11 Jul
2025
11 Jul
'25
11:58 a.m.
On Fri, Jul 11, 2025 at 10:32:52AM +0200, Peter Zijlstra wrote:
At some point the low latency folks are going to come hunting you down. Do you have a plan on how to deal with this; or are we throwing up our hands an say, the hardware sucks, deal with it?
If you turn on SVA in a process then all this same invalidation work happens under someone's spinlock even today.. If it becomes a latency problem for someone then it seems to be much bigger than just this bit.
Most likely the answer is that SVA and realtime are not compatible ideas. I know I've had this conversation with some of our realtime people and they have said they don't want to touch SVA because it makes the device latencies indeterminate with possible faults.
Jason