Thanks for the review Arun. > You mean at compile time? Runtime would be interesting as...
The transparent paravirtualization approach I use could be easily extended to support more than one hypervisor selected at runtime. > But the bigger question we haven't answered is: > Is an instruction level approach sufficient to build a high > performance hypervisor? Define "high performance hypervisor"... Would "within a few percent of native" qualify? Xen/ia64 admittedly hasn't gone through a wide range of performance tests but domain0* currently compiles linux at only 4% slower than native and I expect this to get closer to 2% with some more work (and without additional changes to the patch). A domU* guest will be slower due to I/O overhead but I/O is already using higher level primitives (the same ones as x86). Dan * For those not familiar with Xen terminology: domain0: the "host" or "service" virtual machine domU: a "guest" virtual machine > -----Original Message----- > From: Arun Sharma [mailto:[EMAIL PROTECTED] > Sent: Monday, August 22, 2005 3:46 PM > To: Magenheimer, Dan (HP Labs Fort Collins) > Cc: [email protected] > Subject: Re: Xen and the Art of Linux/ia64 Virtualization > > Magenheimer, Dan (HP Labs Fort Collins) wrote: > > Hi Dan, > > > Revision 5. Incorporates abstraction changes to ia64_getreg > > and ia64_setreg as suggested by David Mosberger and Tony > > Luck. Also generalized a bit so that it will be easy to > > support other virtualization software that may come along. > > You mean at compile time? Runtime would be interesting as > well, but that > would mean moving the macros out of line. > > > This patch is currently against 2.6.12 (thus for review only). > > > > Signed-off-by: Dan Magenheimer <[EMAIL PROTECTED]> > > > > The patch looks pretty clean to me (except for the CONFIG_XEN > comment I > sent to xen-merge). But the bigger question we haven't answered is: > > Is an instruction level approach sufficient to build a high > performance > hypervisor? > > This question is being actively debated on the x86 side as > well. If the > answer turns out to be "no" and if after doing some performance > analysis, we conclude that higher level primitives are > needed, then some > of these changes would not be needed (because those privilege > sensitive > instructions have been replaced by a higher level primitive). > > -Arun > - To unsubscribe from this list: send the line "unsubscribe linux-ia64" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
