[FFmpeg-devel] [PATCH v1 3/3] swscale/la: Add output_lasx.c file.

[Shiyou Yin]

> 2022年9月9日 21:11，Andreas Rheinhardt <andreas.rheinhardt at outlook.com> 写道：
> 
> Shiyou Yin:
>> 
>> 
>>> 2022年9月6日 16:12，Shiyou Yin <yinshiyou-hf at loongson.cn> 写道：
>>> 
>>>> 
>>>> 2022年8月29日 20:30，Andreas Rheinhardt <andreas.rheinhardt at outlook.com <mailto:andreas.rheinhardt at outlook.com>> 写道：
>>>> 
>>>> Hao Chen:
>>>>> ffmpeg -i ~/media/1_h264_1080p_30fps_3Mbps.mp4 -f rawvideo -s 640x480 -pix_fmt
>>>>> rgb24 -y /dev/null -an
>>>>> before: 150fps
>>>>> after: 183fps
>>>>> 
>>>>> Signed-off-by: Hao Chen <chenhao at loongson.cn>
>>>>> ---
>>>>> libswscale/loongarch/Makefile | 3 +-
>>>>> libswscale/loongarch/output_lasx.c | 1982 +++++++++++++++++
>>>>> libswscale/loongarch/swscale_init_loongarch.c | 3 +
>>>>> libswscale/loongarch/swscale_loongarch.h | 6 +
>>>>> 4 files changed, 1993 insertions(+), 1 deletion(-)
>>>>> create mode 100644 libswscale/loongarch/output_lasx.c
>>>>> 
>> 
>>>>> +static void
>>>>> +yuv2rgb_2_template_lasx(SwsContext *c, const int16_t *buf[2],
>>>>> + const int16_t *ubuf[2], const int16_t *vbuf[2],
>>>>> + const int16_t *abuf[2], uint8_t *dest, int dstW,
>>>>> + int yalpha, int uvalpha, int y,
>>>>> + enum AVPixelFormat target, int hasAlpha)
>>>>> +{
>>>>> + const int16_t *buf0 = buf[0], *buf1 = buf[1],
>>>>> + *ubuf0 = ubuf[0], *ubuf1 = ubuf[1],
>>>>> + *vbuf0 = vbuf[0], *vbuf1 = vbuf[1];
>>>>> + int yalpha1 = 4096 - yalpha;
>>>>> + int uvalpha1 = 4096 - uvalpha;
>>>>> + int i, count = 0;
>>>>> + int len = dstW - 15;
>>>>> + int len_count = (dstW + 1) >> 1;
>>>>> + const void *r, *g, *b;
>>>>> + int head = YUVRGB_TABLE_HEADROOM;
>>>>> + __m256i v_yalpha1 = __lasx_xvreplgr2vr_w(yalpha1);
>>>>> + __m256i v_uvalpha1 = __lasx_xvreplgr2vr_w(uvalpha1);
>>>>> + __m256i v_yalpha = __lasx_xvreplgr2vr_w(yalpha);
>>>>> + __m256i v_uvalpha = __lasx_xvreplgr2vr_w(uvalpha);
>>>>> + __m256i headroom = __lasx_xvreplgr2vr_w(head);
>>>>> +
>>>>> + for (i = 0; i < len; i += 16) {
>>>>> + int Y1, Y2, U, V;
>>>>> + int i_dex = i << 1;
>>>>> + int c_dex = count << 1;
>>>>> + __m256i y0_h, y0_l, y0, u0, v0;
>>>>> + __m256i y1_h, y1_l, y1, u1, v1;
>>>>> + __m256i y_l, y_h, u, v;
>>>>> +
>>>>> + DUP4_ARG2(__lasx_xvldx, buf0, i_dex, ubuf0, c_dex, vbuf0, c_dex,
>>>>> + buf1, i_dex, y0, u0, v0, y1);
>>>>> + DUP2_ARG2(__lasx_xvldx, ubuf1, c_dex, vbuf1, c_dex, u1, v1);
>>>>> + DUP2_ARG2(__lasx_xvsllwil_w_h, y0, 0, y1, 0, y0_l, y1_l);
>>>>> + DUP2_ARG1(__lasx_xvexth_w_h, y0, y1, y0_h, y1_h);
>>>>> + DUP4_ARG1(__lasx_vext2xv_w_h, u0, u1, v0, v1, u0, u1, v0, v1);
>>>>> + y0_l = __lasx_xvmul_w(y0_l, v_yalpha1);
>>>>> + y0_h = __lasx_xvmul_w(y0_h, v_yalpha1);
>>>>> + u0 = __lasx_xvmul_w(u0, v_uvalpha1);
>>>>> + v0 = __lasx_xvmul_w(v0, v_uvalpha1);
>>>>> + y_l = __lasx_xvmadd_w(y0_l, v_yalpha, y1_l);
>>>>> + y_h = __lasx_xvmadd_w(y0_h, v_yalpha, y1_h);
>>>>> + u = __lasx_xvmadd_w(u0, v_uvalpha, u1);
>>>>> + v = __lasx_xvmadd_w(v0, v_uvalpha, v1);
>>>>> + y_l = __lasx_xvsrai_w(y_l, 19);
>>>>> + y_h = __lasx_xvsrai_w(y_h, 19);
>>>>> + u = __lasx_xvsrai_w(u, 19);
>>>>> + v = __lasx_xvsrai_w(v, 19);
>>>>> + u = __lasx_xvadd_w(u, headroom);
>>>>> + v = __lasx_xvadd_w(v, headroom);
>>>>> + WRITE_YUV2RGB(y_l, y_l, u, v, 0, 1, 0, 0);
>>>>> + WRITE_YUV2RGB(y_l, y_l, u, v, 2, 3, 1, 1);
>>>>> + WRITE_YUV2RGB(y_h, y_h, u, v, 0, 1, 2, 2);
>>>>> + WRITE_YUV2RGB(y_h, y_h, u, v, 2, 3, 3, 3);
>>>>> + WRITE_YUV2RGB(y_l, y_l, u, v, 4, 5, 4, 4);
>>>>> + WRITE_YUV2RGB(y_l, y_l, u, v, 6, 7, 5, 5);
>>>>> + WRITE_YUV2RGB(y_h, y_h, u, v, 4, 5, 6, 6);
>>>>> + WRITE_YUV2RGB(y_h, y_h, u, v, 6, 7, 7, 7);
>>>>> + }
>>>>> + if (dstW - i >= 8) {
>>>>> + int Y1, Y2, U, V;
>>>>> + int i_dex = i << 1;
>>>>> + __m256i y0_l, y0, u0, v0;
>>>>> + __m256i y1_l, y1, u1, v1;
>>>>> + __m256i y_l, u, v;
>>>>> +
>>>>> + y0 = __lasx_xvldx(buf0, i_dex);
>>>> 
>>>> 1. Not long ago, I tried to constify the src pointer of several asm
>>>> functions and noticed that they produced new warnings for loongarch
>>>> (according to patchwork:
>>>> https://patchwork.ffmpeg.org/project/ffmpeg/patch/DB6PR0101MB2214178D3E6B8DCA5B86F8198F9A9@DB6PR0101MB2214.eurprd01.prod.exchangelabs.com/),
>>>> even though I was sure that the code is const-correct. After finding
>>>> (via https://github.com/opencv/opencv/pull/21833) a toolchain
>>>> (https://gitee.com/wenux/cross-compiler-la-on-x86) that can build the
>>>> lasx and lsx code (upstream GCC seems to be lacking lsx and lasx support
>>>> at the moment; at least, my self-compiled loongarch-GCC did not support
>>>> lsx and lasx) the issue was clear: lsxintrin.h and lasxintrin.h do not
>>>> use const at all, even for functions that only read data (I presume the
>>>> vl in __lsx_vldx stands for "vector load"?).
>>>> So I sent another iteration
>>>> https://ffmpeg.org/pipermail/ffmpeg-devel/2022-August/299562.html of
>>>> that patchset that now added wrappers for __lsx_vldx() and
>>>> __lasx_xvldx() and cc'ed you and some other developers from loongson to
>>>> alert you of the issue in the hope that you fix the headers, so that my
>>>> wrappers wouldn't need to be applied. That didn't work, as my mails
>>>> could not be delivered to you. So I applied the patchset.
>>>> 2. You use __lasx_xvldx() to read from a const int16_t. This will give
>>>> new warnings unless the above issue has been fixed. Has it?
>>>> 3. I don't know whether it has, as patchwork's fate tests don't work for
>>>> a few days already. Given that the mails I receive from patchwork when
>>>> it doesn't like a commit message arrive from "Patchwork
>>>> <yinshiyou-hf at loongson.cn>" I presume that loongson is now somehow
>>>> running patchwork, so you should be able to inform the right people to
>>>> fix it.
>>>> 4. If you fixed the const-issue, can you please make an updated
>>>> toolchain with lsx and lasx support enabled available to us?
>>>> 
>>>> - Andreas
>>>> 
>>> 
>>> Hi Andreas,
>>> 
>>> Sorry for the late reply.
>>> This issue will be fixed by using const for v1 of __lsx_vldx, and I will update toolchain of LoongArch patchwork runner ASAP.
>>> Thank you very much for analyzing this problem and giving suggestion. 
>>> 
>>> Thanks,
>>> Shiyou
>> 
>> Hi Andreas,
>> Has updated patchwork runner environment, you can revert the patchset which add wrappers for __lsx_[x]vldx.
>> 
> 
> Just sent the patches:
> https://ffmpeg.org/pipermail/ffmpeg-devel/2022-September/301201.html <https://ffmpeg.org/pipermail/ffmpeg-devel/2022-September/301201.html>
> Can you provide an updated toolchain (with x86 host) able to compile lsx
> and lasx?
> 
> - Andreas

Compiler team haven’t release this version yet(maybe at Sep 13), you can check here :
http://ftp.loongnix.cn/toolchain/gcc/release/loongarch/gcc8/
If you want to try it now, you can update attachment file first.