lavu/riscv: Revert d808070, removing AV_READ_TIME

The implementation of ff_read_time() for RISC-V uses rdtime which has
 precision on existing hardware too low (!) for benchmarking purposes.
Deleting this implementation falls back on clock_gettime() which was
 added as the default ff_read_time() implementation in 33e4cc9.
Below are metrics gathered on SpacemiT K1, before and after this commit:

Before:

$ tests/checkasm/checkasm --bench
benchmarking with native FFmpeg timers
nop: 0.0
checkasm: using random seed 3473665261
checkasm: bench runs 1024 (1 << 10)
RVI:
 - pixblockdsp.get_pixels                [OK]
 - vc1dsp.mspel_pixels                   [OK]
RVF:
 - audiodsp.audiodsp                     [OK]
checkasm: all 4 tests passed
audiodsp.vector_clipf_c: 1388.7
audiodsp.vector_clipf_rvf: 261.5
get_pixels_c: 2.0
get_pixels_rvi: 1.5
vc1dsp.put_vc1_mspel_pixels_tab[0][0]_c: 8.0
vc1dsp.put_vc1_mspel_pixels_tab[0][0]_rvi: 1.0
vc1dsp.put_vc1_mspel_pixels_tab[1][0]_c: 2.0
vc1dsp.put_vc1_mspel_pixels_tab[1][0]_rvi: 0.5

After:

$ tests/checkasm/checkasm --bench
benchmarking with native FFmpeg timers
nop: 56.4
checkasm: using random seed 1021411603
checkasm: bench runs 1024 (1 << 10)
RVI:
 - pixblockdsp.get_pixels                [OK]
 - vc1dsp.mspel_pixels                   [OK]
RVF:
 - audiodsp.audiodsp                     [OK]
checkasm: all 4 tests passed
audiodsp.vector_clipf_c: 23236.4
audiodsp.vector_clipf_rvf: 11038.4
get_pixels_c: 79.6
get_pixels_rvi: 48.4
vc1dsp.put_vc1_mspel_pixels_tab[0][0]_c: 329.6
vc1dsp.put_vc1_mspel_pixels_tab[0][0]_rvi: 38.1
vc1dsp.put_vc1_mspel_pixels_tab[1][0]_c: 89.9
vc1dsp.put_vc1_mspel_pixels_tab[1][0]_rvi: 17.1

Signed-off-by: Rémi Denis-Courmont <remi@remlab.net>

0 files changed, 0 insertions, 0 deletions