From: Wang Dong <dong.wang.pro@hotmail.com>
To: Stephen Hemminger <stephen@networkplumber.org>
Cc: "dev@dpdk.org" <dev@dpdk.org>
Subject: Re: [dpdk-dev] [PATCH] ixgbe:Add write memory barrier for recv pkts.
Date: Thu, 16 Apr 2015 19:29:21 +0800 [thread overview]
Message-ID: <BLU436-SMTP2437FD8707F1AE277EBAF0ABFE40@phx.gbl> (raw)
In-Reply-To: <20150415090642.0137f4c9@urahara>
> On Wed, 15 Apr 2015 21:46:27 +0800
> Dong.Wang <dong.wang.pro@hotmail.com> wrote:
>
>> Yes, current implementation works well with IA, and the transmit packets
>> function's rte_wmb() is also unneccessary.
>>
>> But there are two reasons for adding rte_wmb() in recv pkts function:
>> 1) The memory barrier in recv pkts function and xmit pkts function are
>> inconsistent, rte_wmb() should be added to recv pkts function or be
>> removed from xmit pkts function.
>> 2) DPDK will support PowerPC processor (Other developers are working on
>> it), I check the memory ordering of PowerPC, there was no mention of
>> store-store instruction's principle in MPC8544 Reference Manual, only
>> said it is weak memory ordering.
>>
>> So, I think it is neccessary to add rte_wmb() to recv pkts function.
>>
>> Dong
>
> If PowerPC requires additional memory barriers then it should
> introduce a new generic set of memory barrier macros that are no-ops
> on other architectures.
>
> Please don't penalize x86 for places where other CPU's have
> weaker consistency.
>
Yes, put rte_wmb() here will penalize x86, I was inconsiderate of it.
Maybe a new set of memory barrier macros will be introduced, it be
discussed in another thread.
For now, add rte_wmb() is unnessary, I'm waiting for new memory barrier
macros.
Dong
next prev parent reply other threads:[~2015-04-16 11:29 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-11 15:33 WangDong
2015-04-14 22:50 ` Ananyev, Konstantin
2015-04-15 13:46 ` Dong.Wang
2015-04-15 16:06 ` Stephen Hemminger
2015-04-16 11:29 ` Wang Dong [this message]
2015-04-15 22:52 ` Ananyev, Konstantin
2015-04-16 11:36 ` Wang Dong
2015-04-16 15:14 ` Ananyev, Konstantin
2015-04-16 15:55 ` David Marchand
2015-05-05 15:52 ` Dong Wang
2015-04-16 15:55 Dong Wang
2015-04-16 15:58 Dong Wang
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