From: Ferruh Yigit <ferruh.yigit@intel.com>
To: Pascal Mazon <pascal.mazon@6wind.com>, keith.wiles@intel.com
Cc: dev@dpdk.org
Subject: Re: [dpdk-dev] [PATCH 1/6] net/tap: use correct tap name
Date: Tue, 31 Jan 2017 15:38:41 +0000 [thread overview]
Message-ID: <9fa2c783-349c-e20c-0e57-0c24e67a4683@intel.com> (raw)
In-Reply-To: <fcde07c9-44a5-deba-fede-de929e1fff62@6wind.com>
On 1/31/2017 3:30 PM, Pascal Mazon wrote:
> On 01/31/2017 04:28 PM, Ferruh Yigit wrote:
>> On 1/31/2017 2:23 PM, Pascal Mazon wrote:
>>> On 01/31/2017 02:06 PM, Ferruh Yigit wrote:> On 1/31/2017 9:42 AM,
>>> Pascal Mazon wrote:
>>>>> dev->data->name contains "net_tap", the device driver name.
>>>>
>>>> I see what patch does, just as a note to commit log:
>>>>
>>>> AFAIK, "dev->data->name" is device name, and for this case it is
>>>> "net_tap#", like "net_tap0", "net_tap1" ...
>>>>
>>>> "dev->data_drv_name" is the driver name which is "net_tap"
>>>
>>> Indeed, dev->data->name is the device name, looking like "net_tap#",
>>> with number increasing for each vdev.
>>> I'll put the following commit log line if that's ok:
>>>
>>> dev->data->name contains the device name, e.g. "net_tap0".
>>>
>>>>
>>>>> dev->data->dev_private->name contains the actual iface name,
>>>>> e.g. "dtap0".
>>>>
>>>> Right, I agree this is correct comparing "dev->data->name"
>>>>
>>>> But the problem is pmd->name is per eth_dev.
>>>>
>>>> If I read code correct, for multiple queue support, each queue pair will
>>>> create a tap device, so each needs a different name.
>>>>
>>>> So can't just use pmd->name. Need to create a name per queue pair, it
>>>> can be combination of pmd->name + "_" + queue_id? Or can keep a name per
>>>> queue pair, instead of eth_dev.
>>>>
>>>> What do you think?
>>>
>>> Actually that's not exactly how it goes.
>>> Adding a queue to a netdevice requires to open("/dev/net/tun") and setting
>>> TUNSETIFF (through ioctl) on the resulting fd.
>>> That's the important part: queues for a given tap device must set TUNSETIFF
>>> with a common ifreq.ifr_name (in our case, pmd->name).
>>>
>>> This is best explained in the kernel doc, there:
>>
>> Thank you for the clarification.
>> If so, why PMD keeps a fd per queue?
>>
>> Overall, patch looks good except mentioned detail in commit log.
>>
>> I suggest waiting Keith's patch, and rebase this set on top of it.
>>
>> Thanks,
>> ferruh
>>
>>>
>>> [1]
>>> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/networking/tuntap.txt#n108
>>>
>> <...>
>>
>
> I would say it is because dev->{r/t}x_pkt_burst() is done per queue.
> In these functions, we need to make our read() and write() accesses on the
> right fd considering the queue we're required to process.
If fd is same for all queues, it is possible to keep one instance in pmd
private_data, and access it from queues. I think it is confusing to have
multiple copy of it, but I see your point.
>
> I'll wait for Keith's patch, then.
Thanks again.
>
> Best regards,
>
next prev parent reply other threads:[~2017-01-31 15:38 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-31 9:42 Pascal Mazon
2017-01-31 9:42 ` [dpdk-dev] [PATCH 2/6] net/tap: use correct channel for error logs Pascal Mazon
2017-01-31 13:07 ` Ferruh Yigit
2017-01-31 16:58 ` Stephen Hemminger
2017-01-31 17:04 ` Wiles, Keith
2017-01-31 9:42 ` [dpdk-dev] [PATCH 3/6] net/tap: don't set fd value overwritten just below Pascal Mazon
2017-01-31 9:42 ` [dpdk-dev] [PATCH 4/6] net/tap: keep kernel-assigned MAC address Pascal Mazon
2017-01-31 13:13 ` Ferruh Yigit
2017-01-31 9:42 ` [dpdk-dev] [PATCH 5/6] net/tap: display tap name after parsing Pascal Mazon
2017-01-31 13:16 ` Ferruh Yigit
2017-01-31 9:42 ` [dpdk-dev] [PATCH 6/6] net/tap: implement link up and down callbacks Pascal Mazon
2017-01-31 13:21 ` Ferruh Yigit
2017-01-31 14:31 ` Pascal Mazon
2017-01-31 13:06 ` [dpdk-dev] [PATCH 1/6] net/tap: use correct tap name Ferruh Yigit
2017-01-31 14:23 ` Pascal Mazon
2017-01-31 15:28 ` Ferruh Yigit
2017-01-31 15:30 ` Pascal Mazon
2017-01-31 15:38 ` Ferruh Yigit [this message]
2017-01-31 15:44 ` Wiles, Keith
2017-01-31 15:44 ` Pascal Mazon
2017-01-31 16:06 ` Wiles, Keith
2017-01-31 16:39 ` Pascal Mazon
2017-01-31 23:29 ` Wiles, Keith
2017-02-01 8:11 ` Pascal Mazon
2017-02-01 15:25 ` Wiles, Keith
2017-02-01 15:40 ` Pascal Mazon
2017-02-01 15:55 ` Wiles, Keith
2017-02-01 17:50 ` Ferruh Yigit
2017-02-02 8:05 ` Pascal Mazon
2017-02-02 8:25 ` Pascal Mazon
2017-02-02 10:23 ` Ferruh Yigit
2017-01-31 14:52 ` Wiles, Keith
2017-01-31 15:14 ` Ferruh Yigit
2017-01-31 15:19 ` Wiles, Keith
2017-02-02 13:46 ` Wiles, Keith
2017-02-02 16:17 ` [dpdk-dev] [PATCH v2 1/7] " Pascal Mazon
2017-02-02 16:17 ` [dpdk-dev] [PATCH v2 2/7] net/tap: use correct channel for error logs Pascal Mazon
2017-02-02 16:18 ` [dpdk-dev] [PATCH v2 3/7] net/tap: don't set fd value overwritten just below Pascal Mazon
2017-02-02 16:18 ` [dpdk-dev] [PATCH v2 4/7] net/tap: keep kernel-assigned MAC address Pascal Mazon
2017-02-02 16:18 ` [dpdk-dev] [PATCH v2 5/7] net/tap: display tap name after parsing Pascal Mazon
2017-02-02 16:18 ` [dpdk-dev] [PATCH v2 6/7] net/tap: implement link up and down callbacks Pascal Mazon
2017-02-02 16:18 ` [dpdk-dev] [PATCH v2 7/7] net/tap: support promiscuous and allmulti setting Pascal Mazon
2017-02-02 16:23 ` [dpdk-dev] [PATCH v2 1/7] net/tap: use correct tap name Wiles, Keith
2017-02-02 16:24 ` Wiles, Keith
2017-02-02 21:55 ` Ferruh Yigit
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