DPDK patches and discussions
 help / color / mirror / Atom feed
From: "谢华伟(此时此刻)" <huawei.xhw@alibaba-inc.com>
To: David Marchand <david.marchand@redhat.com>
Cc: Ferruh Yigit <ferruh.yigit@intel.com>,
	Maxime Coquelin <maxime.coquelin@redhat.com>, dev <dev@dpdk.org>,
	"Burakov, Anatoly" <anatoly.burakov@intel.com>,
	xuemingl@nvidia.com, Gaetan Rivet <grive@u256.net>,
	"Xia, Chenbo" <chenbo.xia@intel.com>
Subject: Re: [dpdk-dev] [PATCH v7 2/2] bus/pci: support MMIO in PCI ioport accessors
Date: Mon, 01 Mar 2021 23:43:50 +0800	[thread overview]
Message-ID: <85a43efe-ef66-54c0-81b4-6e130a987699@alibaba-inc.com> (raw)
In-Reply-To: <CAJFAV8w4qvrazksjvy4=5YUtQwRku_FQDMhhmv59-i8o8Zh-Fg@mail.gmail.com>


On 2021/2/25 17:52, David Marchand wrote:
> On Thu, Feb 25, 2021 at 5:00 AM 谢华伟(此时此刻) <huawei.xhw@alibaba-inc.com> wrote:
>>>>> Is the 'outb_p' to 'outb' conversion intentional? And if so why?
>>>>>
>>>>> Same of the all 'outb_p', 'outw_p', 'outl_p'.
>>>> There is no need to delay for virtio device, as we can see in virtio
>>>> legacy driver.
>>>>
>>>> IMO, the delay is for ugly old device. The device itself should
>>>> assure the previous IO completes when the subsequent IO instruction
>>>> arrives.
>>>>
>>> Can there be any virtio legacy device needing this?
>> The pause version delays sometime by writing to 0x80 debug port. virtio
>> doesn't need this. virtio legacy PMD driver doens't use this.
>>
>> Any device relying on this i think is buggy. How could the device rely
>> on some uncertain cpu cycles to behave correct?
>>
>>> What is the downside of using "pause until the I/O completes" versions?
>> The downside in virtio PMD is a small performance penalty when we use it
>> to notify backend. CPU executes unnecessary serializing IO instruction.
>>
>> I check kernel code, io wrapper for in/out doesn't use p version.
> This change is a fix/optimisation.
> This is a separate topic from adding MMIO support with x86 ioport.
> I would split as a separate patch.

Hi David:

Maybe there is confuse? There is no change. The out/in is added. I don't 
remove _p on purpose.

>
>

  reply	other threads:[~2021-03-01 15:44 UTC|newest]

Thread overview: 61+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-29  3:18 [dpdk-dev] [PATCH v6 0/2] support both PIO and MMIO BAR for legacy device in virtio PMD 谢华伟(此时此刻)
2021-01-29  3:18 ` [dpdk-dev] [PATCH v6 1/2] bus/pci: use PCI standard sysfs entry to get PIO address 谢华伟(此时此刻)
2021-02-03  9:37   ` Maxime Coquelin
2021-02-18  9:33   ` David Marchand
2021-02-21 15:58     ` 谢华伟(此时此刻)
2021-02-24 12:49       ` David Marchand
2021-02-24 15:29         ` 谢华伟(此时此刻)
2021-02-24 17:52           ` David Marchand
2021-03-01 15:47             ` 谢华伟(此时此刻)
2021-03-02 12:31             ` 谢华伟(此时此刻)
2021-01-29  3:18 ` [dpdk-dev] [PATCH v6 2/2] bus/pci: support MMIO in PCI ioport accessors 谢华伟(此时此刻)
2021-02-03  9:37   ` Maxime Coquelin
2021-02-09 14:51   ` Ferruh Yigit
2021-02-19  8:52     ` Ferruh Yigit
2021-02-21 15:45       ` 谢华伟(此时此刻)
2021-02-17  9:06   ` David Marchand
2021-02-17 14:15     ` 谢华伟(此时此刻)
2021-02-18  9:33       ` David Marchand
2021-01-29  3:25 ` [dpdk-dev] [PATCH v6 0/2] support both PIO and MMIO BAR for legacy device in virtio PMD 谢华伟(此时此刻)
2021-02-01  7:43   ` 谢华伟(此时此刻)
2021-02-03  9:37     ` Maxime Coquelin
2021-02-04  2:50       ` 谢华伟(此时此刻)
2021-02-22 17:15 ` [dpdk-dev] [PATCH v7 " 谢华伟(此时此刻)
2021-02-22 17:15   ` [dpdk-dev] [PATCH v7 1/2] bus/pci: use PCI standard sysfs entry to get PIO address 谢华伟(此时此刻)
2021-02-22 17:15   ` [dpdk-dev] [PATCH v7 2/2] bus/pci: support MMIO in PCI ioport accessors 谢华伟(此时此刻)
2021-02-22 17:25     ` Ferruh Yigit
2021-02-23 14:20       ` 谢华伟(此时此刻)
2021-02-24 15:45         ` Ferruh Yigit
2021-02-25  3:59           ` 谢华伟(此时此刻)
2021-02-25  9:52             ` David Marchand
2021-03-01 15:43               ` 谢华伟(此时此刻) [this message]
2021-03-02 13:14                 ` David Marchand
2021-03-03  7:56                   ` 谢华伟(此时此刻)
2021-03-01 16:01   ` [dpdk-dev] [PATCH v8 0/2] support both PIO and MMIO BAR for legacy device in virtio PMD 谢华伟(此时此刻)
2021-03-01 16:01     ` [dpdk-dev] [PATCH v8 1/2] bus/pci: use PCI standard sysfs entry to get PIO address 谢华伟(此时此刻)
2021-03-01 16:01     ` [dpdk-dev] [PATCH v8 2/2] bus/pci: support MMIO in PCI ioport accessors 谢华伟(此时此刻)
2021-03-02 12:48     ` [dpdk-dev] [PATCH v8 0/2] support both PIO and MMIO BAR for legacy device in virtio PMD 谢华伟(此时此刻)
2021-03-02 13:01       ` Ferruh Yigit
2021-03-02 13:17       ` David Marchand
2021-03-03 17:46     ` [dpdk-dev] [PATCH v9 " 谢华伟(此时此刻)
2021-03-03 17:46       ` [dpdk-dev] [PATCH v9 1/2] bus/pci: use PCI standard sysfs entry to get PIO address 谢华伟(此时此刻)
2021-03-03 17:46       ` [dpdk-dev] [PATCH v9 2/2] bus/pci: support MMIO in PCI ioport accessors 谢华伟(此时此刻)
2021-03-03 18:24       ` [dpdk-dev] [PATCH v9 0/2] support both PIO and MMIO BAR for legacy device in virtio PMD Stephen Hemminger
2021-03-04 13:45         ` 谢华伟(此时此刻)
2021-03-03 18:47       ` [dpdk-dev] [PATCH v10 0/2] support both PIO and MMIO BAR for legacy virito device 谢华伟(此时此刻)
2021-03-03 18:47         ` [dpdk-dev] [PATCH v10 1/2] bus/pci: use PCI standard sysfs entry to get PIO address 谢华伟(此时此刻)
2021-03-05 16:17           ` 谢华伟(此时此刻)
2021-03-09  6:22             ` 谢华伟(此时此刻)
2021-03-09  7:44               ` David Marchand
2021-03-03 18:47         ` [dpdk-dev] [PATCH v10 2/2] bus/pci: support MMIO in PCI ioport accessors 谢华伟(此时此刻)
2021-03-10 17:36         ` [dpdk-dev] [PATCH v11 0/2] support both PIO and MMIO BAR for legacy virito device 谢华伟(此时此刻)
2021-03-10 17:36           ` [dpdk-dev] [PATCH v11 1/2] bus/pci: use PCI standard sysfs entry to get PIO address 谢华伟(此时此刻)
2021-03-10 17:36           ` [dpdk-dev] [PATCH v11 2/2] bus/pci: support MMIO in PCI ioport accessors 谢华伟(此时此刻)
2021-03-11  6:42             ` Wang, Haiyue
2021-03-15 10:19               ` David Marchand
2021-03-15 11:25                 ` 谢华伟(此时此刻)
2021-03-15 13:11                 ` Wang, Haiyue
2021-03-11 11:54           ` [dpdk-dev] [PATCH v11 0/2] support both PIO and MMIO BAR for legacy virito device Wang, Yinan
2021-03-12 14:32             ` David Marchand
2021-03-15 14:16           ` David Marchand
2021-03-17  8:12             ` 谢华伟(此时此刻)

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=85a43efe-ef66-54c0-81b4-6e130a987699@alibaba-inc.com \
    --to=huawei.xhw@alibaba-inc.com \
    --cc=anatoly.burakov@intel.com \
    --cc=chenbo.xia@intel.com \
    --cc=david.marchand@redhat.com \
    --cc=dev@dpdk.org \
    --cc=ferruh.yigit@intel.com \
    --cc=grive@u256.net \
    --cc=maxime.coquelin@redhat.com \
    --cc=xuemingl@nvidia.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).