Google Summer of Code

[Mohit Dhingra]

*Hi Venkatesh,*

Thanks for clarifications and support. I have been looking around for the
problem of VM exits. I think the following project also shares the same
motivation of bringing down the no. of VM exits


*
----------------------------
Thanks & Regards
Mohit Dhingra
+919611190435*


On 21 March 2013 03:00, Venkatesh Srinivas <vsrinivas at ops101.org> wrote:

> On Tue, Mar 05, 2013 at 03:15:12PM +0530, Mohit Dhingra wrote:
>
>> *Hi Venkatesh,*
>>
>>
>> Thanks a lot for a nice explanatory mail!
>>
>> I found the second project quite interesting, just to repeat  --
>> ** virtio-blk currently 'kicks' the host VMM directly from its
>>   strategy() routine; it may make sense to defer this to a taskqueue. This
>>   is a tiny change, but understanding the performance implications may
>>   take a bit longer.
>>
>> As per my understanding, the notification to host through kick() involves
>> the exit of the guest (as per attached paper). Hence, the aim for this
>> project would also be to minimize the exits, or rather instantaneous
>> exits.
>> Deferring it to the task queue should definitely help. Other things that
>> can be done in this project is batching of the buffers before kick() and
>> dynamically deciding how many buffers can be batched together.
>>
>> Also, not all of the times deferring the 'kick' to taskqueue might not be
>> a
>> good idea. Finding those scenarios would be interesting where it helps,
>> and
>> where it is merely an overhead.
>>
>
> Yep, your understanding is correct.
> QEMU and friends generally try to handle batches of requests per-VMexit,
> so sometimes (often) there are wins to deferred 'kicks'.
> On Mon, Mar 11, 2013 at 09:42:08PM +0530, Mohit Dhingra wrote:
>
>>   Hi Venkatesh,
>>   Will you be able to mentor this project? I actually wanted to get
>>   some
>>   more info and hands on before applying for GSoC project. Please also
>>   check
>>   the previous mail and my proposal.
>>
>
> I'd be happy to mentor a project to work on performance of DFly under
> virtualization (KVM or w/e), but this alone would be too small for a
> full GSoC project, I think. Working on a few of the aspects I mentioned
> earlier (or anything you come up with! very strongly encouraged!) would
> be a better fit for a full project.
>  Take care,
> -- vs;
>
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