On Mon, Feb 05, 2024 at 03:31:38PM +0100, David wrote: > On 2/5/24 15:06, Andrew Lunn wrote: > > On Mon, Feb 05, 2024 at 12:44:40PM +0100, David Ventura wrote: > > > During IP auto configuration, some drivers apparently need to wait a > > > certain length of time to settle; as this is not true for all drivers, > > > make this length of time configurable. > > Do you see this problem with multiple drivers, or just one in > > particular. To me this seems like a driver bug, and you are just > > papering over the cracks. > > > > Andrew > I don't know of any drivers that may need to wait -- I noticed > this code path being hit when building a minimal kernel that only > had a virtio network device. > At least for the virtio device, the wait is unnecessary and bloats > the time to boot a minimal kernel from 15ms to 33ms. Looking at the code, a delay has been here a long time, since before git. However, 2011 the delay was changes from 1 second to 10ms. There was a discussion about this at the time: https://lore.kernel.org/netdev/1305696161-18277-1-git-send-email-micha@xxxxxxxxxxxxxx/t/ It was said that ARP and DHCP retries should recover any system where the first transmit/receive gets lost with the change from 1s to 10ms. Maybe after 12 years, its time to try a default of 0ms? I would suggest that is a second patch, which is easy to revert if it all goes horribly wrong. Andrew
