Commit 63d8e38f authored by Adrian Hunter's avatar Adrian Hunter Committed by Arnaldo Carvalho de Melo
Browse files

perf intel-pt: Fix sync_switch 



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: default avatarAdrian 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: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 117db4b2

tools/perf/util/intel-pt.c

+25 −7
Original line number Diff line number Diff line
@@ -143,6 +143,7 @@ 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;
@@ -963,10 +964,12 @@ 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;
@@ -1549,7 +1552,7 @@ 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)) {
@@ -1630,6 +1633,21 @@ 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;
@@ -1646,7 +1664,7 @@ 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);

			}

		}

	}
@@ -1662,9 +1680,9 @@ 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) {
@@ -1690,7 +1708,7 @@ 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) {
@@ -1837,7 +1855,7 @@ 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) {

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