Re: [Qemu-devel] Is network backend netmap worth keeping?

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

On 8/8/19 7:38 AM, Jason Wang wrote:
> 
> On 2019/8/8 下午12:48, Markus Armbruster wrote:
>> Please excuse the attention-grabbing subject.
>>
>> Philippe Mathieu-Daudé <philmd@redhat.com> writes:
>>
>>> On 8/7/19 10:16 PM, Markus Armbruster wrote:
>> [...]
>>>> Can you tell me offhand what I have to install so configure enables
>>>> CONFIG_NETMAP?
>>> The steps are listed in tests/docker/dockerfiles/debian-amd64.docker,
>>> but you can get to this point running:
>>>
>>>    $ make docker-image-debian-amd64 V=1 DEBUG=1
>>>
>>> This will build the docker image with netmap (so you don't have to mess
>>> with your workstation setup), then build QEMU within the image.
>> So, to make use of QEMU's netmap backend (CONFIG_NETMAP), you have to
>> build and install netmap software from sources.  Which pretty much
>> ensures nobody uses it.  It was added in commit 58952137b0b (Nov 2013).
>> The commit message points to <http://info.iet.unipi.it/~luigi/netmap/>,
>> which gives me "connection timed out" right now.
>>
>> On the other hand, it's covered in MAINTAINERS, and has seen
>> non-janitorial activity as late as Dec 2018 (commit c693fc748a).
>>
>> Luigi, Giuseppe, Vincenzo, what's the status of the netmap project?
>>
>> Why is the QEMU netmap backend worth keeping?
>>
>> Who is using the netmap backend?
> 
> 
> Netmap was supported by freebsd:
> https://www.freebsd.org/cgi/man.cgi?query=netmap&sektion=4. So I guess
> there should be real users.
> 
> 
>>
>> How do they obtain a netmap-enabled QEMU?  Compile it from sources
>> themselves?
> 
> 
> Yes.

Hmm at least on the FreeBSD setup by vmtest (12.0-RELEASE r341666) we
don't need to build it from source:

$ make vm-build-freebsd V=1 DEBUG=1
[...]
netmap support    yes
[...]

$ fgrep -r CONFIG_NETMAP .
./config-host.mak:CONFIG_NETMAP=y