Hi Nicholas, Adding Vadim Rozenfeld who wrote the virtio-scsi driver. Best regards, Yan. On Feb 7, 2014, at 10:14 PM, Nicholas A. Bellinger <nab@xxxxxxxxxxxxxxx> wrote: > Hi Yan, > > So recently I've been doing some KVM guest performance comparisons > between the scsi-mq prototype using virtio-scsi + vhost-scsi, and > Windows Server 2012 with vioscsi.sys (virtio-win-0.1-74.iso) + > vhost-scsi using PCIe flash backend devices. > > I've noticed that small block random performance for the MSFT guest is > at around ~80K IOPs with multiple vioscsi LUNs + adapters, which ends up > being well below what the Linux guest with scsi-mq + virtio-scsi is > capable of (~500K). > > After searching through the various vioscsi registry settings, it > appears that MSIEnabled is being explicitly disabled (0x00000000), that > is different from what vioscsi.inx is currently defining: > > [pnpsafe_pci_addreg_msix] > HKR, "Interrupt Management",, 0x00000010 > HKR, "Interrupt Management\MessageSignaledInterruptProperties",, 0x00000010 > HKR, "Interrupt Management\MessageSignaledInterruptProperties", MSISupported, 0x00010001, 0 > HKR, "Interrupt Management\MessageSignaledInterruptProperties", MessageNumberLimit, 0x00010001, 4 > > Looking deeper at vioscsi.c code, I've noticed that MSI_SUPPORTED=0 is > explicitly disabled at build time in SOURCES + vioscsi.vcxproj, as well > as VioScsiFindAdapter() code always ends setting msix_enabled = FALSE > here, regardless of MSI_SUPPORTED: > > https://github.com/YanVugenfirer/kvm-guest-drivers-windows/blob/master/vioscsi/vioscsi.c#L340 > > Also looking at virtio_stor.c for the raw block driver, MSI_SUPPORTED=1 > appears to be the default setting for the driver included in the offical > virtio-win iso builds, right..? > > Sooo, I'd like to try enabling MSI_SUPPORTED=1 in a test vioscsi.sys > build of my own, but before going down the WDK development rabbit whole, > I'd like to better understand why you've explicitly disabled this logic > within vioscsi.c code to start..? > > Is there anything that needs to be addressed / carried over from > virtio_stor.c in order to get MSI_SUPPORTED=1 to work with vioscsi.c > miniport code..? > > TIA! > > --nab > > -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
