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

[Xen-devel] To use xcs or not?

  • To: xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxxxx>
  • From: Jacob Gorm Hansen <jacobg@xxxxxxx>
  • Date: Sun, 20 Feb 2005 00:48:13 -0800
  • Delivery-date: Sun, 20 Feb 2005 08:51:36 +0000
  • List-id: List for Xen developers <xen-devel.lists.sourceforge.net>


I am creating a graphics system where each VM draws into an OpenGL surface of a process running in dom0. I need to syncronize updates, ideally with the vertical blanking of the screen, but in the world of stupid PC hardware probably just with some refresh timer that my OpenGL process is tied to.

So when the screen has been redrawn, I need to wake up my domUs, and for this I wanted to use the ctrl_if mechanism. I borrowed some code from vm-shutdown in the (very nice) vm-tools package, setup a semaphore in the guest kernel, and for every screen update I send an XCS_REQUEST (only type that seems to do anything) up to the domU.

This works fine for a little while (1000 updates or so), whereafter xcs seems to go into an infinite loop. I am going to debug this a little, but before I dig in too dig I would like to know if this is the right solution for my problem. It seems a little worrying (performace wise) that all my notifications need to go via another user space process before reaching their destination. Would it be better to setup a dedicated event channel for this, and would doing so be possible from a user space process in dom0 (naturally I can create a special device node if I need to)?


SF email is sponsored by - The IT Product Guide
Read honest & candid reviews on hundreds of IT Products from real users.
Discover which products truly live up to the hype. Start reading now.
Xen-devel mailing list



Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.