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Hi guys, I'm wondering whether libvirt supports live migration for the VM with PCI passthrough devices. or it must be assumed before live migration that all passthrough devices be unplugged? If so, all unplugged devices should be manually hot-plugged to the VM after migration?? Thanks.

...dumping their internal state and restoring > from it on destination. > > There is a long thread started last month that discuss what the interface > should look like, but at this point I guess we are still far away from it: > > https://www.redhat.com/archives/libvir-list/2020-July/msg00675.html Just a little note, even with such an interface in place it will still take time for vendors of conventional physical devices to adopt it, so realistically the main focus here are mediated devices and SRIOV-capable devices. Erik

...lation. > 1-2% more cases != 1-2% reduction in code size. In particular, it assumes nothing else will catch those cases :) The cases are mostly caught by SimplifyCFG/etc anyway In any case, here are the numbers from when it was turned on by default: https://gcc.gnu.org/ml/gcc-patches/2004-01/msg00675.html Note: GCC is at least 3x faster at computing post-dom than LLVM Also, what exactly is the algorithm using post-dom info? > > So, to review for a second, right now, the algorithm answers the question when is a branch necessary with "always" :) The real answer is "when an...

...1-2% more cases != 1-2% reduction in code size. In particular, it assumes nothing else will catch those cases :) Fair enough. The cases are mostly caught by SimplifyCFG/etc anyway In any case, here are the numbers from when it was turned on by default: https://gcc.gnu.org/ml/gcc-patches/2004-01/msg00675.html Note: GCC is at least 3x faster at computing post-dom than LLVM Why? Also, what exactly is the algorithm using post-dom info? So, to review for a second, right now, the algorithm answers the question when is a branch necessary with "always" :) The real answer is "when an al...

...elves are not capable of dumping their internal state and restoring from it on destination. There is a long thread started last month that discuss what the interface should look like, but at this point I guess we are still far away from it: https://www.redhat.com/archives/libvir-list/2020-July/msg00675.html > > If so, all unplugged devices should be manually hot-plugged to the VM > after migration?? This is the usual mode of operation, yes. Michal

...1-2% more cases != 1-2% reduction in code size. In particular, it assumes nothing else will catch those cases :) Fair enough. The cases are mostly caught by SimplifyCFG/etc anyway In any case, here are the numbers from when it was turned on by default: https://gcc.gnu.org/ml/gcc-patches/2004-01/msg00675.html Note: GCC is at least 3x faster at computing post-dom than LLVM Why? Also, what exactly is the algorithm using post-dom info? So, to review for a second, right now, the algorithm answers the question when is a branch necessary with "always" :) The real answer is "when an al...

.... In particular, it assumes > nothing else will catch those cases :) > > Fair enough. > > > The cases are mostly caught by SimplifyCFG/etc anyway > > In any case, here are the numbers from when it was turned on by default: > > https://gcc.gnu.org/ml/gcc-patches/2004-01/msg00675.html > > Note: GCC is at least 3x faster at computing post-dom than LLVM > > Why? > > > Also, what exactly is the algorithm using post-dom info? >> >> > So, to review for a second, right now, the algorithm answers the question > when is a branch necessary with...

...1-2% more cases != 1-2% reduction in code size. In particular, it assumes nothing else will catch those cases :) Fair enough. The cases are mostly caught by SimplifyCFG/etc anyway In any case, here are the numbers from when it was turned on by default: https://gcc.gnu.org/ml/gcc-patches/2004-01/msg00675.html Note: GCC is at least 3x faster at computing post-dom than LLVM Why? Also, what exactly is the algorithm using post-dom info? So, to review for a second, right now, the algorithm answers the question when is a branch necessary with "always" :) The real answer is "when an al...

Thanks Also I found that some cases are also caught by a specialized routine to remove dead loops which is missing the case I noticed. odavd From: Daniel Berlin <dberlin at dberlin.org<mailto:dberlin at dberlin.org>> Date: Thursday, January 28, 2016 at 8:45 PM To: David Callahan <dcallahan at fb.com<mailto:dcallahan at fb.com>>, LLVM Dev Mailing list <llvm-dev at