On 01/30/2019 10:01 PM, Alex Kogan wrote: > In CNA, spinning threads are organized in two queues, a main queue for > threads running on the same socket as the current lock holder, and a > secondary queue for threads running on other sockets. For details, > see https://arxiv.org/abs/1810.05600. > > Note that this variant of CNA may introduce starvation by continuously > passing the lock to threads running on the same socket. This issue > will be addressed later in the series. > > Signed-off-by: Alex Kogan <alex.kogan@xxxxxxxxxx> > Reviewed-by: Steve Sistare <steven.sistare@xxxxxxxxxx> Just wondering if you have tried include PARVIRT_SPINLOCKS option to see if that patch may screw up the PV qspinlock code. Anyway, I do believe your claim that NUMA-aware qspinlock is good for large systems with many nodes. However, all these extra code are overhead for small systems that have a single node/socket, for instance. I will support doing something similar to what had been done to support PV qspinlock. IOW, a separate slowpath function that can be patched to become the default depending on the system being run on or a kernel boot option setting. I would like to keep the core slowpath function simple and easy to understand. So most of the CNA code should be encapsulated into some helper functions and put into a separated file. Thanks, Longman
