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SubjectRe: [PATCH 2/6] perf cs-etm: Split setup and timestamp search functions
On Tue, Jul 13, 2021 at 04:40:04PM +0100, James Clark wrote:
> This refactoring has some benefits:
> * Decoding is done to find the timestamp. If we want to print errors
> when maps aren't available, then doing it from cs_etm__setup_queue()
> may cause warnings to be printed.
> * The cs_etm__setup_queue() flow is shared between timed and timeless
> modes, so it needs to be guarded by an if statement which can now
> be removed.
> * Allows moving the setup queues function earlier.
> * If data was piped in, then not all queues would be filled so it
> wouldn't have worked properly anyway. Now it waits for flush so
> data in all queues will be available.
>
> The motivation for this is to decouple setup functions with ones that
> involve decoding. That way we can move the setup function earlier when
> the formatted/unformatted trace information is available.
>
> Signed-off-by: James Clark <james.clark@arm.com>
> ---
> tools/perf/util/cs-etm.c | 41 ++++++++++++++++++++++++++++------------
> 1 file changed, 29 insertions(+), 12 deletions(-)

Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>

>
> diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c
> index 4c69ef391f60..426e99c07ca9 100644
> --- a/tools/perf/util/cs-etm.c
> +++ b/tools/perf/util/cs-etm.c
> @@ -809,29 +809,32 @@ static int cs_etm__setup_queue(struct cs_etm_auxtrace *etm,
> struct auxtrace_queue *queue,
> unsigned int queue_nr)
> {
> - int ret = 0;
> - unsigned int cs_queue_nr;
> - u8 trace_chan_id;
> - u64 cs_timestamp;
> struct cs_etm_queue *etmq = queue->priv;
>
> if (list_empty(&queue->head) || etmq)
> - goto out;
> + return 0;
>
> etmq = cs_etm__alloc_queue(etm);
>
> - if (!etmq) {
> - ret = -ENOMEM;
> - goto out;
> - }
> + if (!etmq)
> + return -ENOMEM;
>
> queue->priv = etmq;
> etmq->etm = etm;
> etmq->queue_nr = queue_nr;
> etmq->offset = 0;
>
> - if (etm->timeless_decoding)
> - goto out;
> + return 0;
> +}
> +
> +static int cs_etm__queue_first_cs_timestamp(struct cs_etm_auxtrace *etm,
> + struct cs_etm_queue *etmq,
> + unsigned int queue_nr)
> +{
> + int ret = 0;
> + unsigned int cs_queue_nr;
> + u8 trace_chan_id;
> + u64 cs_timestamp;
>
> /*
> * We are under a CPU-wide trace scenario. As such we need to know
> @@ -2218,13 +2221,27 @@ static int cs_etm__process_timeless_queues(struct cs_etm_auxtrace *etm,
> static int cs_etm__process_queues(struct cs_etm_auxtrace *etm)
> {
> int ret = 0;
> - unsigned int cs_queue_nr, queue_nr;
> + unsigned int cs_queue_nr, queue_nr, i;
> u8 trace_chan_id;
> u64 cs_timestamp;
> struct auxtrace_queue *queue;
> struct cs_etm_queue *etmq;
> struct cs_etm_traceid_queue *tidq;
>
> + /*
> + * Pre-populate the heap with one entry from each queue so that we can
> + * start processing in time order across all queues.
> + */
> + for (i = 0; i < etm->queues.nr_queues; i++) {
> + etmq = etm->queues.queue_array[i].priv;
> + if (!etmq)
> + continue;
> +
> + ret = cs_etm__queue_first_cs_timestamp(etm, etmq, i);
> + if (ret)
> + return ret;
> + }
> +
> while (1) {
> if (!etm->heap.heap_cnt)
> goto out;
> --
> 2.28.0
>

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