[PATCH v1 03/13] graph: add macro to walk on graph circular buffer

[Jerin Jacob]

On Thu, Nov 17, 2022 at 10:40 AM Zhirun Yan <zhirun.yan at intel.com> wrote:
>
> It is common to walk on graph circular buffer and use macro to make
> it reusable for other worker models.
>
> Signed-off-by: Haiyue Wang <haiyue.wang at intel.com>
> Signed-off-by: Cunming Liang <cunming.liang at intel.com>
> Signed-off-by: Zhirun Yan <zhirun.yan at intel.com>
> ---
>  lib/graph/rte_graph_model_rtc.h     | 23 ++---------------------
>  lib/graph/rte_graph_worker_common.h | 23 +++++++++++++++++++++++
>  2 files changed, 25 insertions(+), 21 deletions(-)

> +/**
> + * Macro to walk on the source node(s) ((cir_start - head) -> cir_start)
> + * and then on the pending streams
> + * (cir_start -> (cir_start + mask) -> cir_start)
> + * in a circular buffer fashion.
> + *
> + *     +-----+ <= cir_start - head [number of source nodes]
> + *     |     |
> + *     | ... | <= source nodes
> + *     |     |
> + *     +-----+ <= cir_start [head = 0] [tail = 0]
> + *     |     |
> + *     | ... | <= pending streams
> + *     |     |
> + *     +-----+ <= cir_start + mask
> + */
> +#define rte_graph_walk_node(graph, head, node)                                         \
> +       for ((node) = RTE_PTR_ADD((graph), (graph)->cir_start[(int32_t)(head)]);        \
> +            likely((head) != (graph)->tail);                                           \
> +            (head)++,                                                                  \
> +            (node) = RTE_PTR_ADD((graph), (graph)->cir_start[(int32_t)(head)]),        \

This is an additional assignment compare to original while() based
version. Right?
No need to generalize with performance impact.


> +            (head) = likely((int32_t)(head) > 0) ? (head) & (graph)->cir_mask : (head))
> +
>  /**
>   * @internal
>   *
> --
> 2.25.1
>