On Sat, Aug 25, 2018 at 02:33:03PM +0000, avih wrote:
> Hi,
>
> I noticed that configure can be a bit slow - few minutes on my macOS
> system, 1:30m on linux/bash, 30s on linux/dash, and even if
> pathological, still a too-long 10 minutes on Windows (MSYS2) (same
> duration as a full build with make -j4 after configure).
>
> I added some timing information printouts for various parts in
> configure, and eventually identified few culprits.
>
> The attachment "config-timing.patch" adds these printouts and sorted
> summary. It's attached for reference and not intended to be merged.
> It applies cleanly before or after the main patch.
>
>
> The attached "main.patch" addresses three areas I identified as slow:
>
> 1. About 50-70% of configure runtime was being spent inside one
> function: flatten_extralibs() and callees resolve() and unique().
> It manipulates strings and invoked nearly 20K (20000) subshells.
> It was rewritten to avoid subshells, and ended up x50-x250 faster.
>
> 2. print_enabled_components() was invoking sed about 350 times on one
> file. This is never instant but takes many seconds where fork is
> slow (Windows). Invoke sed only once instead = x4-x10 speedup.
>
> 3. After the previous speedups, configure spent 20-60% of its runtime
> at check_deps(). It's particularly slow with bash. After some local
> optimizations - mainly avoid pushvar/popvar and abort early in one
> notable case (empty deps), it's now x4-x25 faster.
>
>
> Some resulting speedups (more details at "before-after.txt"):
>
> - macOS/bash: total: 98s -> 22s flatten_extralibs: 53s -> 0.7s
> - Linux/bash: total: 87s -> 11s flatten_extralibs: 59s -> 0.9s
> - Linux/dash: total: 27s -> 8s flatten_extralibs: 17s -> 0.2s
> - FreeBSD/sh: total: 34s -> 9s flatten_extralibs: 23s -> 0.2s
> - MSYS2/bash: total: 10m -> 2:30m flatten_extralibs: 400s -> 1.5s (!)
>
>
> Notes:
>
> - unique() is modified with flatten_extralibs. It now outputs different
> order: it was keeping the last instance of recurring items, now it
> keeps the first. It affects libs order at ffbuild/config.{mak,sh} -
> but I don't think it matters. If it does, "opt1-reorder-unique.patch"
> restores the original order. Let me know if/why it matters and I'll
> squash it and update the commit message accordingly if required.
>
> - After the check_deps() patch, pushvar() and popvar() are not used but
> I was hesitant to remove them (nice to have). If you think it should
> be removed, the patch "opt2-remove-pushvar.patch" removes them.
>
> - The patches assume POSIX shell and don't use anything "tricky".
> It was tested with dash, bash, busybox-ash, freebsd-sh, ksh93u, mksh.
>
> - Thanks to tmm1 and atomnuker for their help with testing.
>
>
> This is my first mail to this list, and I wasn't sure how to split the
> patches. After asking a veteran, it was suggested to me that I should
> put all of them in one email. Just let me know if you prefer something
> else (dev mailing lists are not my forte...).with the main patch make distclean ; dash ./configure --enable-gpl && make -j12 testprogs fails: LD libavfilter/tests/filtfmts libavformat/libavformat.a(utils.o): In function `av_apply_bitstream_filters': ffmpeg/libavformat/utils.c:5577: undefined reference to `av_bitstream_filter_filter' libavformat/libavformat.a(codec2.o): In function `codec2_read_header_common': ffmpeg/libavformat/codec2.c:74: undefined reference to `avpriv_codec2_mode_bit_rate' ffmpeg/libavformat/codec2.c:75: undefined reference to `avpriv_codec2_mode_frame_size' ffmpeg/libavformat/codec2.c:76: undefined reference to `avpriv_codec2_mode_block_align' ffmpeg/libavformat/codec2.c:74: undefined reference to `avpriv_codec2_mode_bit_rate' ffmpeg/libavformat/codec2.c:75: undefined reference to `avpriv_codec2_mode_frame_size' ffmpeg/libavformat/codec2.c:76: undefined reference to `avpriv_codec2_mode_block_align' libavformat/libavformat.a(spdifdec.o): In function `spdif_get_offset_and_codec': ffmpeg/libavformat/spdifdec.c:63: undefined reference to `av_adts_header_parse' ffmpeg/libavformat/spdifdec.c:63: undefined reference to `av_adts_header_parse' libavformat/libavformat.a(spdifenc.o): In function `spdif_header_aac': ffmpeg/libavformat/spdifenc.c:357: undefined reference to `av_adts_header_parse' collect2: error: ld returned 1 exit status make: *** [libavfilter/tests/filtfmts] Error 1 [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB Freedom in capitalist society always remains about the same as it was in ancient Greek republics: Freedom for slave owners. -- Vladimir Lenin
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