From: David Ahern <dsahern@gmail.com>
To: Eric Dumazet <eric.dumazet@gmail.com>,
David Ahern <dsahern@kernel.org>,
stephen@networkplumber.org
Cc: netdev@vger.kernel.org
Subject: Re: [PATCH iproute2-next] Improve batch times by caching link lookups
Date: Mon, 7 Jan 2019 13:58:31 -0700 [thread overview]
Message-ID: <89099221-ca87-3298-47bf-b8e68403c2b2@gmail.com> (raw)
In-Reply-To: <9f8a0935-2f4c-74e8-038d-61e3b5049f12@gmail.com>
On 1/7/19 1:57 PM, Eric Dumazet wrote:
>
>
> On 01/07/2019 12:41 PM, David Ahern wrote:
>> From: David Ahern <dsahern@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.
next prev parent reply other threads:[~2019-01-07 20:58 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-07 20:41 [PATCH iproute2-next] Improve batch times by caching link lookups David Ahern
2019-01-07 20:57 ` Eric Dumazet
2019-01-07 20:58 ` David Ahern [this message]
2019-01-07 21:06 ` Eric Dumazet
2019-01-07 21:16 ` David Ahern
2019-01-07 21:31 ` Stephen Hemminger
2019-01-07 21:52 ` David Ahern
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