Hello,
Benchmark of a loop doing './sbcenc big_buck_bunny_480p_stereo.au > /dev/null'
is listed below. The number of iterations was different for ARM and x86, so
absolute times for x86 and ARM can't be directly compared :)
=== ARM Cortex-A8 ===
before:
real 0m 12.51s
user 0m 11.00s
sys 0m 0.58s
after:
real 0m 11.50s
user 0m 10.04s
sys 0m 0.54s
=== Intel Core2 ===
before:
real 0m12.139s
user 0m11.817s
sys 0m0.300s
after:
real 0m10.074s
user 0m9.797s
sys 0m0.256s
===
Overall improvement is more visible on x86, but it is still good for ARM too.
Code size increases quite noticeably, but this seems to pay off anyway.
--
Best regards,
Siarhei Siamashka
>From 91d800ecc5f48692588ff908ca212d70eef5d0d3 Mon Sep 17 00:00:00 2001
From: Siarhei Siamashka <siarhei.siamashka@xxxxxxxxx>
Date: Wed, 21 Jan 2009 21:08:34 +0200
Subject: [PATCH] Use of -funroll-loops option to improve SBC encoder performance
Added the use of -funroll-loops gcc option for SBC. Also in
order to gain better effect, 'sbc_pack_frame' function
body moved to an inline function, which gets instantiated
for 4 different subbands/channels combinations. So that
'frame_subbands' and 'frame_channels' arguments become compile
time constants and can be better optimized by the compiler.
---
sbc/Makefile.am | 3 ++-
sbc/sbc.c | 49 +++++++++++++++++++++++++++++++++----------------
sbc/sbc_primitives.h | 6 ++++++
3 files changed, 41 insertions(+), 17 deletions(-)
diff --git a/sbc/Makefile.am b/sbc/Makefile.am
index d4ad194..3feb178 100644
--- a/sbc/Makefile.am
+++ b/sbc/Makefile.am
@@ -12,7 +12,8 @@ libsbc_la_SOURCES = sbc.h sbc.c sbc_math.h sbc_tables.h \
sbc_primitives.h sbc_primitives_mmx.h sbc_primitives_neon.h \
sbc_primitives.c sbc_primitives_mmx.c sbc_primitives_neon.c
-libsbc_la_CFLAGS = -finline-functions -funswitch-loops -fgcse-after-reload
+libsbc_la_CFLAGS = -finline-functions -funswitch-loops -fgcse-after-reload \
+ -funroll-loops
noinst_PROGRAMS = sbcinfo sbcdec sbcenc $(sndfile_programs)
diff --git a/sbc/sbc.c b/sbc/sbc.c
index 827b731..190ac17 100644
--- a/sbc/sbc.c
+++ b/sbc/sbc.c
@@ -731,7 +731,9 @@ static int sbc_analyze_audio(struct sbc_encoder_state *state,
* -99 not implemented
*/
-static int sbc_pack_frame(uint8_t *data, struct sbc_frame *frame, size_t len)
+static SBC_ALWAYS_INLINE int sbc_pack_frame_internal(
+ uint8_t *data, struct sbc_frame *frame, size_t len,
+ int frame_subbands, int frame_channels)
{
/* Bitstream writer starts from the fourth byte */
uint8_t *data_ptr = data + 4;
@@ -761,7 +763,7 @@ static int sbc_pack_frame(uint8_t *data, struct sbc_frame *frame, size_t len)
data[1] |= (frame->allocation & 0x01) << 1;
- switch (frame->subbands) {
+ switch (frame_subbands) {
case 4:
/* Nothing to do */
break;
@@ -776,11 +778,11 @@ static int sbc_pack_frame(uint8_t *data, struct sbc_frame *frame, size_t len)
data[2] = frame->bitpool;
if ((frame->mode == MONO || frame->mode == DUAL_CHANNEL) &&
- frame->bitpool > frame->subbands << 4)
+ frame->bitpool > frame_subbands << 4)
return -5;
if ((frame->mode == STEREO || frame->mode == JOINT_STEREO) &&
- frame->bitpool > frame->subbands << 5)
+ frame->bitpool > frame_subbands << 5)
return -5;
/* Can't fill in crc yet */
@@ -789,8 +791,8 @@ static int sbc_pack_frame(uint8_t *data, struct sbc_frame *frame, size_t len)
crc_header[1] = data[2];
crc_pos = 16;
- for (ch = 0; ch < frame->channels; ch++) {
- for (sb = 0; sb < frame->subbands; sb++) {
+ for (ch = 0; ch < frame_channels; ch++) {
+ for (sb = 0; sb < frame_subbands; sb++) {
frame->scale_factor[ch][sb] = 0;
scalefactor[ch][sb] = 2 << SCALE_OUT_BITS;
for (blk = 0; blk < frame->blocks; blk++) {
@@ -812,7 +814,7 @@ static int sbc_pack_frame(uint8_t *data, struct sbc_frame *frame, size_t len)
uint8_t joint = 0;
frame->joint = 0;
- for (sb = 0; sb < frame->subbands - 1; sb++) {
+ for (sb = 0; sb < frame_subbands - 1; sb++) {
scale_factor_j[0] = 0;
scalefactor_j[0] = 2 << SCALE_OUT_BITS;
scale_factor_j[1] = 0;
@@ -844,7 +846,7 @@ static int sbc_pack_frame(uint8_t *data, struct sbc_frame *frame, size_t len)
(scale_factor_j[0] +
scale_factor_j[1])) {
/* use joint stereo for this subband */
- joint |= 1 << (frame->subbands - 1 - sb);
+ joint |= 1 << (frame_subbands - 1 - sb);
frame->joint |= 1 << sb;
frame->scale_factor[0][sb] = scale_factor_j[0];
frame->scale_factor[1][sb] = scale_factor_j[1];
@@ -858,13 +860,13 @@ static int sbc_pack_frame(uint8_t *data, struct sbc_frame *frame, size_t len)
}
PUT_BITS(data_ptr, bits_cache, bits_count,
- joint, frame->subbands);
+ joint, frame_subbands);
crc_header[crc_pos >> 3] = joint;
- crc_pos += frame->subbands;
+ crc_pos += frame_subbands;
}
- for (ch = 0; ch < frame->channels; ch++) {
- for (sb = 0; sb < frame->subbands; sb++) {
+ for (ch = 0; ch < frame_channels; ch++) {
+ for (sb = 0; sb < frame_subbands; sb++) {
PUT_BITS(data_ptr, bits_cache, bits_count,
frame->scale_factor[ch][sb] & 0x0F, 4);
crc_header[crc_pos >> 3] <<= 4;
@@ -881,8 +883,8 @@ static int sbc_pack_frame(uint8_t *data, struct sbc_frame *frame, size_t len)
sbc_calculate_bits(frame, bits);
- for (ch = 0; ch < frame->channels; ch++) {
- for (sb = 0; sb < frame->subbands; sb++) {
+ for (ch = 0; ch < frame_channels; ch++) {
+ for (sb = 0; sb < frame_subbands; sb++) {
levels[ch][sb] = ((1 << bits[ch][sb]) - 1) <<
(32 - (frame->scale_factor[ch][sb] +
SCALE_OUT_BITS + 2));
@@ -893,8 +895,8 @@ static int sbc_pack_frame(uint8_t *data, struct sbc_frame *frame, size_t len)
}
for (blk = 0; blk < frame->blocks; blk++) {
- for (ch = 0; ch < frame->channels; ch++) {
- for (sb = 0; sb < frame->subbands; sb++) {
+ for (ch = 0; ch < frame_channels; ch++) {
+ for (sb = 0; sb < frame_subbands; sb++) {
if (bits[ch][sb] == 0)
continue;
@@ -914,6 +916,21 @@ static int sbc_pack_frame(uint8_t *data, struct sbc_frame *frame, size_t len)
return data_ptr - data;
}
+static int sbc_pack_frame(uint8_t *data, struct sbc_frame *frame, size_t len)
+{
+ if (frame->subbands == 4) {
+ if (frame->channels == 1)
+ return sbc_pack_frame_internal(data, frame, len, 4, 1);
+ else
+ return sbc_pack_frame_internal(data, frame, len, 4, 2);
+ } else {
+ if (frame->channels == 1)
+ return sbc_pack_frame_internal(data, frame, len, 8, 1);
+ else
+ return sbc_pack_frame_internal(data, frame, len, 8, 2);
+ }
+}
+
static void sbc_encoder_init(struct sbc_encoder_state *state,
const struct sbc_frame *frame)
{
diff --git a/sbc/sbc_primitives.h b/sbc/sbc_primitives.h
index 91b72ee..a418ed8 100644
--- a/sbc/sbc_primitives.h
+++ b/sbc/sbc_primitives.h
@@ -28,6 +28,12 @@
#define SCALE_OUT_BITS 15
+#ifdef __GNUC__
+#define SBC_ALWAYS_INLINE __attribute__((always_inline))
+#else
+#define SBC_ALWAYS_INLINE inline
+#endif
+
struct sbc_encoder_state {
int subbands;
int position[2];
--
1.5.6.5
