The default vn_relax is mainly targeting Vulkan commands expecting a
rely like object creation and property queries. The defined relax reason
here is VN_RELAX_REASON_RING_SPACE. The polling strategy involves more
busy waits to overcome sleep penalty affecting cpu utilization, as well
as an edge case for Android system server which forces to sleep longer
even with trivial hrtimer interval.
However, for the below relax reasons:
- VN_RELAX_REASON_RING_SPACE
- VN_RELAX_REASON_FENCE
- VN_RELAX_REASON_SEMAPHORE
- VN_RELAX_REASON_QUERY
It's a waste of cpu cycles if we do more busy waits if the initial
polled signals are not "ready". Having less busy waits there allows to
jump to higher order of sleeps sooner to disturb the scheduler less
until signaled.
Signed-off-by: Yiwei Zhang <zzyiwei@chromium.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/28287>
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