From: Li RongQing <roy.qing.li@gmail.com>
To: Pravin Shelar <pshelar@nicira.com>
Cc: netdev <netdev@vger.kernel.org>
Subject: Re: [PATCH][net-next] openvswitch: change the data type of error status to atomic_long_t
Date: Tue, 9 Sep 2014 08:29:56 +0800 [thread overview]
Message-ID: <CAJFZqHzWa=gB8b653KgmGZTpNv83KhAZ3VBYvd+VjchmCkiCbQ@mail.gmail.com> (raw)
In-Reply-To: <CALnjE+pTVVr3dQTnUZqB4vQ=MjhyJ1C859Rkjmf7JOGzVVsb5w@mail.gmail.com>
On Tue, Sep 9, 2014 at 6:26 AM, Pravin Shelar <pshelar@nicira.com> wrote:
> On Sun, Sep 7, 2014 at 2:24 AM, Li RongQing <roy.qing.li@gmail.com> wrote:
>> On Sun, Sep 7, 2014 at 11:44 AM, Pravin Shelar <pshelar@nicira.com> wrote:
>>>> The operation of atomic maybe faster than spin lock.
>>>
>>> What is reason for this change?
>>
>> 1. The operation of atomic maybe faster than spin lock
>> 2. I did not find that tx_dropped/tx_error/.. is protected by spin
>> lock under net dir,
>> sometime tx_dropped is atomic_long_t; sometime it is percpu variable;
>> sometime it is
>> u64,but does not need to protect.
>>
>
> These are error counter and the access is not performance sensitive
> code. So I do not see obvious need to optimize it. Do you have any
> performance number for this patch?
I have no performance number, and did not know how to get the performance
number, since I did not know how to trigger the error packet continually.
But I think atomic is suitable for this condition, it maybe
over-skill to use a spin
lock to protect a single variable, and using atomic can save a spin lock space.
-Roy
next prev parent reply other threads:[~2014-09-09 0:29 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-06 11:06 [PATCH][net-next] openvswitch: change the data type of error status to atomic_long_t roy.qing.li
2014-09-07 3:44 ` Pravin Shelar
2014-09-07 9:24 ` Li RongQing
2014-09-07 23:17 ` David Miller
2014-09-08 11:23 ` Li RongQing
2014-09-08 22:21 ` Cong Wang
2014-09-08 22:26 ` Pravin Shelar
2014-09-09 0:29 ` Li RongQing [this message]
2014-09-09 18:47 ` David Miller
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