Attached is a patch that I wrote that adds cpu binding. Feel free to add
it to your sources. It's not that usefull, recent linux distros include
a "taskset" command that can bind a task to a given cpu. I needed it for
an older distro.
With regards to the multi-core case: I've always ignored them, I
couldn't find a good/realistic test case.
Thundering herds (i.e.: one task wakes up lots of waiting tasks) is at
least for sysv msg and sysv sem lockless: the woken up tasks do not take
any locks, they return immediately to user space.
Additionally, I don't know if the test case is realistic: at least
postgres uses one semaphore for each process/thread, thus waking up
multiple tasks never happens.
Another case would be to bind both tasks to different cpus. I'm not sure
if this happens in real life. Anyone around who knows how other
databases implement locking? Is sysv sem still used?
--
Manfred