)
+ *running = now - event->tstamp_running;
+ } else if (running) {
+ *running = event->total_time_running;
+ }
*value = local64_read(&event->count);
out:
struct bpf_perf_event_data_kern ctx = {
.data = data,
.regs = regs,
+ .event = event,
};
int ret = 0;
if (!ee)
return -ENOENT;
- err = perf_event_read_local(ee->event, &value);
+ err = perf_event_read_local(ee->event, &value, NULL, NULL);
/*
* this api is ugly since we miss [-22..-2] range of valid
* counter values, but that's uapi