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ALSA: firewire-lib: cache maximum length of payload to reduce function calls
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> Signed-off-by: Takashi Iwai <tiwai@suse.de>
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parent
12ee4022f6
commit
f91c9d7610
2 changed files with 6 additions and 4 deletions
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@ -412,8 +412,7 @@ static inline int queue_out_packet(struct amdtp_stream *s,
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static inline int queue_in_packet(struct amdtp_stream *s)
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{
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return queue_packet(s, IN_PACKET_HEADER_SIZE,
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amdtp_stream_get_max_payload(s));
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return queue_packet(s, IN_PACKET_HEADER_SIZE, s->max_payload_length);
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}
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static int handle_out_packet(struct amdtp_stream *s,
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@ -713,12 +712,12 @@ static void in_stream_callback(struct fw_iso_context *context, u32 tstamp,
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cycle = decrement_cycle_count(cycle, packets);
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/* For buffer-over-run prevention. */
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max_payload_length = amdtp_stream_get_max_payload(s);
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max_payload_length = s->max_payload_length;
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for (i = 0; i < packets; i++) {
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cycle = increment_cycle_count(cycle, 1);
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/* The number of quadlets in this packet */
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/* The number of bytes in this packet */
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payload_length =
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(be32_to_cpu(headers[i]) >> ISO_DATA_LENGTH_SHIFT);
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if (payload_length > max_payload_length) {
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@ -751,6 +750,8 @@ static void amdtp_stream_first_callback(struct fw_iso_context *context,
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u32 cycle;
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unsigned int packets;
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s->max_payload_length = amdtp_stream_get_max_payload(s);
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/*
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* For in-stream, first packet has come.
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* For out-stream, prepared to transmit first packet
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@ -110,6 +110,7 @@ struct amdtp_stream {
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int (*handle_packet)(struct amdtp_stream *s,
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unsigned int payload_quadlets, unsigned int cycle,
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unsigned int index);
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unsigned int max_payload_length;
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/* For CIP headers. */
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unsigned int source_node_id_field;
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