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    Subject[PATCH 4.9 05/66] perf intel-pt: Fix sync_switch
    Date
    4.9-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Adrian Hunter <adrian.hunter@intel.com>

    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>

    ---
    tools/perf/util/intel-pt.c | 32 +++++++++++++++++++++++++-------
    1 file changed, 25 insertions(+), 7 deletions(-)

    --- a/tools/perf/util/intel-pt.c
    +++ b/tools/perf/util/intel-pt.c
    @@ -131,6 +131,7 @@ 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;
    @@ -931,10 +932,12 @@ static int intel_pt_setup_queue(struct i
    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;
    @@ -1336,7 +1339,7 @@ static int intel_pt_sample(struct intel_
    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)) {
    @@ -1417,6 +1420,21 @@ static u64 intel_pt_switch_ip(struct int
    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;
    @@ -1433,7 +1451,7 @@ static int intel_pt_run_decoder(struct i
    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);
    }
    }
    }
    @@ -1449,9 +1467,9 @@ static int intel_pt_run_decoder(struct i
    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) {
    @@ -1477,7 +1495,7 @@ static int intel_pt_run_decoder(struct i
    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) {
    @@ -1624,7 +1642,7 @@ static int intel_pt_sync_switch(struct i
    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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