Changes in v2:
- Addressed review comments
- Fixed lockless algorithm (must not dec if negative in addition to if 0)
- Made spinlock irqsave (fences are completed in IRQs)
This patch adds code to allocate semaphores in a dynamic way using
a lockless algorithm.
1. Semaphore BOs
Semaphore BOs are
This patch adds code to allocate semaphores in a dynamic way using
an algorithm with a lockless fast path.
1. Semaphore BOs
Semaphore BOs are BOs containing semaphores. Each is 4KB large and
contains 1024 4-byte semaphores. They are pinned.
Semaphore BOs are allocated on-demand and freed at
Luca Barbieri l...@luca-barbieri.com writes:
This patch adds code to allocate semaphores in a dynamic way using
an algorithm with a lockless fast path.
1. Semaphore BOs
Semaphore BOs are BOs containing semaphores. Each is 4KB large and
contains 1024 4-byte semaphores. They are pinned.
How often do we expect cross-channel sync to kick in? Maybe 2-3 times
per frame? I suspect contentions will be rare enough to make spinlocks
as fast as atomics for all real-life cases, and they don't have such a
high maintainability cost. What do you guys think?
For the case of a single (or a
Luca Barbieri l...@luca-barbieri.com writes:
How often do we expect cross-channel sync to kick in? Maybe 2-3 times
per frame? I suspect contentions will be rare enough to make spinlocks
as fast as atomics for all real-life cases, and they don't have such a
high maintainability cost. What do
Sounds like premature optimization to me. I'm just stating my personal
view here, but I have a feeling a patch with 60% of lines could do very
well the same for most realistic cases.
Perhaps, but really, the only thing you would probably save by using
spinlocks in the fast path is retrying in
On Mon, Feb 01, 2010 at 10:50:09AM +0100, Luca Barbieri wrote:
This patch adds code to allocate semaphores in a dynamic way using
an algorithm with a lockless fast path.
some minor comments below
1. Semaphore BOs
Semaphore BOs are BOs containing semaphores. Each is 4KB large and
