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

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Message-ID: <CAMw6YJJuoA+Z_DQx8iSEkrurB4ZZN9MePtHEeW=q7t5aDvmSAA@mail.gmail.com>
Date:   Fri, 16 Sep 2016 12:23:54 +0300
From:   Vadim Kochan <vadim4j@...il.com>
To:     Nicolas Dichtel <nicolas.dichtel@...nd.com>
Cc:     Anton Aksola <aakso@....fi>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: Re: [PATCH v2] iproute2: build nsid-name cache only for commands that
 need it

On Fri, Sep 16, 2016 at 12:13 PM, Nicolas Dichtel
<nicolas.dichtel@...nd.com> wrote:
> 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

Would it be useful to add test for this case into testsuite/ ?

Regards,
Vadim Kochan