Re: [PATCH 02/17] perf auxtrace: Allow number of queues to be specified

[Adrian Hunter]

On 29/04/24 18:21, James Clark wrote:
> Currently it's only possible to initialize with the default number of
> queues and then use auxtrace_queues__add_event() to grow the array. But
> that's problematic if you don't have a real event to pass into that
> function yet.
> 
> The queues hold a void *priv member to store custom state, and for
> Coresight we want to create decoders upfront before receiving data, so
> add a new function that allows pre-allocating queues. One reason to do
> this is because we might need to store metadata (HW_ID events) that
> effects other queues, but never actually receive auxtrace data on that
> queue.
> 
> Signed-off-by: James Clark <james.clark@xxxxxxx>

Acked-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>

> ---
>  tools/perf/util/auxtrace.c | 9 +++++++--
>  tools/perf/util/auxtrace.h | 1 +
>  2 files changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/perf/util/auxtrace.c b/tools/perf/util/auxtrace.c
> index 3684e6009b63..563b6c4fca31 100644
> --- a/tools/perf/util/auxtrace.c
> +++ b/tools/perf/util/auxtrace.c
> @@ -218,15 +218,20 @@ static struct auxtrace_queue *auxtrace_alloc_queue_array(unsigned int nr_queues)
>  	return queue_array;
>  }
>  
> -int auxtrace_queues__init(struct auxtrace_queues *queues)
> +int auxtrace_queues__init_nr(struct auxtrace_queues *queues, int nr_queues)
>  {
> -	queues->nr_queues = AUXTRACE_INIT_NR_QUEUES;
> +	queues->nr_queues = nr_queues;
>  	queues->queue_array = auxtrace_alloc_queue_array(queues->nr_queues);
>  	if (!queues->queue_array)
>  		return -ENOMEM;
>  	return 0;
>  }
>  
> +int auxtrace_queues__init(struct auxtrace_queues *queues)
> +{
> +	return auxtrace_queues__init_nr(queues, AUXTRACE_INIT_NR_QUEUES);
> +}
> +
>  static int auxtrace_queues__grow(struct auxtrace_queues *queues,
>  				 unsigned int new_nr_queues)
>  {
> diff --git a/tools/perf/util/auxtrace.h b/tools/perf/util/auxtrace.h
> index 55702215a82d..8a6ec9565835 100644
> --- a/tools/perf/util/auxtrace.h
> +++ b/tools/perf/util/auxtrace.h
> @@ -521,6 +521,7 @@ int auxtrace_mmap__read_snapshot(struct mmap *map,
>  				 struct perf_tool *tool, process_auxtrace_t fn,
>  				 size_t snapshot_size);
>  
> +int auxtrace_queues__init_nr(struct auxtrace_queues *queues, int nr_queues);
>  int auxtrace_queues__init(struct auxtrace_queues *queues);
>  int auxtrace_queues__add_event(struct auxtrace_queues *queues,
>  			       struct perf_session *session,