A deficiency of cairo-perf-trace is that it currently always uses similar
surfaces for new surface which are kindly cleared by Cairo. This does
not accurately reflect the captured trace and introduces large bandwidth
overheads that distort the profiles.
So we introduce a new boilerplate hook so that the targets can create a
surface without incurring additional overheads.
[Fixes the broken partial commit of bf1b08d066e.]
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
This function is supposed to describe the backend in use. The describe
function is optional - and therefore initialized as NULL everywhere.
Note:
It is well known that the xlib backend uses X. What is not known is what
version the server supports or what graphics card it is running on. That
is the information the describe vfunc is supposed to provide.
For the purposes of benchmarking it is useful to run cairo-perf against a
different library from the one it was compiled against. In order to do so,
we need to check that the runtime library contains the required entry
points for our targets - which we can check by using dlsym.
Originally written by Vladimir Vukicevic to investigate using Skia for
Mozilla, it provides a nice integration with a rather interesting code
base. By hooking Skia underneath Cairo it allows us to directly compare
code paths... which is interesting.
[updated by Chris Wilson]
