aarch64: vp9itxfm: Skip empty slices in the first pass of idct_idct 16x16 and 32x32

This work is sponsored by, and copyright, Google.

Previously all subpartitions except the eob=1 (DC) case ran with
the same runtime:

vp9_inv_dct_dct_16x16_sub16_add_neon:   1373.2
vp9_inv_dct_dct_32x32_sub32_add_neon:   8089.0

By skipping individual 8x16 or 8x32 pixel slices in the first pass,
we reduce the runtime of these functions like this:

vp9_inv_dct_dct_16x16_sub1_add_neon:     235.3
vp9_inv_dct_dct_16x16_sub2_add_neon:    1036.7
vp9_inv_dct_dct_16x16_sub4_add_neon:    1036.7
vp9_inv_dct_dct_16x16_sub8_add_neon:    1036.7
vp9_inv_dct_dct_16x16_sub12_add_neon:   1372.1
vp9_inv_dct_dct_16x16_sub16_add_neon:   1372.1
vp9_inv_dct_dct_32x32_sub1_add_neon:     555.1
vp9_inv_dct_dct_32x32_sub2_add_neon:    5190.2
vp9_inv_dct_dct_32x32_sub4_add_neon:    5180.0
vp9_inv_dct_dct_32x32_sub8_add_neon:    5183.1
vp9_inv_dct_dct_32x32_sub12_add_neon:   6161.5
vp9_inv_dct_dct_32x32_sub16_add_neon:   6155.5
vp9_inv_dct_dct_32x32_sub20_add_neon:   7136.3
vp9_inv_dct_dct_32x32_sub24_add_neon:   7128.4
vp9_inv_dct_dct_32x32_sub28_add_neon:   8098.9
vp9_inv_dct_dct_32x32_sub32_add_neon:   8098.8

I.e. in general a very minor overhead for the full subpartition case due
to the additional cmps, but a significant speedup for the cases when we
only need to process a small part of the actual input data.

This is cherrypicked from libav commits
cad42fadcd and
a0c443a398.

Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
This commit is contained in:
Martin Storsjö 2017-01-10 00:15:16 +02:00 committed by Michael Niedermayer
parent 388f6e6715
commit 8b11a89c06
1 changed files with 56 additions and 5 deletions

View File

@ -588,6 +588,9 @@ endfunc
.macro store i, dst, inc
st1 {v\i\().8h}, [\dst], \inc
.endm
.macro movi_v i, size, imm
movi v\i\()\size, \imm
.endm
.macro load_clear i, src, inc
ld1 {v\i\().8h}, [\src]
st1 {v2.8h}, [\src], \inc
@ -596,9 +599,8 @@ endfunc
// Read a vertical 8x16 slice out of a 16x16 matrix, do a transform on it,
// transpose into a horizontal 16x8 slice and store.
// x0 = dst (temp buffer)
// x1 = unused
// x1 = slice offset
// x2 = src
// x3 = slice offset
// x9 = input stride
.macro itxfm16_1d_funcs txfm
function \txfm\()16_1d_8x16_pass1_neon
@ -616,14 +618,14 @@ function \txfm\()16_1d_8x16_pass1_neon
transpose_8x8H v24, v25, v26, v27, v28, v29, v30, v31, v2, v3
// Store the transposed 8x8 blocks horizontally.
cmp x3, #8
cmp x1, #8
b.eq 1f
.irp i, 16, 24, 17, 25, 18, 26, 19, 27, 20, 28, 21, 29, 22, 30, 23, 31
store \i, x0, #16
.endr
ret
1:
// Special case: For the last input column (x3 == 8),
// Special case: For the last input column (x1 == 8),
// which would be stored as the last row in the temp buffer,
// don't store the first 8x8 block, but keep it in registers
// for the first slice of the second pass (where it is the
@ -751,13 +753,36 @@ function ff_vp9_\txfm1\()_\txfm2\()_16x16_add_neon, export=1
.irp i, 0, 8
add x0, sp, #(\i*32)
.ifc \txfm1\()_\txfm2,idct_idct
.if \i == 8
cmp w3, #38
b.le 1f
.endif
.endif
mov x1, #\i
add x2, x6, #(\i*2)
mov x3, #\i
bl \txfm1\()16_1d_8x16_pass1_neon
.endr
.ifc \txfm1\()_\txfm2,iadst_idct
ld1 {v0.8h,v1.8h}, [x10]
.endif
.ifc \txfm1\()_\txfm2,idct_idct
b 3f
1:
// Set v24-v31 to zero, for the in-register passthrough of
// coefficients to pass 2. Since we only do two slices, this can
// only ever happen for the second slice. So we only need to store
// zeros to the temp buffer for the second half of the buffer.
// Move x0 to the second half, and use x9 == 32 as increment.
add x0, x0, #16
.irp i, 24, 25, 26, 27, 28, 29, 30, 31
movi_v \i, .16b, #0
st1 {v24.8h}, [x0], x9
.endr
3:
.endif
.irp i, 0, 8
add x0, x4, #(\i)
mov x1, x5
@ -1073,12 +1098,17 @@ function idct32_1d_8x32_pass2_neon
ret
endfunc
const min_eob_idct_idct_32, align=4
.short 0, 34, 135, 336
endconst
function ff_vp9_idct_idct_32x32_add_neon, export=1
cmp w3, #1
b.eq idct32x32_dc_add_neon
movrel x10, idct_coeffs
add x11, x10, #32
movrel x12, min_eob_idct_idct_32, 2
mov x15, x30
@ -1099,9 +1129,30 @@ function ff_vp9_idct_idct_32x32_add_neon, export=1
.irp i, 0, 8, 16, 24
add x0, sp, #(\i*64)
.if \i > 0
ldrh w1, [x12], #2
cmp w3, w1
mov x1, #(32 - \i)/4
b.le 1f
.endif
add x2, x6, #(\i*2)
bl idct32_1d_8x32_pass1_neon
.endr
b 3f
1:
// Write zeros to the temp buffer for pass 2
movi v16.8h, #0
movi v17.8h, #0
movi v18.8h, #0
movi v19.8h, #0
2:
subs x1, x1, #1
.rept 4
st1 {v16.8h-v19.8h}, [x0], #64
.endr
b.ne 2b
3:
.irp i, 0, 8, 16, 24
add x0, x4, #(\i)
mov x1, x5