On Tue, 11 Apr 2017 13:33:18 +0200,
Takashi Sakamoto wrote:
>
> During packet streaming, maximum length of payload for isochronous packet
> is invariable, therefore no need to recalculate. Current ALSA IEC 61883-1/6
> engine calls a function to calculate it 8,000 or more times per second
> for incoming packet processing.
>
> This commit adds a member to have maximum length of payload into 'struct
> amdtp_stream', to reduces the function calls. At first callback from
> isochronous context, the length is calculated and stored for later
> processing.
>
> Signed-off-by: Takashi Sakamoto <o-takashi@xxxxxxxxxxxxx>
Applied, thanks.
Takashi
> ---
> sound/firewire/amdtp-stream.c | 9 +++++----
> sound/firewire/amdtp-stream.h | 1 +
> 2 files changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/sound/firewire/amdtp-stream.c b/sound/firewire/amdtp-stream.c
> index f6af8e6..9e6f54f 100644
> --- a/sound/firewire/amdtp-stream.c
> +++ b/sound/firewire/amdtp-stream.c
> @@ -412,8 +412,7 @@ static inline int queue_out_packet(struct amdtp_stream *s,
>
> static inline int queue_in_packet(struct amdtp_stream *s)
> {
> - return queue_packet(s, IN_PACKET_HEADER_SIZE,
> - amdtp_stream_get_max_payload(s));
> + return queue_packet(s, IN_PACKET_HEADER_SIZE, s->max_payload_length);
> }
>
> static int handle_out_packet(struct amdtp_stream *s,
> @@ -713,12 +712,12 @@ static void in_stream_callback(struct fw_iso_context *context, u32 tstamp,
> cycle = decrement_cycle_count(cycle, packets);
>
> /* For buffer-over-run prevention. */
> - max_payload_length = amdtp_stream_get_max_payload(s);
> + max_payload_length = s->max_payload_length;
>
> for (i = 0; i < packets; i++) {
> cycle = increment_cycle_count(cycle, 1);
>
> - /* The number of quadlets in this packet */
> + /* The number of bytes in this packet */
> payload_length =
> (be32_to_cpu(headers[i]) >> ISO_DATA_LENGTH_SHIFT);
> if (payload_length > max_payload_length) {
> @@ -751,6 +750,8 @@ static void amdtp_stream_first_callback(struct fw_iso_context *context,
> u32 cycle;
> unsigned int packets;
>
> + s->max_payload_length = amdtp_stream_get_max_payload(s);
> +
> /*
> * For in-stream, first packet has come.
> * For out-stream, prepared to transmit first packet
> diff --git a/sound/firewire/amdtp-stream.h b/sound/firewire/amdtp-stream.h
> index 2bd4de4..7e88317 100644
> --- a/sound/firewire/amdtp-stream.h
> +++ b/sound/firewire/amdtp-stream.h
> @@ -110,6 +110,7 @@ struct amdtp_stream {
> int (*handle_packet)(struct amdtp_stream *s,
> unsigned int payload_quadlets, unsigned int cycle,
> unsigned int index);
> + unsigned int max_payload_length;
>
> /* For CIP headers. */
> unsigned int source_node_id_field;
> --
> 2.9.3
>
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