[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH 0 of 12] PV on HVM Xen
On Fri, May 28, 2010 at 03:25:34AM -0700, Boris Derzhavets wrote: > What is an advantage of PV on HVM ? > Pure HVM guests using the Qemu emulated disk/network devices are slow. PV-on-HVM drivers make disk- and network IO fast for HVM guests. > Kernel 2.6.34 with Stefano's patches may be built i believe only on Linux > HVM DomU. > Exactly. They're meant for an upstream kernel, running as Xen HVM guest. > At the same time any recent Linux ( >=24 or >=26) supports PV guest > install ( it's in > mainline for a while). > What i am missing here ? > HVM guests might be faster for some workloads compared to PV guests. Kernel compilation could be one example..ie. workloads spawning a lot of new processes all the time. -- Pasi > Boris. > > --- On Mon, 5/24/10, Stefano Stabellini <Stefano.Stabellini@xxxxxxxxxxxxx> > wrote: > > From: Stefano Stabellini <Stefano.Stabellini@xxxxxxxxxxxxx> > Subject: [Xen-devel] [PATCH 0 of 12] PV on HVM Xen > To: "linux-kernel@xxxxxxxxxxxxxxx" <linux-kernel@xxxxxxxxxxxxxxx> > Cc: "Stefano Stabellini" <Stefano.Stabellini@xxxxxxxxxxxxx>, "Jeremy > Fitzhardinge" <jeremy@xxxxxxxx>, "xen-devel@xxxxxxxxxxxxxxxxxxx" > <xen-devel@xxxxxxxxxxxxxxxxxxx>, "Don Dutile" <ddutile@xxxxxxxxxx>, > "Sheng Yang" <sheng@xxxxxxxxxxxxxxx> > Date: Monday, May 24, 2010, 2:25 PM > > Hi all, > this is another update of the PV on HVM Xen series that addresses > Jeremy's comments. > The platform_pci hooks have been removed, suspend/resume for HVM > domains is now much more similar to the PV case and shares the same > do_suspend function. > Alloc_xen_mmio_hook has been removed has well, now the memory allocation > for > the grant table is done by the xen platform pci driver directly. > The per_cpu xen_vcpu variable is set by a cpu_notifier function so that > secondary vcpus have the variable set correctly no matter what the xen > features are on the host. > The kernel command line option xen_unplug has been renamed to > xen_emul_unplug and the code that makes use of it has been moved to a > separate file (arch/x86/xen/platform-pci-unplug.c). > Xen_unplug_emulated_devices is now able to detect if blkfront, netfront > and the Xen platform PCI driver have been compiled, and set the default > value of xen_emul_unplug accordingly. > The patch "Initialize xenbus device structs with ENODEV as > default" has been removed from the series and it will be sent > separately. > Finally the comments on most of the patches have been improved. > > The series is based on 2.6.34 and supports Xen PV frontends running > in a HVM domain, including netfront, blkfront and the VIRQ_TIMER. > > In order to be able to use VIRQ_TIMER and to improve performances you > need a patch to Xen to implement the vector callback mechanism > for event channel delivery. > > A git tree is also available here: > > git://xenbits.xen.org/people/sstabellini/linux-pvhvm.git > > branch name 2.6.34-pvhvm-v2. > > Cheers, > > Stefano > > _______________________________________________ > Xen-devel mailing list > [1]Xen-devel@xxxxxxxxxxxxxxxxxxx > [2]http://lists.xensource.com/xen-devel > > References > > Visible links > 1. file:///mc/compose?to=Xen-devel@xxxxxxxxxxxxxxxxxxx > 2. http://lists.xensource.com/xen-devel > _______________________________________________ > Xen-devel mailing list > Xen-devel@xxxxxxxxxxxxxxxxxxx > http://lists.xensource.com/xen-devel _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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