On Thu, Jan 30, 2020 at 05:05:28PM -0500, Alex Kogan wrote: > > > On Jan 25, 2020, at 6:19 AM, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote: > > > > On Fri, Jan 24, 2020 at 01:19:05PM -0500, Alex Kogan wrote: > > > >> Is there a lightweight way to identify such a “prioritized” thread? > > > > No; people might for instance care about tail latencies between their > > identically spec'ed worker tasks. > > I would argue that those users need to tune/reduce the intra-node handoff > threshold for their needs. Or disable CNA altogether. I really don't like boot time arguments (or tunables in generic) for a machine to work as it should. The default really should 'just work'. > In general, Peter, seems like you are not on board with the way Longman > suggested to handle prioritized threads. Am I right? Right. Presumably you have a workload where CNA is actually a win? That is, what inspired you to go down this road? Which actual kernel lock is so contended on NUMA machines that we need to do this?
