On 5/17/18 4:36 PM, Stephen Hemminger wrote: > On Thu, 17 May 2018 16:22:37 -0600 > dsah...@kernel.org wrote: > >> From: David Ahern <dsah...@gmail.com> >> >> Using iproute2 to create a bridge and add 4094 vlans to it can take from >> 2 to 3 *minutes*. The reason is the extraneous call to ll_name_to_index. >> ll_name_to_index results in an ioctl(SIOCGIFINDEX) call which in turn >> invokes dev_load. If the index does not exist, which it won't when >> creating a new link, dev_load calls modprobe twice -- once for >> netdev-NAME and again for NAME. This is unnecessary overhead for each >> link create. >> >> When ip link is invoked for a new device, there is no reason to >> call ll_name_to_index for the new device. With this patch, creating >> a bridge and adding 4094 vlans takes less than 3 *seconds*. >> >> Signed-off-by: David Ahern <dsah...@gmail.com> > > Yes this looks like a real problem. > Isn't the cache supposed to reduce this? > > Don't like to make lots of special case flags. >
The device does not exist, so it won't be in any cache. ll_name_to_index already checks it though before calling if_nametoindex.
