perf intel-pt: Fix sync_switch

commit 63d8e38f6ae6c36dd5b5ba0e8c112e8861532ea2 upstream.

sync_switch is a facility to synchronize decoding more closely with the
point in the kernel when the context actually switched.

The flag when sync_switch is enabled was global to the decoding, whereas
it is really specific to the CPU.

The trace data for different CPUs is put on different queues, so add
sync_switch to the intel_pt_queue structure and use that in preference
to the global setting in the intel_pt structure.

That fixes problems decoding one CPU's trace because sync_switch was
disabled on a different CPU's queue.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1520431349-30689-3-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/tools/perf/util/intel-pt.c b/tools/perf/util/intel-pt.c
index 6a1367e20062a45b23bf8f783f33da076bd0c54c..d9573c1fa555d0316290301b5c114f465ad64f3e 100644 (file)
--- a/tools/perf/util/intel-pt.c
+++ b/tools/perf/util/intel-pt.c
@@ -145,6 +145,7 @@ struct intel_pt_queue {
        bool stop;
        bool step_through_buffers;
        bool use_buffer_pid_tid;
+       bool sync_switch;
        pid_t pid, tid;
        int cpu;
        int switch_state;
@@ -965,10 +966,12 @@ static int intel_pt_setup_queue(struct intel_pt *pt,
                        if (pt->timeless_decoding || !pt->have_sched_switch)
                                ptq->use_buffer_pid_tid = true;
                }
+
+               ptq->sync_switch = pt->sync_switch;
        }
 
        if (!ptq->on_heap &&
-           (!pt->sync_switch ||
+           (!ptq->sync_switch ||
             ptq->switch_state != INTEL_PT_SS_EXPECTING_SWITCH_EVENT)) {
                const struct intel_pt_state *state;
                int ret;
@@ -1552,7 +1555,7 @@ static int intel_pt_sample(struct intel_pt_queue *ptq)
        if (pt->synth_opts.last_branch)
                intel_pt_update_last_branch_rb(ptq);
 
-       if (!pt->sync_switch)
+       if (!ptq->sync_switch)
                return 0;
 
        if (intel_pt_is_switch_ip(ptq, state->to_ip)) {
@@ -1633,6 +1636,21 @@ static u64 intel_pt_switch_ip(struct intel_pt *pt, u64 *ptss_ip)
        return switch_ip;
 }
 
+static void intel_pt_enable_sync_switch(struct intel_pt *pt)
+{
+       unsigned int i;
+
+       pt->sync_switch = true;
+
+       for (i = 0; i < pt->queues.nr_queues; i++) {
+               struct auxtrace_queue *queue = &pt->queues.queue_array[i];
+               struct intel_pt_queue *ptq = queue->priv;
+
+               if (ptq)
+                       ptq->sync_switch = true;
+       }
+}
+
 static int intel_pt_run_decoder(struct intel_pt_queue *ptq, u64 *timestamp)
 {
        const struct intel_pt_state *state = ptq->state;
@@ -1649,7 +1667,7 @@ static int intel_pt_run_decoder(struct intel_pt_queue *ptq, u64 *timestamp)
                        if (pt->switch_ip) {
                                intel_pt_log("switch_ip: %"PRIx64" ptss_ip: %"PRIx64"\n",
                                             pt->switch_ip, pt->ptss_ip);
-                               pt->sync_switch = true;
+                               intel_pt_enable_sync_switch(pt);
                        }
                }
        }
@@ -1665,9 +1683,9 @@ static int intel_pt_run_decoder(struct intel_pt_queue *ptq, u64 *timestamp)
                if (state->err) {
                        if (state->err == INTEL_PT_ERR_NODATA)
                                return 1;
-                       if (pt->sync_switch &&
+                       if (ptq->sync_switch &&
                            state->from_ip >= pt->kernel_start) {
-                               pt->sync_switch = false;
+                               ptq->sync_switch = false;
                                intel_pt_next_tid(pt, ptq);
                        }
                        if (pt->synth_opts.errors) {
@@ -1693,7 +1711,7 @@ static int intel_pt_run_decoder(struct intel_pt_queue *ptq, u64 *timestamp)
                                     state->timestamp, state->est_timestamp);
                        ptq->timestamp = state->est_timestamp;
                /* Use estimated TSC in unknown switch state */
-               } else if (pt->sync_switch &&
+               } else if (ptq->sync_switch &&
                           ptq->switch_state == INTEL_PT_SS_UNKNOWN &&
                           intel_pt_is_switch_ip(ptq, state->to_ip) &&
                           ptq->next_tid == -1) {
@@ -1840,7 +1858,7 @@ static int intel_pt_sync_switch(struct intel_pt *pt, int cpu, pid_t tid,
                return 1;
 
        ptq = intel_pt_cpu_to_ptq(pt, cpu);
-       if (!ptq)
+       if (!ptq || !ptq->sync_switch)
                return 1;
 
        switch (ptq->switch_state) {