From e9845f0985f088dd01790f4821026df0afba5795 Mon Sep 17 00:00:00 2001 From: Vincenzo Maffione Date: Fri, 2 Aug 2013 18:30:52 +0200 Subject: e1000: add interrupt mitigation support MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 "mitigation", e.g. 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 Reviewed-by: Andreas Färber (for pc-* machines) Signed-off-by: Stefan Hajnoczi --- include/hw/i386/pc.h | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'include') diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h index 7fb04d8cd8..9b2ddc4acc 100644 --- a/include/hw/i386/pc.h +++ b/include/hw/i386/pc.h @@ -225,7 +225,15 @@ void pvpanic_init(ISABus *bus); int e820_add_entry(uint64_t, uint64_t, uint32_t); +#define PC_COMPAT_1_6 \ + {\ + .driver = "e1000",\ + .property = "mitigation",\ + .value = "off",\ + } + #define PC_COMPAT_1_5 \ + PC_COMPAT_1_6, \ {\ .driver = "Conroe-" TYPE_X86_CPU,\ .property = "model",\ -- cgit v1.2.3