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| author | Takashi Sakamoto <o-takashi@sakamocchi.jp> | 2017-04-11 14:33:18 +0300 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2017-04-12 16:34:21 +0300 |
| commit | f91c9d7610a2fe306273a83e2fd5351bceb85d28 (patch) | |
| tree | 83e477ea0a5ccdaa6f6e57e5ccbd83882c7a2d45 /sound/firewire | |
| parent | 12ee4022f67f8854061b46e5c0a7ad6258ab66c2 (diff) | |
| download | linux-f91c9d7610a2fe306273a83e2fd5351bceb85d28.tar.xz | |
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>
Diffstat (limited to 'sound/firewire')
| -rw-r--r-- | sound/firewire/amdtp-stream.c | 9 | ||||
| -rw-r--r-- | 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 f6af8e64c2cd..9e6f54f8c45d 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 2bd4de4c7bb7..7e8831722821 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; |