On 1/7/19 1:57 PM, Eric Dumazet wrote: > > > On 01/07/2019 12:41 PM, David Ahern wrote: >> From: David Ahern <dsah...@gmail.com> >> >> ip route uses ll_name_to_index to convert the user given device name to an >> index. At the moment ll_name_to_index uses if_nametoindex which is ioctl >> based and does not cache the result. When using a batch file this means >> the same device lookups can be done repeatedly adding unnecessary overhead >> (socket + ioctl call for each device lookup). >> >> Add a new function, ll_link_get, to send a netlink based RTM_GETLINK. If >> successful, cache the result in idx_head and name_head so future lookups >> can re-use the entry. >> >> With this change the time to install routes via a batch file is reduced >> from 30.7 seconds to 17.6 seconds (720,022 routes with 2 ecmp nexthops >> where the nexthop device is given). >> > > What time increase if we have 10,000 devices, and install one route ? > > Caching 10,000 devices would be quite a waste. >
It only lookups up the device if ll_name_to_index is invoked for the device. This is NOT a link dump and cache; it only adds lookups to the cache.
