From: Tariq Toukan <tariqt@mellanox.com>
To: "jianchao.wang" <jianchao.w.wang@oracle.com>,
Eric Dumazet <eric.dumazet@gmail.com>,
Tariq Toukan <tariqt@mellanox.com>,
Jason Gunthorpe <jgg@ziepe.ca>
Cc: junxiao.bi@oracle.com, netdev@vger.kernel.org,
linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org,
Saeed Mahameed <saeedm@mellanox.com>
Subject: Re: [PATCH] net/mlx4_en: ensure rx_desc updating reaches HW before prod db updating
Date: Thu, 25 Jan 2018 11:54:31 +0200 [thread overview]
Message-ID: <918db4ec-8c3c-aafa-4be6-0e00a99632e2@mellanox.com> (raw)
In-Reply-To: <89066a75-43db-0f62-f171-70b0abaa8ea0@oracle.com>
On 25/01/2018 8:25 AM, jianchao.wang wrote:
> Hi Eric
>
> Thanks for you kindly response and suggestion.
> That's really appreciated.
>
> Jianchao
>
> On 01/25/2018 11:55 AM, Eric Dumazet wrote:
>> On Thu, 2018-01-25 at 11:27 +0800, jianchao.wang wrote:
>>> Hi Tariq
>>>
>>> On 01/22/2018 10:12 AM, jianchao.wang wrote:
>>>>>> On 19/01/2018 5:49 PM, Eric Dumazet wrote:
>>>>>>> On Fri, 2018-01-19 at 23:16 +0800, jianchao.wang wrote:
>>>>>>>> Hi Tariq
>>>>>>>>
>>>>>>>> Very sad that the crash was reproduced again after applied the patch.
>>>>>
>>>>> Memory barriers vary for different Archs, can you please share more details regarding arch and repro steps?
>>>> The hardware is HP ProLiant DL380 Gen9/ProLiant DL380 Gen9, BIOS P89 12/27/2015
>>>> The xen is installed. The crash occurred in DOM0.
>>>> Regarding to the repro steps, it is a customer's test which does heavy disk I/O over NFS storage without any guest.
>>>>
>>>
>>> What is the finial suggestion on this ?
>>> If use wmb there, is the performance pulled down ?
I want to evaluate this effect.
I agree with Eric, expected impact is restricted, especially after
batching the allocations.
>>
>> Since https://urldefense.proofpoint.com/v2/url?u=https-3A__git.kernel.org_pub_scm_linux_kernel_git_davem_net-2Dnext.git_commit_-3Fid-3Ddad42c3038a59d27fced28ee4ec1d4a891b28155&d=DwICaQ&c=RoP1YumCXCgaWHvlZYR8PZh8Bv7qIrMUB65eapI_JnE&r=7WdAxUBeiTUTCy8v-7zXyr4qk7sx26ATvfo6QSTvZyQ&m=c0oI8duFkyFBILMQYDsqRApHQrOlLY_2uGiz_utcd7s&s=E4_XKmSI0B63qB0DLQ1EX_fj1bOP78ZdeYADBf33B-k&e=
>>
>> we batch allocations, so mlx4_en_refill_rx_buffers() is not called that often.
>>
>> I doubt the additional wmb() will have serious impact there.
>>
I will test the effect (it'll be beginning of next week).
I'll update so we can make a more confident decision.
Thanks,
Tariq
>>
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next prev parent reply other threads:[~2018-01-25 9:54 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-12 3:42 [PATCH] net/mlx4_en: ensure rx_desc updating reaches HW before prod db updating Jianchao Wang
2018-01-12 16:32 ` Jason Gunthorpe
2018-01-12 16:46 ` Eric Dumazet
2018-01-12 19:53 ` Saeed Mahameed
2018-01-12 20:16 ` Eric Dumazet
2018-01-12 21:01 ` Saeed Mahameed
2018-01-12 21:21 ` Eric Dumazet
2018-01-13 19:15 ` Jason Gunthorpe
2018-01-14 2:40 ` jianchao.wang
2018-01-14 9:47 ` Tariq Toukan
2018-01-15 5:50 ` jianchao.wang
2018-01-19 15:16 ` jianchao.wang
2018-01-19 15:49 ` Eric Dumazet
2018-01-21 9:31 ` Tariq Toukan
2018-01-21 16:24 ` Tariq Toukan
2018-01-21 16:43 ` Eric Dumazet
2018-01-22 2:40 ` jianchao.wang
2018-01-22 15:47 ` Jason Gunthorpe
2018-01-23 3:25 ` jianchao.wang
2018-01-22 2:12 ` jianchao.wang
2018-01-25 3:27 ` jianchao.wang
2018-01-25 3:55 ` Eric Dumazet
2018-01-25 6:25 ` jianchao.wang
2018-01-25 9:54 ` Tariq Toukan [this message]
2018-01-27 12:41 ` jianchao.wang
[not found] ` <d9883261-e93e-400a-757c-3a81d8b6aca1@mellanox.com>
2019-01-02 1:43 ` jianchao.wang
2018-01-21 20:40 ` Jason Gunthorpe
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