Tier1 decoder speed optimizations #783
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Allow these hot functions to be inlined. This boosts decode performance by ~10%.
We can avoid using a loop-up table with some shift arithmetics.
Add a opj_t1_dec_clnpass_step_only_if_flag_not_sig_visit() method that does the job of opj_t1_dec_clnpass_step_only() assuming the conditions are met. And use it in opj_t1_dec_clnpass(). The compiler generates more efficient code.
This is essentially used to shift inside the lut_ctxno_zc, which we can precompute at the beginning of opj_t1_decode_cblk() / opj_t1_encode_cblk()
Addition flag array such that colflags[1+0] is for state of col=0,row=0..3, colflags[1+1] for col=1, row=0..3, colflags[1+flags_stride] for col=0,row=4..7, ... This array avoids too much cache trashing when processing by 4 vertical samples as done in the various decoding steps.
… (of the non VSC case)
…qc_vsc() with loop unrolling
| } | ||
| } /* VSC and BYPASS by Antonin */ | ||
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| static void opj_t1_dec_sigpass_mqc( | ||
| #define opj_t1_dec_sigpass_mqc_internal(t1, bpno, w, h, flags_stride) \ |
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Hi, is it possible to use an inline function here so that debugging is made easier ? like what was done in ae1da37
Timings will have to be checked after that of course.
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This patch series improves T1 decoding speed, resulting in overall decompression time gains typically of 10-15% for operational products
Various tricks used :
Benchmarking:
This has been tested with the following files :
C1: issue135.j2k (fom openjpeg-data, code blocks 32x32)
C2: Bretagne2.j2k (fom openjpeg-data, code blocks 32x32)
C3: 20160307_125117_0c74.jp2 (non public test file, 3 bands, 12 bits, 6600x2200 for band 1, 3300x2200 for bands 2 and 3, code blocks 64x64)
C4: issue135_vsc.jp2 ( issue135.j2k recoded by opj_compress -M 8, code blocks 64x64)
C5: issue135_raw.jp2 ( issue135.j2k recoded by opj_compress -M 1, code blocks 64x64)
C6: S2A_OPER_MSI_L1C_TL_MTI__20150819T171650_A000763_T30SWE_B05.jp2 (Sentinel 2 tile, 5490x5490, 1 band, 12 bits, code blocks 64x64)
Builds done with -DCMAKE_BUILD_TYPE=Release. Times measured are the smallest time of 2 consecutive runs reported by "opj_decompress -i $(INPUT_FILE) -o /tmp/out.ppm" in the "decode time: XXX ms" line
Machine & OS spec: Intel(R) Core(TM) i5 CPU 750 @ 2.67GHz, Linux 64 bit
Same with 32 bit build (-m32) :
This work has been funded by Planet Labs