From patchwork Tue Jan 15 22:33:03 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Michael Niedermayer X-Patchwork-Id: 11764 Return-Path: X-Original-To: patchwork@ffaux-bg.ffmpeg.org Delivered-To: patchwork@ffaux-bg.ffmpeg.org Received: from ffbox0-bg.mplayerhq.hu (ffbox0-bg.ffmpeg.org [79.124.17.100]) by ffaux.localdomain (Postfix) with ESMTP id 7E36844CFF1 for ; Wed, 16 Jan 2019 00:33:09 +0200 (EET) Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id 9DDC868A976; Wed, 16 Jan 2019 00:32:57 +0200 (EET) X-Original-To: ffmpeg-devel@ffmpeg.org Delivered-To: ffmpeg-devel@ffmpeg.org Received: from relay12.mail.gandi.net (relay12.mail.gandi.net [217.70.178.232]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTPS id 15B1868A773 for ; Wed, 16 Jan 2019 00:32:51 +0200 (EET) Received: from localhost (213-47-41-20.cable.dynamic.surfer.at [213.47.41.20]) (Authenticated sender: michael@niedermayer.cc) by relay12.mail.gandi.net (Postfix) with ESMTPSA id C0E09200002 for ; Tue, 15 Jan 2019 22:33:04 +0000 (UTC) Date: Tue, 15 Jan 2019 23:33:03 +0100 From: Michael Niedermayer To: FFmpeg development discussions and patches Message-ID: <20190115223303.GH3501@michaelspb> References: <20181225221522.18064-1-michael@niedermayer.cc> <20181226193700.GB3501@michaelspb> <20181228165141.GI3501@michaelspb> MIME-Version: 1.0 In-Reply-To: User-Agent: Mutt/1.5.24 (2015-08-30) Subject: Re: [FFmpeg-devel] [PATCH 1/3] avutil/imgutils: Optimize writing 4 bytes in memset_bytes() X-BeenThere: ffmpeg-devel@ffmpeg.org X-Mailman-Version: 2.1.20 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 Errors-To: ffmpeg-devel-bounces@ffmpeg.org Sender: "ffmpeg-devel" On Sun, Dec 30, 2018 at 07:15:49PM +0100, Marton Balint wrote: > > > On Fri, 28 Dec 2018, Michael Niedermayer wrote: > > >On Wed, Dec 26, 2018 at 10:16:47PM +0100, Marton Balint wrote: > >> > >> > >>On Wed, 26 Dec 2018, Paul B Mahol wrote: > >> > >>>On 12/26/18, Michael Niedermayer wrote: > >>>>On Wed, Dec 26, 2018 at 04:32:17PM +0100, Paul B Mahol wrote: > >>>>>On 12/25/18, Michael Niedermayer wrote: > >>>>>>Fixes: Timeout > >>>>>>Fixes: > >>>>>>11502/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_WCMV_fuzzer-5664893810769920 > >>>>>>Before: Executed > >>>>>>clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_WCMV_fuzzer-5664893810769920 > >>>>>>in 11294 ms > >>>>>>After : Executed > >>>>>>clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_WCMV_fuzzer-5664893810769920 > >>>>>>in 4249 ms > >>>>>> > >>>>>>Found-by: continuous fuzzing process > >>>>>>https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg > >>>>>>Signed-off-by: Michael Niedermayer > >>>>>>--- > >>>>>> libavutil/imgutils.c | 6 ++++++ > >>>>>> 1 file changed, 6 insertions(+) > >>>>>> > >>>>>>diff --git a/libavutil/imgutils.c b/libavutil/imgutils.c > >>>>>>index 4938a7ef67..cc38f1e878 100644 > >>>>>>--- a/libavutil/imgutils.c > >>>>>>+++ b/libavutil/imgutils.c > >>>>>>@@ -529,6 +529,12 @@ static void memset_bytes(uint8_t *dst, size_t > >>>>>>dst_size, > >>>>>>uint8_t *clear, > >>>>>> } > >>>>>> } else if (clear_size == 4) { > >>>>>> uint32_t val = AV_RN32(clear); > >>>>>>+ uint64_t val8 = val * 0x100000001ULL; > >>>>>>+ for (; dst_size >= 32; dst_size -= 32) { > >>>>>>+ AV_WN64(dst , val8); AV_WN64(dst+ 8, val8); > >>>>>>+ AV_WN64(dst+16, val8); AV_WN64(dst+24, val8); > >>>>>>+ dst += 32; > >>>>>>+ } > >>>>>> for (; dst_size >= 4; dst_size -= 4) { > >>>>>> AV_WN32(dst, val); > >>>>>> dst += 4; > >>>>>>-- > >>>>>>2.20.1 > >>>>>> > >>>>> > >>>>>NAK, implement special memset function instead. > >>>> > >>>>I can move the added loop into a seperate function, if thats what you > >>>>suggest ? > >>> > >>>No, don't do that. > >>> > >>>>All the code is already in a "special" memset though, this is > >>>>memset_bytes() > >>>> > >>> > >>>I guess function is less useful if its static. So any duplicate should > >>>be avoided in codebase. > >> > >>Isn't av_memcpy_backptr does almost exactly what is needed here? That can > >>also be optimized further if needed. > > > >av_memcpy_backptr() copies data with overlap, its more like a recursive > >memmove(). > > So? As far as I see the memset_bytes function in imgutils.c can be replaced > with this: > > if (clear_size > dst_size) > clear_size = dst_size; > memcpy(dst, clear, clear_size); > av_memcpy_backptr(dst + clear_size, clear_size, dst_size - clear_size); > > I am not against an av_memset_bytes API addition, but I believe it should > share code with av_memcpy_backptr to avoid duplication. ive implemented this, it does not seem to be really faster in the testcase patches below for reference: From 30549c4e674abce48608d99ed3e7f8ccbd557ada Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Tue, 25 Dec 2018 23:15:20 +0100 Subject: [PATCH] avutil/imgutils: Optimize writing 4 bytes in memset_bytes() Fixes: Timeout Fixes: 11502/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_WCMV_fuzzer-5664893810769920 Before: Executed clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_WCMV_fuzzer-5664893810769920 in 11294 ms After : Executed clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_WCMV_fuzzer-5664893810769920 in 4249 ms Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer --- libavutil/imgutils.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/libavutil/imgutils.c b/libavutil/imgutils.c index 4938a7ef67..6c0d3950de 100644 --- a/libavutil/imgutils.c +++ b/libavutil/imgutils.c @@ -529,6 +529,14 @@ static void memset_bytes(uint8_t *dst, size_t dst_size, uint8_t *clear, } } else if (clear_size == 4) { uint32_t val = AV_RN32(clear); +#if HAVE_FAST_64BIT + uint64_t val8 = val * 0x100000001ULL; + for (; dst_size >= 32; dst_size -= 32) { + AV_WN64(dst , val8); AV_WN64(dst+ 8, val8); + AV_WN64(dst+16, val8); AV_WN64(dst+24, val8); + dst += 32; + } +#endif for (; dst_size >= 4; dst_size -= 4) { AV_WN32(dst, val); dst += 4; -- 2.20.1 From 8e5140bf92d7e41090bfca1c6163f9c428402904 Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Tue, 25 Dec 2018 23:15:20 +0100 Subject: [PATCH] avutil/imgutils: Optimize memset_bytes() by using av_memcpy_backptr() This is strongly based on code by Marton Balint Fixes: Timeout Fixes: 11502/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_WCMV_fuzzer-5664893810769920 Before: Executed clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_WCMV_fuzzer-5664893810769920 in 11294 ms After: Executed clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_WCMV_fuzzer-5664893810769920 in 10948 ms Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer --- libavutil/imgutils.c | 26 +++++--------------------- 1 file changed, 5 insertions(+), 21 deletions(-) diff --git a/libavutil/imgutils.c b/libavutil/imgutils.c index 4938a7ef67..cf06afde3f 100644 --- a/libavutil/imgutils.c +++ b/libavutil/imgutils.c @@ -521,28 +521,12 @@ static void memset_bytes(uint8_t *dst, size_t dst_size, uint8_t *clear, if (clear_size == 1) { memset(dst, clear[0], dst_size); dst_size = 0; - } else if (clear_size == 2) { - uint16_t val = AV_RN16(clear); - for (; dst_size >= 2; dst_size -= 2) { - AV_WN16(dst, val); - dst += 2; - } - } else if (clear_size == 4) { - uint32_t val = AV_RN32(clear); - for (; dst_size >= 4; dst_size -= 4) { - AV_WN32(dst, val); - dst += 4; - } - } else if (clear_size == 8) { - uint32_t val = AV_RN64(clear); - for (; dst_size >= 8; dst_size -= 8) { - AV_WN64(dst, val); - dst += 8; - } + } else { + if (clear_size > dst_size) + clear_size = dst_size; + memcpy(dst, clear, clear_size); + av_memcpy_backptr(dst + clear_size, clear_size, dst_size - clear_size); } - - for (; dst_size; dst_size--) - *dst++ = clear[pos++ % clear_size]; } // Maximum size in bytes of a plane element (usually a pixel, or multiple pixels