Am 31.07.2013 10:13, schrieb Vincenzo Maffione: > This patch partially implements the e1000 interrupt mitigation mechanisms. > Using a single QEMUTimer, it emulates the ITR register (which is the newer > mitigation register, recommended by Intel) and approximately emulates > RADV and TADV registers. TIDV and RDTR register functionalities are not > emulated (RDTR is only used to validate RADV, according to the e1000 specs). > > RADV, TADV, TIDV and RDTR registers make up the older e1000 mitigation > mechanism and would need a timer each to be completely emulated. However, > a single timer has been used in order to reach a good compromise between > emulation accuracy and simplicity/efficiency. > > The implemented mechanism can be enabled/disabled specifying the command > line e1000-specific boolean parameter "mit", e.g.
"mitigation" in example and property definitions below. > > qemu-system-x86_64 -device e1000,mitigation=on,... ... > > For more information, see the Software developer's manual at > http://download.intel.com/design/network/manuals/8254x_GBe_SDM.pdf. > > 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 > > Signed-off-by: Vincenzo Maffione <v.maffi...@gmail.com> > --- > hw/net/e1000.c | 131 > +++++++++++++++++++++++++++++++++++++++++++++++++++++++-- > 1 file changed, 128 insertions(+), 3 deletions(-) > > diff --git a/hw/net/e1000.c b/hw/net/e1000.c > index fdb1f89..32014c2 100644 > --- a/hw/net/e1000.c > +++ b/hw/net/e1000.c [...] > @@ -1385,6 +1508,8 @@ static Property e1000_properties[] = { > DEFINE_NIC_PROPERTIES(E1000State, conf), > DEFINE_PROP_BIT("autonegotiation", E1000State, > compat_flags, E1000_FLAG_AUTONEG_BIT, true), > + DEFINE_PROP_BIT("mitigation", E1000State, > + compat_flags, E1000_FLAG_MIT_BIT, true), > DEFINE_PROP_END_OF_LIST(), > }; > Regards, Andreas -- SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg, Germany GF: Jeff Hawn, Jennifer Guild, Felix Imendörffer; HRB 16746 AG Nürnberg