On 11/27/2015 07:42 PM, Denis V. Lunev wrote: > On 11/27/2015 09:50 AM, Denis V. Lunev wrote: >> On 11/27/2015 09:48 AM, Denis V. Lunev wrote: >>> e1000 driver in Win2k12 is really well rotten. It 100% hangs on >>> shutdown >>> of UP VM under flood ping. The guest checks card state and reinjects >>> itself interrupt in a loop. This is fatal for UP machine. >>> >>> There is no good way to fix this misbehavior but to kludge it. The >>> emulation has interrupt throttling register aka ITR which limits >>> interrupt rate and allows the guest to proceed this phase. >>> There is no problem with this kludge for Linux guests - it adjust the >>> value of it itself. >>> >>> On the other hand according to the initial research in >>> commit e9845f0985f088dd01790f4821026df0afba5795 >>> Author: Vincenzo Maffione <v.maffi...@gmail.com> >>> Date: Fri Aug 2 18:30:52 2013 +0200 >>> >>> e1000: add interrupt mitigation support >>> >>> ... >>> >>> Interrupt mitigation boosts performance when the guest suffers >>> from >>> an high interrupt rate (i.e. receiving short UDP packets at >>> high packet >>> rate). For some numerical results see the following link >>> http://info.iet.unipi.it/~luigi/papers/20130520-rizzo-vm.pdf >>> >>> this should also boost performance a bit. >>> >>> See https://bugzilla.redhat.com/show_bug.cgi?id=874406 for additional >>> details. >>> >>> Signed-off-by: Denis V. Lunev <d...@openvz.org> >>> CC: Vincenzo Maffione <v.maffi...@gmail.com> >>> CC: Stefan Hajnoczi <stefa...@redhat.com> >>> --- >>> hw/net/e1000.c | 3 +++ >>> 1 file changed, 3 insertions(+) >>> >>> diff --git a/hw/net/e1000.c b/hw/net/e1000.c >>> index c877e06..0af528f 100644 >>> --- a/hw/net/e1000.c >>> +++ b/hw/net/e1000.c >>> @@ -447,6 +447,9 @@ static void e1000_reset(void *opaque) >>> e1000_link_down(d); >>> } >>> + /* Throttle interrupts to allow poor Win 2012 to shutdown */ >>> + d->mac_reg[ITR] = 250; >>> + >>> /* Some guests expect pre-initialized RAH/RAL (AddrValid flag >>> + MACaddr) */ >>> d->mac_reg[RA] = 0; >>> d->mac_reg[RA + 1] = E1000_RAH_AV; >> Intel manual says about ITR that " A initial suggested range is >> 651-5580 (28Bh - 15CCh)." >> Should we use something other than 250? :) >> >> http://www.intel.com/content/www/us/en/embedded/products/networking/pci-pci-x-family-gbe-controllers-software-dev-manual.html >> >> >> Den > > Jason, can you look to this? > > I have rechecked MAINTAINERs file and found that > I have missed you here. Sorry :( > > Den >
No problem. But I have a question. What if ITR is disabled?
