On Mon, Oct 05, 2020 at 10:38:17AM +0200, Christoph Hellwig wrote: > On Fri, Oct 02, 2020 at 01:20:35PM -0700, Sagi Grimberg wrote: > >> Well, why would they change it? The whole point of the infrastructure > >> is that there is a single sane affinity setting for a given setup. Now > >> that setting needed some refinement from the original series (e.g. the > >> current series about only using housekeeping cpus if cpu isolation is > >> in use). But allowing random users to modify affinity is just a receipe > >> for a trainwreck. > > > > Well allowing people to mangle irq affinity settings seem to be a hard > > requirement from the discussions in the past. > > > >> So I think we need to bring this back ASAP, as doing affinity right > >> out of the box is an absolute requirement for sane performance without > >> all the benchmarketing deep magic. > > > > Well, it's hard to say that setting custom irq affinity settings is > > deemed non-useful to anyone and hence should be prevented. I'd expect > > that irq settings have a sane default that works and if someone wants to > > change it, it can but there should be no guarantees on optimal > > performance. But IIRC this had some dependencies on drivers and some > > more infrastructure to handle dynamic changes... > > The problem is that people change random settings. We need to generalize > it into a sane API (e.g. the housekeeping CPUs thing which totally makes > sense). I don't see many people jump on the bandwagon, someone should do it, but who will? I personally have no knowledge in that area to do anything meaningful. Thanks
