From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ffbox0-bg.mplayerhq.hu (ffbox0-bg.ffmpeg.org [79.124.17.100]) by master.gitmailbox.com (Postfix) with ESMTP id 643C540CA6 for ; Wed, 7 Sep 2022 08:57:57 +0000 (UTC) Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id 16CAE68BB61; Wed, 7 Sep 2022 11:57:56 +0300 (EEST) Received: from mail8.parnet.fi (mail8.parnet.fi [77.234.108.134]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTPS id CAB0968B9DF for ; Wed, 7 Sep 2022 11:57:49 +0300 (EEST) Received: from mail9.parnet.fi (mail9.parnet.fi [77.234.108.21]) by mail8.parnet.fi with ESMTP id 2878vk22023446-2878vk23023446; Wed, 7 Sep 2022 11:57:46 +0300 Received: from foo.martin.st (host-97-187.parnet.fi [77.234.97.187]) by mail9.parnet.fi (Postfix) with ESMTPS id A35E2A1407; Wed, 7 Sep 2022 11:57:46 +0300 (EEST) Date: Wed, 7 Sep 2022 11:57:46 +0300 (EEST) From: =?ISO-8859-15?Q?Martin_Storsj=F6?= To: Hubert Mazur In-Reply-To: <20220906102722.53266-3-hum@semihalf.com> Message-ID: References: <20220906102722.53266-1-hum@semihalf.com> <20220906102722.53266-3-hum@semihalf.com> MIME-Version: 1.0 X-FE-Policy-ID: 3:14:2:SYSTEM Subject: Re: [FFmpeg-devel] [PATCH 2/5] lavc/aarch64: Add neon implementation of vsse16 X-BeenThere: ffmpeg-devel@ffmpeg.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: FFmpeg development discussions and patches List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: FFmpeg development discussions and patches Cc: gjb@semihalf.com, upstream@semihalf.com, jswinney@amazon.com, ffmpeg-devel@ffmpeg.org, mw@semihalf.com, spop@amazon.com Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Errors-To: ffmpeg-devel-bounces@ffmpeg.org Sender: "ffmpeg-devel" Archived-At: List-Archive: List-Post: On Tue, 6 Sep 2022, Hubert Mazur wrote: > Provide optimized implementation of vsse16 for arm64. > > Performance comparison tests are shown below. > - vsse_0_c: 254.4 > - vsse_0_neon: 64.7 > > Benchmarks and tests are run with checkasm tool on AWS Graviton 3. > > Signed-off-by: Hubert Mazur > --- > libavcodec/aarch64/me_cmp_init_aarch64.c | 4 ++ > libavcodec/aarch64/me_cmp_neon.S | 87 ++++++++++++++++++++++++ > 2 files changed, 91 insertions(+) > > diff --git a/libavcodec/aarch64/me_cmp_init_aarch64.c b/libavcodec/aarch64/me_cmp_init_aarch64.c > index ddc5d05611..7b81e48d16 100644 > --- a/libavcodec/aarch64/me_cmp_init_aarch64.c > +++ b/libavcodec/aarch64/me_cmp_init_aarch64.c > @@ -43,6 +43,8 @@ int sse4_neon(MpegEncContext *v, const uint8_t *pix1, const uint8_t *pix2, > > int vsad16_neon(MpegEncContext *c, const uint8_t *s1, const uint8_t *s2, > ptrdiff_t stride, int h); > +int vsse16_neon(MpegEncContext *c, const uint8_t *s1, const uint8_t *s2, > + ptrdiff_t stride, int h); > > av_cold void ff_me_cmp_init_aarch64(MECmpContext *c, AVCodecContext *avctx) > { > @@ -62,5 +64,7 @@ av_cold void ff_me_cmp_init_aarch64(MECmpContext *c, AVCodecContext *avctx) > c->sse[2] = sse4_neon; > > c->vsad[0] = vsad16_neon; > + > + c->vsse[0] = vsse16_neon; > } > } > diff --git a/libavcodec/aarch64/me_cmp_neon.S b/libavcodec/aarch64/me_cmp_neon.S > index 1d0b166d69..b3f376aa60 100644 > --- a/libavcodec/aarch64/me_cmp_neon.S > +++ b/libavcodec/aarch64/me_cmp_neon.S > @@ -649,3 +649,90 @@ function vsad16_neon, export=1 > > ret > endfunc > + > +function vsse16_neon, export=1 > + // x0 unused > + // x1 uint8_t *pix1 > + // x2 uint8_t *pix2 > + // x3 ptrdiff_t stride > + // w4 int h > + > + ld1 {v0.16b}, [x1], x3 // Load pix1[0], first iteration > + ld1 {v1.16b}, [x2], x3 // Load pix2[0], first iteration > + > + sub w4, w4, #1 // we need to make h-1 iterations > + movi v16.4s, #0 > + movi v17.4s, #0 > + > + cmp w4, #3 // check if we can make 3 iterations at once > + usubl v31.8h, v0.8b, v1.8b // Signed difference of pix1[0] - pix2[0], first iteration > + usubl2 v30.8h, v0.16b, v1.16b // Signed difference of pix1[0] - pix2[0], first iteration > + b.le 2f > + > + > +1: > + // x = abs(pix1[0] - pix2[0] - pix1[0 + stride] + pix2[0 + stride]) > + // res = (x) * (x) Technically, there's no need for abs() here, we can just as well just do a plain subtraction. I tested this by replacing sabd with sub here (and changing umlal into smlal). It doesn't make any difference for the performance on the cores I tested on though - apparently there's no difference in performance between sabd and sub. So in practice, both should be fine. And I don't think that either of them is better for handling overflows/edge cases here either (which shouldn't be happening anyway). // Martin _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".