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 A537243F1B for ; Thu, 18 Aug 2022 09:17:00 +0000 (UTC) Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id 01D6668B9CD; Thu, 18 Aug 2022 12:16:59 +0300 (EEST) Received: from mail8.parnet.fi (mail8.parnet.fi [77.234.108.134]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTPS id 9EE9168B955 for ; Thu, 18 Aug 2022 12:16:52 +0300 (EEST) Received: from mail9.parnet.fi (mail9.parnet.fi [77.234.108.21]) by mail8.parnet.fi with ESMTP id 27I9GhYj020151-27I9GhYk020151; Thu, 18 Aug 2022 12:16:43 +0300 Received: from foo.martin.st (host-97-187.parnet.fi [77.234.97.187]) by mail9.parnet.fi (Postfix) with ESMTPS id B84C6A144B; Thu, 18 Aug 2022 12:16:43 +0300 (EEST) Date: Thu, 18 Aug 2022 12:16:43 +0300 (EEST) From: =?ISO-8859-15?Q?Martin_Storsj=F6?= To: Hubert Mazur In-Reply-To: <20220816122016.64929-4-hum@semihalf.com> Message-ID: References: <20220816122016.64929-1-hum@semihalf.com> <20220816122016.64929-4-hum@semihalf.com> MIME-Version: 1.0 X-FE-Policy-ID: 3:14:2:SYSTEM Subject: Re: [FFmpeg-devel] [PATCH 3/5] lavc/aarch64: Add neon implementation for pix_abs16_y2 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, 16 Aug 2022, Hubert Mazur wrote: > Provide optimized implementation of pix_abs16_y2 function for arm64. > > Performance comparison tests are shown below. > pix_abs_0_2_c: 317.2 > pix_abs_0_2_neon: 37.5 > > Benchmarks and tests run with checkasm tool on AWS Graviton 3. > > Signed-off-by: Hubert Mazur > --- > libavcodec/aarch64/me_cmp_init_aarch64.c | 3 + > libavcodec/aarch64/me_cmp_neon.S | 75 ++++++++++++++++++++++++ > 2 files changed, 78 insertions(+) > > diff --git a/libavcodec/aarch64/me_cmp_init_aarch64.c b/libavcodec/aarch64/me_cmp_init_aarch64.c > index 955592625a..1c36d3d7cb 100644 > --- a/libavcodec/aarch64/me_cmp_init_aarch64.c > +++ b/libavcodec/aarch64/me_cmp_init_aarch64.c > @@ -29,6 +29,8 @@ int ff_pix_abs16_xy2_neon(MpegEncContext *s, const uint8_t *blk1, const uint8_t > ptrdiff_t stride, int h); > int ff_pix_abs16_x2_neon(MpegEncContext *v, const uint8_t *pix1, const uint8_t *pix2, > ptrdiff_t stride, int h); > +int ff_pix_abs16_y2_neon(MpegEncContext *v, const uint8_t *pix1, const uint8_t *pix2, > + ptrdiff_t stride, int h); Misaligned function declaration. > diff --git a/libavcodec/aarch64/me_cmp_neon.S b/libavcodec/aarch64/me_cmp_neon.S > index 367924b3c2..0ec9c0465b 100644 > --- a/libavcodec/aarch64/me_cmp_neon.S > +++ b/libavcodec/aarch64/me_cmp_neon.S > @@ -404,3 +404,78 @@ function sse4_neon, export=1 > > ret > endfunc > + > +function ff_pix_abs16_y2_neon, export=1 Why place this new function at the bottom of the file, instead of logically following the other preexisting pix_abs16 function? In the version I pushed, I moved it further up > + // x0 unused > + // x1 uint8_t *pix1 > + // x2 uint8_t *pix2 > + // x3 ptrdiff_t stride > + // x4 int h This should be w4. You had fixed this in a couple patches, but missed this one. > + > + // initialize buffers > + movi v29.8h, #0 // clear the accumulator > + movi v28.8h, #0 // clear the accumulator > + movi d18, #0 Unused d18 here too > + add x5, x2, x3 // pix2 + stride > + cmp w4, #4 > + b.lt 2f > + > +// make 4 iterations at once > +1: > + > + // abs(pix1[0], avg2(pix2[0], pix2[0 + stride])) > + // avg2(a, b) = (((a) + (b) + 1) >> 1) > + // abs(x) = (x < 0 ? (-x) : (x)) > + > + ld1 {v1.16b}, [x2], x3 // Load pix2 for first iteration > + ld1 {v2.16b}, [x5], x3 // Load pix3 for first iteration > + urhadd v30.16b, v1.16b, v2.16b // Rounding halving add, first iteration > + ld1 {v0.16b}, [x1], x3 // Load pix1 for first iteration > + uabal v29.8h, v0.8b, v30.8b // Absolute difference of lower half, first iteration This whole first sequence is almost entirely blocking, waiting for the result of the previous operation - did you miss to interleave this with the rest of the operations? Normally I wouldn't bother with minor interleaving details, but here the impact was rather big. I manually reinterleaved the whole function, and got this speedup: Before: Cortex A53 A72 A73 pix_abs_0_2_neon: 153.0 63.7 52.7 After: pix_abs_0_2_neon: 141.0 61.7 51.7 // 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".