* Sasha Levin <levinsasha928@xxxxxxxxx> wrote:
> So the basic plan here is to allocate a futex(?) for each VCPU
> thread, and have the writer thread lock all futexes when it needs
> to write?
>
> If we assume we only have one writer thread, it can stay pretty
> simple.
We can use an even simpler and more scalable method:
- writers can 'stop' all other threads, by sending them a
threadpool signal and waiting for each thread to have completed
processing their current work and notifying the writer back that
they have stopped running.
This means that the read-side lock is _zero instructions_, basically
just a barrier() to make sure the compiler does not move instructions
across threadpool functions (it wont).
This method requires that we know about every worker thread - i.e.
no-one does a stray pthread_create() and uses data structures from
there. It also requires that each worker thread can 'stop' within a
reasonable amount of time.
Thanks,
Ingo
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