This will finally allow us to very easily add lots of other
tests that will similarly involve iterating over the various
sources and operators of interest.
This commit begins to show the benefits of the reorganization
from the last few commits. Specifically, we don't need a callback
for every run anymore, and now that the cairo_t* is available to
the paint entry function and the size changes only on the outer
loop, (rather than inside cairo_perf_run), there's no need for
the ugly, static cache for the source surface.
This effectively reverts the change made in:
3c407aa80a
The justification is that we want to be able to see the
trends of increasing the image size while keeping the test
the same. But changing the number of iterations in a size-
specific way interferes with that. Also, the standard deviation
is almost always better this way, (though it now varies more
by size).
And as a bonus, the total time required to run the suite is now
less.
This changes the perf test output format to be a little more human friendly,
reporting times in ms instead of seconds. It also adds a test number
that could be used in the future for specifying an explicit test to run
(test number, target surface, test name, and size uniquiely identify
a test).
Also adds a few paint tests.
1. Remove all the alarm/signal code, which just isn't doing what we want for some reason.
Instead, for now we'll simply run for a fixed number of iterations, (perhaps we
can tune that per test later).
2. Before computing mean and stdandard deviation of runs, sort them all and discard the
top and bottom 20% of the values.
Now the standard deviation for the paint test is generally 2% or less.
