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@sakamocchi.jp

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