Re: [x265] [PATCH] asm: intrapred dc8 sse2 high bit

[dave]

On 02/26/2015 02:43 PM, Steve Borho wrote:
On 02/26, dave wrote:
On 02/25/2015 05:59 AM, chen wrote:
At 2015-02-25 08:16:44,dtyx...@gmail.com wrote:
# HG changeset patch
# User David T Yuen <dtyx...@gmail.com>
# Date 1424823199 28800
# Node ID bd1d713da87bb1e3022c80f462398bd78a95ce48
# Parent  644d27ca0b197455393171ba705b1190f3d9b420
asm: intrapred dc8 sse2 high bit
This replaces c code for systems using ssse3 to sse2 processors
The code is backported from intrapred dc8 sse4 high bit

./test/TestBench --testbench intrapred | grep 8x8
intra_dc_8x8[f=0]       1.62x    443.94          717.32
intra_dc_8x8[f=1]       1.59x    729.98          1157.66

diff -r 644d27ca0b19 -r bd1d713da87b source/common/x86/asm-primitives.cpp
--- a/source/common/x86/asm-primitives.cpp      Tue Feb 24 14:47:01 2015 -0800
+++ b/source/common/x86/asm-primitives.cpp      Tue Feb 24 16:13:19 2015 -0800
@@ -864,6 +864,7 @@
         ALL_LUMA_TU_S(transpose, transpose, sse2);

         p.cu[BLOCK_4x4].intra_pred[DC_IDX] = x265_intra_pred_dc4_sse2;
+        p.cu[BLOCK_8x8].intra_pred[DC_IDX] = x265_intra_pred_dc8_sse2;

         p.cu[BLOCK_4x4].sse_ss = x265_pixel_ssd_ss_4x4_mmx2;
         ALL_LUMA_CU(sse_ss, pixel_ssd_ss, sse2);
diff -r 644d27ca0b19 -r bd1d713da87b source/common/x86/intrapred16.asm
--- a/source/common/x86/intrapred16.asm Tue Feb 24 14:47:01 2015 -0800
+++ b/source/common/x86/intrapred16.asm Tue Feb 24 16:13:19 2015 -0800
@@ -86,6 +86,7 @@
cextern pw_8
cextern pw_16
cextern pw_1023
+cextern pd_2
cextern pd_16
cextern pd_32
cextern pw_4096
@@ -166,6 +167,89 @@
;-----------------------------------------------------------------------------------
; void intra_pred_dc(pixel* dst, intptr_t dstStride, pixel* above, int, int 
filter)
;-----------------------------------------------------------------------------------
+INIT_XMM sse2
+cglobal intra_pred_dc8, 5, 8, 2
+    add             r2,            2
+    add             r1,            r1
+    movu            m0,            [r2 + 32]
+    movu            m1,            [r2]
+
+    paddw           m0,            m1
+    movhlps         m1,            m0
+    paddw           m0,            m1
+    pshufd          m1,            m0, 1
+    paddw           m0,            m1
+    pmaddwd         m0,            [pw_1]
+
+    paddw           m0,            [pw_8]
+    psraw           m0,            4              ; sum = sum / 16
+    pshuflw         m0,            m0, 0
+    pshufd          m0,            m0, 0          ; m0 = word [dc_val ...]
+
+    test            r4d,           r4d
+
+    ; store DC 8x8
+    lea             r6,            [r1 + r1 * 2]
+    lea             r5,            [r6 + r1 * 2]
+    lea             r7,            [r6 + r1 * 4]
+    movu            [r0],          m0
+    movu            [r0 + r1],     m0
+    movu            [r0 + r1 * 2], m0
+    movu            [r0 + r6],     m0
+    movu            [r0 + r1 * 4], m0
+    movu            [r0 + r5],     m0
+    movu            [r0 + r6 * 2], m0
+    movu            [r0 + r7],     m0
+
+    ; Do DC Filter
+    jz              .end
+    mova            m1,            [pd_2]
+    pmullw          m1,            m0
[x x x x] * [0 2 0 2] = [0 dc*2 0 dc*2], am I right?
Why not PSLL?
For some reason using psllw in place of pmullw hurts performance of
unfiltered in 8 and 10 bit far more than you would expect for such a
small change.  8 bit speed is cut by more than half

./test/TestBench --testbench intrapred | grep 8x8

intra_dc_8x8[f=0]    1.84x      492.58        906.63
intra_dc_8x8[f=1]    2.38x      537.68        1280.02

  and 10 bit is barely faster than c code.

./test/TestBench --testbench intrapred | grep 8x8
intra_dc_8x8[f=0]    1.06x      677.54        719.80
intra_dc_8x8[f=1]    1.60x      725.05        1157.54

I will resubmit with other adjustments
You may find this useful, if you have not seen it before:

https://software.intel.com/en-us/articles/intel-architecture-code-analyzer

Thanks!  I am running an athlon cpu but it looks like amd has a similar 
tool.

http://developer.amd.com/tools-and-sdks/opencl-zone/codexl/

It will be interesting to see how each one views the same code.
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