Go vs PIL

This is a performance comparison between PIL and Go's image package. See related discussion at go-nuts mailing list.

Run the Python script with:

python to_grayscale.py

Run the Go program with:

go run to_grayscale.go

Sample timings

Here are sample timings from my MacBook Pro Core i7 2.2 GHz. These are timings from one run, not averages, but they're representative enough.

+---------------------------------------------+------------+
|                   | Python, ms | Go, ms     | Go tip, ms |
+===================+============+============+============+
| Image decode      |       3.13 |      15.61 |       6.81 |
| RGBA -> Grayscale |       0.88 |       2.70 |       1.54 |
| Image save        |       6.55 |      33.89 |      24.26 |
+-------------------+------------+------------+------------+
| Total             |      10.56 |      57.50 |      32.65 |
+---------------------------------------------+------------+

$ go version
go version go1.0.2

go tip version
14026:4a9c3b3e39c6

$ python --version
Python 2.7.3

PIL version 1.1.7