Within each function that launches tasks, we now can easily track which
tasks that function launched, so that the sync at the end of the function
can just sync on the tasks launched by that function (not all tasks
launched by all functions.)
Implementing this led to a rework of the task system API that ispc generates
code to call; the example task systems in examples/tasksys.cpp have been
updated to conform to this API. (The updated API is also documented in
the ispc user's guide.)
As part of this, "launch[n]" syntax was added to launch a number of tasks
in a single launch statement, rather than requiring a loop over 'n' to
launch n tasks.
This commit thus fixes issue #84 (enhancement to launch multiple tasks from
a single launch statement) as well as issue #105 (recursive task launches
were broken).
This applies a floating-point scale factor to the image resolution;
it's useful for experiments with many-core systems where the
base image resolution may not give enough work for good load-balancing
with tasks.
- Only have a single copy of all of the tasks_*.cpp sample implementations,
stored in examples/.
- Reduce dynamic storage allocation and locking in task launch code paths.
- Don't have a hard limit of the number of tasks that can be launched on
Windows (fix issue #85).
- In the ispc-generated header files, a #define now indicates which compilation target
was used.
- The examples use utility routines from the new file examples/cpuid.h to check the
system's CPU's capabilities to see if it supports the ISA that was used for
compiling the example code and print error messages if things aren't going to
work...
