netdev - Re: [PATCH v2] iproute2: build nsid-name cache only for commands that need it

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Message-ID: <1cced3be-a4d4-ef04-6079-e65755d9975b@6wind.com>
Date:   Fri, 16 Sep 2016 11:13:11 +0200
From:   Nicolas Dichtel <nicolas.dichtel@...nd.com>
To:     Anton Aksola <aakso@....fi>, netdev@...r.kernel.org
Subject: Re: [PATCH v2] iproute2: build nsid-name cache only for commands that
 need it

Le 16/09/2016 à 09:22, Anton Aksola a écrit :
> The calling of netns_map_init() before command parsing introduced
> a performance issue with large number of namespaces.
> 
> As commands such as add, del and exec do not need to iterate through
> /var/run/netns it would be good not no build the cache before executing
> these commands.
> 
> Example:
> unpatched:
> time seq 1 1000 | xargs -n 1 ip netns add
> 
> real    0m16.832s
> user    0m1.350s
> sys    0m15.029s
> 
> patched:
> time seq 1 1000 | xargs -n 1 ip netns add
> 
> real    0m3.859s
> user    0m0.132s
> sys    0m3.205s
> 
> Signed-off-by: Anton Aksola <aakso@....fi>
> ---
There is still some differences:
$ cat test.batch
netns add foo
netns set foo 1234
netns list-id

Before your patch:
$ ip -b test.batch
nsid 1234 (iproute2 netns name: foo)

After your patch:
$ ip -b test.batch
nsid 1234