[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[Qemu-devel] Re: Extending virtio_console to support multiple ports

From: Anthony Liguori
Subject: [Qemu-devel] Re: Extending virtio_console to support multiple ports
Date: Mon, 31 Aug 2009 08:17:21 -0500
User-agent: Thunderbird (X11/20090825)

Amit Shah wrote:
No flags, assume it's a streaming protocol and don't assume anything about message sizes. IOW, when you send clipboard data, send size and then the data. QEMU consumes bytes until it reaches size.

Same intent but a different method: I'll have to specify that particular
data is "size" and that data after this special data is the actual data

Sounds like every stream protocol in existence :-)

- A lock has to be introduced to fetch one unused buffer from the list
  and pass it on to the host. And this lock has to be a spinlock, just
  because writes can be called from irq context.
I don't see a problem here.

You mean you don't see a problem in using a spinlock vs not using one?

Right.  This isn't a fast path.

Userspace will typically send the entire buffer to be transmitted in one
system call. If it's large, the system call will have to be broken into
several. This results in multiple guest system calls, each one to be
handled with a spinlock held.

Compare this with the entire write handled in one system call in the
current method.

Does it matter?  This isn't a fast path.


Anthony Liguori

reply via email to

[Prev in Thread] Current Thread [Next in Thread]