Schedule one job for every thread, and wait on a barrier inside the job
execution function.
v2: avoid alloca (fixes Windows build error)
Reviewed-by: Marek Olšák <marek.olsak@amd.com> (v1)
Fences are now 4 bytes instead of 96 bytes (on my 64-bit system).
Signaling a fence is a single atomic operation in the fast case plus a
syscall in the slow case.
Testing if a fence is signaled is the same as before (a simple comparison),
but waiting on a fence is now no more expensive than just testing it in
the fast (already signaled) case.
v2:
- style fixes
- use p_atomic_xxx macros with the right barriers
Acked-by: Marek Olšák <marek.olsak@amd.com>
Consider the following situation:
mtx_lock(mutex);
do_something();
util_queue_add_job(...);
mtx_unlock(mutex);
If the queue is full, util_queue_add_job will wait for a free slot.
If the job which is currently being executed tries to lock the mutex,
it will be stuck forever, because util_queue_add_job is stuck.
The deadlock can be trivially resolved by increasing the queue size
(reallocating the queue) in util_queue_add_job if the queue is full.
Then util_queue_add_job becomes wait-free.
radeonsi will use it.
Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>
for HUD integration in following commits. This valuable profiling data
will allow us to see on the HUD how well glthread is able to utilize
parallelism. This is better than benchmarking, because you can see
exactly what's happening and you don't have to be CPU-bound.
u_threaded_context has the same counters.
Reviewed-by: Timothy Arceri <tarceri@itsqueeze.com>
