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 ESMTPS id E8D854CE40 for ; Wed, 14 May 2025 16:40:15 +0000 (UTC) Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id A147568CB41; Wed, 14 May 2025 19:40:11 +0300 (EEST) Received: from relay1-d.mail.gandi.net (relay1-d.mail.gandi.net [217.70.183.193]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTPS id 783DC68C432 for ; Wed, 14 May 2025 19:40:05 +0300 (EEST) Received: by mail.gandi.net (Postfix) with ESMTPSA id B147543A76; Wed, 14 May 2025 16:40:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=niedermayer.cc; s=gm1; t=1747240804; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=HOLKLXWugZiePqFAnnVxsBoKZYNBr85kfqhcXjgqwLI=; b=Iyl5CPU2RzcfOUd1AS6Oqc1ZlQske1Vf+qACT8rjrkcA4vM2GdsIRU0X8wTTVyX/wJjHCn b/YCg+mT4NKCy99EVrixmzWc2v4mx0gCmLeoigt+RjhlssNMdpsMG2D18T1NqIeesPPw77 UG7OgpuL8tn28KKBL5u5Xb0HZGyZdKcEIg3xLh/AoLf7/63oJREmG8o0rq6ohXyMvHFRR3 FnxCemKamsM4KpIQX16P8g/evhsFDAcf6WXj7YuBKXdxCZLFAVS/j1vs+C+Tr6Gu5bKwIb fOR8ixnXAJtqdHC2oIBTcp0fqWmhOXVPih1u4VXRtZnYwWMlTpl05XrRaNjiKw== Date: Wed, 14 May 2025 18:40:03 +0200 From: Michael Niedermayer To: FFmpeg development discussions and patches Message-ID: <20250514164003.GL29660@pb2> References: MIME-Version: 1.0 In-Reply-To: X-GND-State: clean X-GND-Score: -70 X-GND-Cause: gggruggvucftvghtrhhoucdtuddrgeefvddrtddtgdeftdejgeelucetufdoteggodetrfdotffvucfrrhhofhhilhgvmecuifetpfffkfdpucggtfgfnhhsuhgsshgtrhhisggvnecuuegrihhlohhuthemuceftddunecusecvtfgvtghiphhivghnthhsucdlqddutddtmdenfghrlhcuvffnffculdeftddmnecujfgurhepfffhvfevuffkfhggtggujgesghdtreertddtvdenucfhrhhomhepofhitghhrggvlhcupfhivgguvghrmhgrhigvrhcuoehmihgthhgrvghlsehnihgvuggvrhhmrgihvghrrdgttgeqnecuggftrfgrthhtvghrnhepledtieehtdfhuedthfegjedtleevgfduffduvddufffgtdehtddugeduiefhjedtnecukfhppeeguddrieeirdeijedruddufeenucevlhhushhtvghrufhiiigvpedtnecurfgrrhgrmhepihhnvghtpeeguddrieeirdeijedruddufedphhgvlhhopehlohgtrghlhhhoshhtpdhmrghilhhfrhhomhepmhhitghhrggvlhesnhhivgguvghrmhgrhigvrhdrtggtpdhnsggprhgtphhtthhopedvpdhrtghpthhtohepfhhfmhhpvghgqdguvghvvghlsehffhhmphgvghdrohhrghdprhgtphhtthhopeevhhhithhrrgdrffgvhiesmhhitghrohhsohhfthdrtghomh X-GND-Sasl: michael@niedermayer.cc Subject: Re: [FFmpeg-devel] [PATCH] Boost FPS and performance: Optimize vertical loop for cache-friendly access [libavcodec/jpeg2000dwt.c:dwt_decode97_float] 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: Chitra Dey Sarkar Content-Type: multipart/mixed; boundary="===============7791379803480032390==" Errors-To: ffmpeg-devel-bounces@ffmpeg.org Sender: "ffmpeg-devel" Archived-At: List-Archive: List-Post: --===============7791379803480032390== Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="c60Aklyj4jgaOXzU" Content-Disposition: inline --c60Aklyj4jgaOXzU Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi Chitra On Wed, May 14, 2025 at 03:55:59AM +0000, Chitra Dey Sarkar via ffmpeg-deve= l wrote: > Original Implementation: > --------------------------------- > In the original implementation, the "VER_SD" section processes image data= stored in *data using strided memory access in a vertical fashion This lea= ds to inefficient memory access patterns and cache thrashing due to non-seq= uential data access across multiple inner loops. >=20 > Proposed Refactor: > --------------------------------- > The proposed refactor replaces this by allocating a cache-friendly 2D ar= ray buffer. This change eliminates strided memory access across the three i= nner loops, significantly improving cache locality and reducing cache thras= hing. >=20 > Additionally, the data is transposed outside the lp loop, which allows fo= r efficient per-line access and write-back to the l buffer, further optimiz= ing performance. >=20 > Performance improvements > ------------------------------------------------------- > This change results in a substantial performance improvement Sharing the= FPS data benchmarked on our end for the file 'Tears of Steel' using HandBr= ake >=20 > Device / CPU Model Official FPS = Optimized FPS % Improvement > Surface Laptop 11 (10-core X1P64100, L2: 36MB) 3.18 = 6.15 +93% > Surface Laptop 11(10-core X1P64100, L2: 36MB) 5.16 7.31 = +41% > Surface Laptop 11 (10-core X1P64100, L2: 36MB) 5.57 = 9.21 +65% > AMD Ryzen + NVIDIA RTX 4060 Laptop (12C/24T) 9.97 = 11.22 +12% > Mac Mini Apple M4 Chip 9.00 12= =2E00 +30% >=20 > -------------------------------------------------------------------------= ------------------------------ > --- > libavcodec/jpeg2000dwt.c | 72 +++++++++++++++++++++++++++++++--------- > 1 file changed, 57 insertions(+), 15 deletions(-) >=20 > diff --git a/libavcodec/jpeg2000dwt.c b/libavcodec/jpeg2000dwt.c index 9e= e8122658..45d7897893 100644 > --- a/libavcodec/jpeg2000dwt.c > +++ b/libavcodec/jpeg2000dwt.c > @@ -409,6 +409,15 @@ static void dwt_decode97_float(DWTContext *s, float = *t) > /* position at index O of line range [0-5,w+5] cf. extend function */ > line +=3D 5; >=20 > + /* Find the largest lv and lv to allocate a 2D Array*/ lv and lv ? you mean lv anf lh ? > + int max_dim =3D 0; > + for (lev =3D 0; lev < s->ndeclevels; lev++) { > + if (s->linelen[lev][0] > max_dim) max_dim =3D s->linelen[lev][0= ]; > + if (s->linelen[lev][1] > max_dim) max_dim =3D s->linelen[lev][1]; FFMAX() > + } > + float *array2DBlock =3D av_malloc(max_dim * max_dim * sizeof(float)); > + int useFallback =3D !array2DBlock; also is this supposed to be max_dim_h * max_dim_v ? > + > for (lev =3D 0; lev < s->ndeclevels; lev++) { > int lh =3D s->linelen[lev][0], > lv =3D s->linelen[lev][1], > @@ -431,23 +440,56 @@ static void dwt_decode97_float(DWTContext *s, float= *t) > for (i =3D 0; i < lh; i++) > data[w * lp + i] =3D l[i]; > } > - > - // VER_SD > - l =3D line + mv; > - for (lp =3D 0; lp < lh; lp++) { > - int i, j =3D 0; > - // copy with interleaving > - for (i =3D mv; i < lv; i +=3D 2, j++) > - l[i] =3D data[w * j + lp]; > - for (i =3D 1 - mv; i < lv; i +=3D 2, j++) > - l[i] =3D data[w * j + lp]; > - > - sr_1d97_float(line, mv, mv + lv); this should be run linewise not columnwise if you dont understand what i mean here, please say so and ill elaborate But basically both vertical and horizontal transforms should be done with row based implementations The code before loads and safes each column (which is bad) your code adds an efficient transpose and then copies each row Theres a ton of unneeded copying here, i think the data in your implementation now is copied 4 times for each vertical transform pass But iam very happy to see a patch submission from Microsoft! :) thx [...] --=20 Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB "I am not trying to be anyone's saviour, I'm trying to think about the future and not be sad" - Elon Musk --c60Aklyj4jgaOXzU Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iF0EABEKAB0WIQSf8hKLFH72cwut8TNhHseHBAsPqwUCaCTHXAAKCRBhHseHBAsP q7lNAJ9/ce7NtMvhIWHauQaULNQm/NF+zgCfS70wNE/6DnJiNTWIIw7FJy5+9Hc= =GDVo -----END PGP SIGNATURE----- --c60Aklyj4jgaOXzU-- --===============7791379803480032390== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ 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". --===============7791379803480032390==--