On Sat, Jan 19, 2019 at 12:28:25AM +0100, Marton Balint wrote: > > > On Thu, 17 Jan 2019, Michael Niedermayer wrote: > > >On Wed, Jan 16, 2019 at 08:00:22PM +0100, Marton Balint wrote: > >> > >> > >>On Tue, 15 Jan 2019, Michael Niedermayer wrote: > >> > >>>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 <mich...@niedermayer.cc> wrote: > >>>>>>>>On Wed, Dec 26, 2018 at 04:32:17PM +0100, Paul B Mahol wrote: > >>>>>>>>>On 12/25/18, Michael Niedermayer <mich...@niedermayer.cc> 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 <mich...@niedermayer.cc> > >>>>>>>>>>--- > >>>>>>>>>>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 > >> > >>I guess it is not faster because you have not applied your original > >>optimalization to fill32 in libavutil/mem.c. Could you compare speed after > >>optimizing that the same way your original patch did it with imgutils > >>memset_bytes? > > > >sure, that makes it faster: > > Thanks, both patches LGTM.
will apply thanks [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB Observe your enemies, for they first find out your faults. -- Antisthenes
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