"+ * The original enqueue order of the source queue is maintained when
buffers are
+ * enqueued to their destination queue(s) before another schedule call"

Is this assuming that the order will be restored always at the next
enqueue? I think there should be an option to explicitly indicate if the
next enqueue is supposed to restore the order or not, especially when
packets move from queue to queue. Ordered queues are costly compared with
the ordinary ones.

Alex

On 31 October 2014 14:25, Petri Savolainen <petri.savolai...@linaro.org>
wrote:

> Improved atomic and ordered synchronisation definitions. Added
> order skip function prototype.
>
> Signed-off-by: Petri Savolainen <petri.savolai...@linaro.org>
>
> ---
> This is the ordered queue definition (in patch format) promised
> in the call yesterday.
> ---
>  platform/linux-generic/include/api/odp_queue.h    | 31 +++++++++++++++-
>  platform/linux-generic/include/api/odp_schedule.h | 45
> ++++++++++++++++++-----
>  2 files changed, 64 insertions(+), 12 deletions(-)
>
> diff --git a/platform/linux-generic/include/api/odp_queue.h
> b/platform/linux-generic/include/api/odp_queue.h
> index b8ac4bb..c0c3969 100644
> --- a/platform/linux-generic/include/api/odp_queue.h
> +++ b/platform/linux-generic/include/api/odp_queue.h
> @@ -78,8 +78,35 @@ typedef int odp_schedule_prio_t;
>  typedef int odp_schedule_sync_t;
>
>  #define ODP_SCHED_SYNC_NONE     0  /**< Queue not synchronised */
> -#define ODP_SCHED_SYNC_ATOMIC   1  /**< Atomic queue */
> -#define ODP_SCHED_SYNC_ORDERED  2  /**< Ordered queue */
> +
> +/**
> + * Atomic queue synchronisation
> + *
> + * The scheduler gives buffers from a queue to a single core at a time.
> This
> + * serialises processing of the buffers from the source queue and helps
> user to
> + * avoid SW locking. Another schedule call will implicitely release the
> atomic
> + * synchronisation of the source queue and free the scheduler to give
> buffers
> + * from the queue to other cores.
> + *
> + * User can hint the scheduler to release the atomic synchronisation
> early with
> + * odp_schedule_release_atomic().
> + */
> +#define ODP_SCHED_SYNC_ATOMIC   1
> +
> +/**
> + * Ordered queue synchronisation
> + *
> + * The scheduler may give out buffers to multiple cores for parallel
> processing.
> + * The original enqueue order of the source queue is maintained when
> buffers are
> + * enqueued to their destination queue(s) before another schedule call.
> Buffers
> + * from the same ordered (source) queue appear in their original order
> when
> + * dequeued from a destination queue. The destination queue type
> (POLL/SCHED) or
> + * synchronisation (NONE/ATOMIC/ORDERED) is not limited.
> + *
> + * User can command the scheduler to skip ordering of a buffer with
> + * odp_schedule_skip_order().
> + */
> +#define ODP_SCHED_SYNC_ORDERED  2
>
>  /** Default queue synchronisation */
>  #define ODP_SCHED_SYNC_DEFAULT  ODP_SCHED_SYNC_ATOMIC
> diff --git a/platform/linux-generic/include/api/odp_schedule.h
> b/platform/linux-generic/include/api/odp_schedule.h
> index 91fec10..2a1a642 100644
> --- a/platform/linux-generic/include/api/odp_schedule.h
> +++ b/platform/linux-generic/include/api/odp_schedule.h
> @@ -52,8 +52,8 @@ uint64_t odp_schedule_wait_time(uint64_t ns);
>   * for a buffer according to the wait parameter setting. Returns
>   * ODP_BUFFER_INVALID if reaches end of the wait period.
>   *
> - * @param from    Output parameter for the source queue (where the buffer
> was
> - *                dequeued from). Ignored if NULL.
> + * @param src     The source queue (output). Indicates from which queue
> the
> + *                buffer was dequeued. Ignored if NULL.
>   * @param wait    Minimum time to wait for a buffer. Waits infinitely, if
> set to
>   *                ODP_SCHED_WAIT. Does not wait, if set to
> ODP_SCHED_NO_WAIT.
>   *                Use odp_schedule_wait_time() to convert time to other
> wait
> @@ -61,7 +61,7 @@ uint64_t odp_schedule_wait_time(uint64_t ns);
>   *
>   * @return Next highest priority buffer, or ODP_BUFFER_INVALID
>   */
> -odp_buffer_t odp_schedule(odp_queue_t *from, uint64_t wait);
> +odp_buffer_t odp_schedule(odp_queue_t *src, uint64_t wait);
>
>  /**
>   * Schedule one buffer
> @@ -76,8 +76,8 @@ odp_buffer_t odp_schedule(odp_queue_t *from, uint64_t
> wait);
>   *
>   * User can exit the schedule loop without first calling
> odp_schedule_pause().
>   *
> - * @param from    Output parameter for the source queue (where the buffer
> was
> - *                dequeued from). Ignored if NULL.
> + * @param src     The source queue (output). Indicates from which queue
> the
> + *                buffer was dequeued. Ignored if NULL.
>   * @param wait    Minimum time to wait for a buffer. Waits infinitely, if
> set to
>   *                ODP_SCHED_WAIT. Does not wait, if set to
> ODP_SCHED_NO_WAIT.
>   *                Use odp_schedule_wait_time() to convert time to other
> wait
> @@ -85,7 +85,7 @@ odp_buffer_t odp_schedule(odp_queue_t *from, uint64_t
> wait);
>   *
>   * @return Next highest priority buffer, or ODP_BUFFER_INVALID
>   */
> -odp_buffer_t odp_schedule_one(odp_queue_t *from, uint64_t wait);
> +odp_buffer_t odp_schedule_one(odp_queue_t *src, uint64_t wait);
>
>
>  /**
> @@ -93,8 +93,8 @@ odp_buffer_t odp_schedule_one(odp_queue_t *from,
> uint64_t wait);
>   *
>   * Like odp_schedule(), but returns multiple buffers from a queue.
>   *
> - * @param from    Output parameter for the source queue (where the buffer
> was
> - *                dequeued from). Ignored if NULL.
> + * @param src     The source queue (output). Indicates from which queue
> the
> + *                buffer was dequeued. Ignored if NULL.
>   * @param wait    Minimum time to wait for a buffer. Waits infinitely, if
> set to
>   *                ODP_SCHED_WAIT. Does not wait, if set to
> ODP_SCHED_NO_WAIT.
>   *                Use odp_schedule_wait_time() to convert time to other
> wait
> @@ -104,7 +104,7 @@ odp_buffer_t odp_schedule_one(odp_queue_t *from,
> uint64_t wait);
>   *
>   * @return Number of buffers outputed (0 ... num)
>   */
> -int odp_schedule_multi(odp_queue_t *from, uint64_t wait, odp_buffer_t
> out_buf[],
> +int odp_schedule_multi(odp_queue_t *src, uint64_t wait, odp_buffer_t
> out_buf[],
>                        unsigned int num);
>
>  /**
> @@ -129,11 +129,36 @@ void odp_schedule_pause(void);
>  void odp_schedule_resume(void);
>
>  /**
> - * Release currently hold atomic context
> + * Release the current atomic context
> + *
> + * This calls is valid only when the source queue has ATOMIC
> synchronisation. It
> + * hints the scheduler that the user has completed processing the critical
> + * section that needs atomic synchronisation. After the call, the
> scheduler is
> + * allowed to give next buffer from the same queue to another core.
> + *
> + * Usage of the call may increase parallelism and thus system
> performance, but
> + * carefulness is needed when splitting processing into critical vs.
> + * non-critical sections.
>   */
>  void odp_schedule_release_atomic(void);
>
>  /**
> + * Skip ordering of the buffer
> + *
> + * This calls is valid only when source queue has ORDERED
> synchronisation. It
> + * commands the scheduler to skip ordering of the buffer. Scheduler
> maintains
> + * ordering between two queues: source and destination. The dest parameter
> + * identifies the destination queue of that pair. After the call,
> ordering is
> + * not maintained for the buffer anymore but user still owns the buffer.
> User
> + * can e.g. store it, free it or enqueue it (to the same or another
> queue).
> + *
> + * @param dest    Destination queue
> + * @param buf     Buffer
> + */
> +void odp_schedule_skip_order(odp_queue_t dest, odp_buffer_t buf);
> +
> +
> +/**
>   * Number of scheduling priorities
>   *
>   * @return Number of scheduling priorities
> --
> 2.1.1
>
>
> _______________________________________________
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> lng-odp@lists.linaro.org
> http://lists.linaro.org/mailman/listinfo/lng-odp
>
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