Optimize color xforms with 2.2 gammas for SSE2
Because we recognize commonly used gamma tables and
parameters as 2.2f, about 98% of jpegs with color profiles
will pass through this xform (assuming the dst is also
2.2f). Sample size is 10,322 jpegs.
I won't go crazy with performance numbers because this is
a work in progress, particularly in terms of correctness.
201295.jpg on HP z620
(300x280, most common form of sRGB profile)
Decode Time + QCMS Xform 1.28 ms
QCMS Xform Only 0.495 ms
Decode Time + Skia Opt Xform 1.01 ms
Skia Opt Xform Only 0.235 ms
Decode Time + Xform Speed-up 1.27x
Xform Only Speed-up 2.11x
FWIW, Skia xform time before these optimizations was
41.1 ms. But we expected that code to be slow.
BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2046013002
CQ_EXTRA_TRYBOTS=client.skia:Test-Ubuntu-GCC-GCE-CPU-AVX2-x86_64-Release-SKNX_NO_SIMD-Trybot
Review-Url: https://codereview.chromium.org/2046013002
6 files changed