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Re: [Qemu-devel] [Qemu-block] [PATCH v2 11/11] block: Only poll block la
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [Qemu-block] [PATCH v2 11/11] block: Only poll block layer fds in bdrv_aio_poll |
Date: |
Fri, 11 Sep 2015 12:46:06 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.1.0 |
On 11/09/2015 12:40, Fam Zheng wrote:
> On Fri, 09/11 11:54, Paolo Bonzini wrote:
>>
>>
>> On 11/09/2015 11:44, Fam Zheng wrote:
>>>>>> That would be a step back. Using GSource is useful because it lets
>>>>>> you integrate libraries such as GTK+.
>>>>>
>>>>> Can we move GTK to a separate GSource thread?
>>>>
>>>> I think that GTK should always run in the main thread, or at least the
>>>> one running the default main loop / GMainContext.
>>>
>>> Yeah it's basically GMainContext staying in the main thread and
>>> block/net/chardev I/O put in a new AioContext thread.
>>
>> Why? The point of an event loop is that you can multiplex everything on
>> the same thread. Unless we have specific needs (e.g. scalability) one
>> thread is the way to go and keep things simple.
>
> The reason is scalability. :)
Scalability of what? If virtio-net or virtio-serial needs to be more
scalable, putting all of them into a non-main-loop thread will not make
things more scalable, because you have a single thread anyway. You'd
need to go BQL-free and allow an arbitrary number.
> Moving things to AIO isn't deviation, it's more about enabling of dataplane
> and
> epoll. That's why block was moved to AioContext, and I think we can do similar
> for net and serial, the difference is that as a start, they don't need to be
> fully BQL-free like virtio-blk and scsi. But by running in an aio_poll() loop,
> they can better performance because of epoll.
Isn't that what your "iohandler.c with AioHandler" already does? True,
it would be epoll-within-poll, not pure poll. But if you need epoll,
you might as well go BQL-free.
Paolo
- Re: [Qemu-devel] [PATCH v2 11/11] block: Only poll block layer fds in bdrv_aio_poll, Fam Zheng, 2015/09/08
- Re: [Qemu-devel] [PATCH v2 11/11] block: Only poll block layer fds in bdrv_aio_poll, Paolo Bonzini, 2015/09/11
- Re: [Qemu-devel] [PATCH v2 11/11] block: Only poll block layer fds in bdrv_aio_poll, Fam Zheng, 2015/09/11
- Re: [Qemu-devel] [Qemu-block] [PATCH v2 11/11] block: Only poll block layer fds in bdrv_aio_poll, Alberto Garcia, 2015/09/11
- Re: [Qemu-devel] [Qemu-block] [PATCH v2 11/11] block: Only poll block layer fds in bdrv_aio_poll, Daniel P. Berrange, 2015/09/11
- Re: [Qemu-devel] [Qemu-block] [PATCH v2 11/11] block: Only poll block layer fds in bdrv_aio_poll, Fam Zheng, 2015/09/11
- Re: [Qemu-devel] [Qemu-block] [PATCH v2 11/11] block: Only poll block layer fds in bdrv_aio_poll, Paolo Bonzini, 2015/09/11
- Re: [Qemu-devel] [Qemu-block] [PATCH v2 11/11] block: Only poll block layer fds in bdrv_aio_poll, Fam Zheng, 2015/09/11
- Re: [Qemu-devel] [Qemu-block] [PATCH v2 11/11] block: Only poll block layer fds in bdrv_aio_poll,
Paolo Bonzini <=
- Re: [Qemu-devel] [Qemu-block] [PATCH v2 11/11] block: Only poll block layer fds in bdrv_aio_poll, Fam Zheng, 2015/09/11
- Re: [Qemu-devel] [Qemu-block] [PATCH v2 11/11] block: Only poll block layer fds in bdrv_aio_poll, Paolo Bonzini, 2015/09/11
- Re: [Qemu-devel] [Qemu-block] [PATCH v2 11/11] block: Only poll block layer fds in bdrv_aio_poll, Fam Zheng, 2015/09/11
- Re: [Qemu-devel] [Qemu-block] [PATCH v2 11/11] block: Only poll block layer fds in bdrv_aio_poll, Paolo Bonzini, 2015/09/11