On Wed, 2020-09-16 at 09:12 -0300, Jason Gunthorpe wrote: > > Also we could make this a variable rather than a constant and > > choose > > a more appropriate set of flags at boot time.... > > It is a function, so it could check the CPU ID for the known broken > devices and block them. Sure, I meant in the abstract way. It's not a hot path so it doesnt have to be a static key. > > > > Why would that be a regression ? > > > > > > Using the WC submission flow when it doesn't work costs something > > > like > > > 10% performance vs using the non-WC flow. > > > > You mean the driver uses a different path to the HW which ahs that > > overhead, not that MMIOs have that overhead right ? > > The different path has overhead of doing extra useless MMIOs because > they don't combine I see. This might have to end up being a TX2 specific hack until the end of times... Cheers, Ben.
