[Qemu-devel] How to understand the coroutine context?

[Qemu-devel] How to understand the coroutine context?

[Le Tan]

Hi, I am diving into the source code of qemu. I see the word
"coroutine" appears in so many places. I can't figure out what it
means. So, please, can anyone help me, telling me the mechanism or
semantic of "coroutine"? Thanks!

--Le Tan

Re: [Qemu-devel] How to understand the coroutine context?

[Kashyap Chamarthy]

On Tue, Mar 18, 2014 at 07:56:16AM +0800, Le Tan wrote:
> Hi, I am diving into the source code of qemu. I see the word
> "coroutine" appears in so many places. I can't figure out what it
> means. So, please, can anyone help me, telling me the mechanism or
> semantic of "coroutine"? Thanks!

This might be of help --
http://blog.vmsplice.net/2014/01/coroutines-in-qemu-basics.html


-- 
/kashyap

Re: [Qemu-devel] How to understand the coroutine context?

[Le Tan]

Thanks, that is an excellent blog!

2014-03-18 12:04 GMT+08:00 Kashyap Chamarthy <kchamart@redhat.com>:
> On Tue, Mar 18, 2014 at 07:56:16AM +0800, Le Tan wrote:
>> Hi, I am diving into the source code of qemu. I see the word
>> "coroutine" appears in so many places. I can't figure out what it
>> means. So, please, can anyone help me, telling me the mechanism or
>> semantic of "coroutine"? Thanks!
>
> This might be of help --
> http://blog.vmsplice.net/2014/01/coroutines-in-qemu-basics.html
>
>
> --
> /kashyap

Re: [Qemu-devel] How to understand the coroutine context?

[Juan Quintela]

Le Tan <tamlokveer@gmail.com> wrote:
> Hi, I am diving into the source code of qemu. I see the word
> "coroutine" appears in so many places. I can't figure out what it
> means. So, please, can anyone help me, telling me the mechanism or
> semantic of "coroutine"? Thanks!

google, 1st hit, wikipedia:

https://en.wikipedia.org/wiki/Coroutine

A bit short resume:

Getting "user"-threads when you don't have threads.

Later, Juan.

Re: [Qemu-devel] How to understand the coroutine context?

[Markus Armbruster]

Juan Quintela <quintela@redhat.com> writes:

> Le Tan <tamlokveer@gmail.com> wrote:
>> Hi, I am diving into the source code of qemu. I see the word
>> "coroutine" appears in so many places. I can't figure out what it
>> means. So, please, can anyone help me, telling me the mechanism or
>> semantic of "coroutine"? Thanks!
>
> google, 1st hit, wikipedia:
>
> https://en.wikipedia.org/wiki/Coroutine
>
> A bit short resume:
>
> Getting "user"-threads when you don't have threads.

More like getting multiple flows of control even though you don't want
threads.

Re: [Qemu-devel] How to understand the coroutine context?

[Juan Quintela]

Markus Armbruster <armbru@redhat.com> wrote:
> Juan Quintela <quintela@redhat.com> writes:
>
>> Le Tan <tamlokveer@gmail.com> wrote:
>>> Hi, I am diving into the source code of qemu. I see the word
>>> "coroutine" appears in so many places. I can't figure out what it
>>> means. So, please, can anyone help me, telling me the mechanism or
>>> semantic of "coroutine"? Thanks!
>>
>> google, 1st hit, wikipedia:
>>
>> https://en.wikipedia.org/wiki/Coroutine
>>
>> A bit short resume:
>>
>> Getting "user"-threads when you don't have threads.
>
> More like getting multiple flows of control even though you don't want
> threads.

If he don't understand coroutine, you think that flows of control has
any chance? O:-)

Later, Juan.

Re: [Qemu-devel] How to understand the coroutine context?

[Markus Armbruster]

Juan Quintela <quintela@redhat.com> writes:

> Markus Armbruster <armbru@redhat.com> wrote:
>> Juan Quintela <quintela@redhat.com> writes:
>>
>>> Le Tan <tamlokveer@gmail.com> wrote:
>>>> Hi, I am diving into the source code of qemu. I see the word
>>>> "coroutine" appears in so many places. I can't figure out what it
>>>> means. So, please, can anyone help me, telling me the mechanism or
>>>> semantic of "coroutine"? Thanks!
>>>
>>> google, 1st hit, wikipedia:
>>>
>>> https://en.wikipedia.org/wiki/Coroutine
>>>
>>> A bit short resume:
>>>
>>> Getting "user"-threads when you don't have threads.
>>
>> More like getting multiple flows of control even though you don't want
>> threads.
>
> If he don't understand coroutine, you think that flows of control has
> any chance? O:-)

Point taken & LOL

Re: [Qemu-devel] How to understand the coroutine context?

[Leandro Dorileo]

Hi,

On Tue, Mar 18, 2014 at 07:56:16AM +0800, Le Tan wrote:
> Hi, I am diving into the source code of qemu. I see the word
> "coroutine" appears in so many places. I can't figure out what it
> means. So, please, can anyone help me, telling me the mechanism or
> semantic of "coroutine"? Thanks!

If you want to understand the coroutine technique itself take a look
at this page[1], the're two references that may be helpfull.

A friend of mine has described[2] his view on implementing coroutine,
this may be helpfull as well.

[1] - http://www.chiark.greenend.org.uk/~sgtatham/coroutines.html
[2] - http://tia.mat.br/blog/html/2012/09/29/asynchronous_i_o_in_c_with_coroutines.html

Regards...

-- 
Leandro Dorileo

Re: [Qemu-devel] How to understand the coroutine context?

[Thomas Huth]

On Tue, 18 Mar 2014 09:34:56 +0530
Kashyap Chamarthy <kchamart@redhat.com> wrote:

> On Tue, Mar 18, 2014 at 07:56:16AM +0800, Le Tan wrote:
> > Hi, I am diving into the source code of qemu. I see the word
> > "coroutine" appears in so many places. I can't figure out what it
> > means. So, please, can anyone help me, telling me the mechanism or
> > semantic of "coroutine"? Thanks!
> 
> This might be of help --
> http://blog.vmsplice.net/2014/01/coroutines-in-qemu-basics.html

That's a very nice introduction ... Stefan, maybe you could also add
that to the docs directory of the QEMU repository? There does not seem
to be a description of the QEMU coroutines there yet...

 Regards,
  Thomas

Re: [Qemu-devel] How to understand the coroutine context?

[Stefan Hajnoczi]

On Tue, Mar 18, 2014 at 11:28:47PM +0100, Thomas Huth wrote:
> On Tue, 18 Mar 2014 09:34:56 +0530
> Kashyap Chamarthy <kchamart@redhat.com> wrote:
> 
> > On Tue, Mar 18, 2014 at 07:56:16AM +0800, Le Tan wrote:
> > > Hi, I am diving into the source code of qemu. I see the word
> > > "coroutine" appears in so many places. I can't figure out what it
> > > means. So, please, can anyone help me, telling me the mechanism or
> > > semantic of "coroutine"? Thanks!
> > 
> > This might be of help --
> > http://blog.vmsplice.net/2014/01/coroutines-in-qemu-basics.html
> 
> That's a very nice introduction ... Stefan, maybe you could also add
> that to the docs directory of the QEMU repository? There does not seem
> to be a description of the QEMU coroutines there yet...

Have you seen the documentation in include/block/coroutine.h?

Stefan

Re: [Qemu-devel] How to understand the coroutine context?

[Thomas Huth]

On Wed, 19 Mar 2014 11:05:02 +0100
Stefan Hajnoczi <stefanha@redhat.com> wrote:

> On Tue, Mar 18, 2014 at 11:28:47PM +0100, Thomas Huth wrote:
> > On Tue, 18 Mar 2014 09:34:56 +0530
> > Kashyap Chamarthy <kchamart@redhat.com> wrote:
> > 
> > > On Tue, Mar 18, 2014 at 07:56:16AM +0800, Le Tan wrote:
> > > > Hi, I am diving into the source code of qemu. I see the word
> > > > "coroutine" appears in so many places. I can't figure out what it
> > > > means. So, please, can anyone help me, telling me the mechanism or
> > > > semantic of "coroutine"? Thanks!
> > > 
> > > This might be of help --
> > > http://blog.vmsplice.net/2014/01/coroutines-in-qemu-basics.html
> > 
> > That's a very nice introduction ... Stefan, maybe you could also add
> > that to the docs directory of the QEMU repository? There does not seem
> > to be a description of the QEMU coroutines there yet...
> 
> Have you seen the documentation in include/block/coroutine.h?

Yes, but that does not have the nice introduction that you've given in
your blog - that's why I though it might be useful to have that
information in a file in the docs directory, too. Well, it was just an
idea ... if you think the API description in coroutine.h is sufficient,
I am certainly fine with that.

 Regards,
  Thomas

Re: [Qemu-devel] How to understand the coroutine context?

[Stefan Hajnoczi]

On Wed, Mar 19, 2014 at 11:13:56AM +0100, Thomas Huth wrote:
> On Wed, 19 Mar 2014 11:05:02 +0100
> Stefan Hajnoczi <stefanha@redhat.com> wrote:
> 
> > On Tue, Mar 18, 2014 at 11:28:47PM +0100, Thomas Huth wrote:
> > > On Tue, 18 Mar 2014 09:34:56 +0530
> > > Kashyap Chamarthy <kchamart@redhat.com> wrote:
> > > 
> > > > On Tue, Mar 18, 2014 at 07:56:16AM +0800, Le Tan wrote:
> > > > > Hi, I am diving into the source code of qemu. I see the word
> > > > > "coroutine" appears in so many places. I can't figure out what it
> > > > > means. So, please, can anyone help me, telling me the mechanism or
> > > > > semantic of "coroutine"? Thanks!
> > > > 
> > > > This might be of help --
> > > > http://blog.vmsplice.net/2014/01/coroutines-in-qemu-basics.html
> > > 
> > > That's a very nice introduction ... Stefan, maybe you could also add
> > > that to the docs directory of the QEMU repository? There does not seem
> > > to be a description of the QEMU coroutines there yet...
> > 
> > Have you seen the documentation in include/block/coroutine.h?
> 
> Yes, but that does not have the nice introduction that you've given in
> your blog - that's why I though it might be useful to have that
> information in a file in the docs directory, too. Well, it was just an
> idea ... if you think the API description in coroutine.h is sufficient,
> I am certainly fine with that.

I will expand the documentation in include/block/coroutine.h.

Stefan