perf: Extend the mmap control page with time (TSC) fields
[~shefty/rdma-dev.git] / kernel / events / core.c
index dcd4049e92fcf1832aecb50ff5dfa94245108293..3a9c7d81afbfdbb1a678436b32acb8279d9ad8d5 100644 (file)
@@ -3220,17 +3220,22 @@ static int perf_event_index(struct perf_event *event)
 }
 
 static void calc_timer_values(struct perf_event *event,
+                               u64 *now,
                                u64 *enabled,
                                u64 *running)
 {
-       u64 now, ctx_time;
+       u64 ctx_time;
 
-       now = perf_clock();
-       ctx_time = event->shadow_ctx_time + now;
+       *now = perf_clock();
+       ctx_time = event->shadow_ctx_time + *now;
        *enabled = ctx_time - event->tstamp_enabled;
        *running = ctx_time - event->tstamp_running;
 }
 
+void __weak perf_update_user_clock(struct perf_event_mmap_page *userpg, u64 now)
+{
+}
+
 /*
  * Callers need to ensure there can be no nesting of this function, otherwise
  * the seqlock logic goes bad. We can not serialize this because the arch
@@ -3240,7 +3245,7 @@ void perf_event_update_userpage(struct perf_event *event)
 {
        struct perf_event_mmap_page *userpg;
        struct ring_buffer *rb;
-       u64 enabled, running;
+       u64 enabled, running, now;
 
        rcu_read_lock();
        /*
@@ -3252,7 +3257,7 @@ void perf_event_update_userpage(struct perf_event *event)
         * because of locking issue as we can be called in
         * NMI context
         */
-       calc_timer_values(event, &enabled, &running);
+       calc_timer_values(event, &now, &enabled, &running);
        rb = rcu_dereference(event->rb);
        if (!rb)
                goto unlock;
@@ -3277,6 +3282,8 @@ void perf_event_update_userpage(struct perf_event *event)
        userpg->time_running = running +
                        atomic64_read(&event->child_total_time_running);
 
+       perf_update_user_clock(userpg, now);
+
        barrier();
        ++userpg->lock;
        preempt_enable();
@@ -3763,7 +3770,7 @@ static void perf_output_read_group(struct perf_output_handle *handle,
 static void perf_output_read(struct perf_output_handle *handle,
                             struct perf_event *event)
 {
-       u64 enabled = 0, running = 0;
+       u64 enabled = 0, running = 0, now;
        u64 read_format = event->attr.read_format;
 
        /*
@@ -3776,7 +3783,7 @@ static void perf_output_read(struct perf_output_handle *handle,
         * NMI context
         */
        if (read_format & PERF_FORMAT_TOTAL_TIMES)
-               calc_timer_values(event, &enabled, &running);
+               calc_timer_values(event, &now, &enabled, &running);
 
        if (event->attr.read_format & PERF_FORMAT_GROUP)
                perf_output_read_group(handle, event, enabled, running);