From: Stephen Hemminger <stephen@networkplumber.org>
To: dsahern@kernel.org
Cc: netdev@vger.kernel.org, David Ahern <dsahern@gmail.com>
Subject: Re: [PATCH iproute2] ip link: Do not call ll_name_to_index when creating a new link
Date: Thu, 17 May 2018 15:36:04 -0700 [thread overview]
Message-ID: <20180517153604.0d905a36@xeon-e3> (raw)
In-Reply-To: <20180517222237.72388-1-dsahern@kernel.org>
On Thu, 17 May 2018 16:22:37 -0600
dsahern@kernel.org wrote:
> From: David Ahern <dsahern@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 <dsahern@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.
next prev parent reply other threads:[~2018-05-17 22:36 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-17 22:22 [PATCH iproute2] ip link: Do not call ll_name_to_index when creating a new link dsahern
2018-05-17 22:36 ` Stephen Hemminger [this message]
2018-05-17 22:47 ` David Ahern
2018-05-18 0:17 ` David Ahern
2018-05-18 22:08 ` Stephen Hemminger
2018-05-18 23:40 ` David Ahern
2018-05-25 15:21 ` Stephen Hemminger
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