On Wed, Aug 27, 2008 at 09:49:10AM -0700, Rick Jones wrote:
Andi Kleen wrote:
Those banks really want to crank down on latency - to the point they start disabling interrupt coalescing. I bet they'd toss anything out they could to shave another microsecond.
This change would actually likely lower their latency.
I'm guessing you mean increase their latency? I agree, it could - depends entirely on the PPS in production I suspect.
No, moving the time stamps into the socket decreases latency
for all packets that don't need time stamps. And they likely have some packets which don't need time stamps too.
As a secondary effect if they use a RT kernel it might
be also beneficial to do the (depending on the platform)
costly time stamp in the lower priority socket context
than in the high priority interrupt thread.
-Andi