From mboxrd@z Thu Jan 1 00:00:00 1970 From: keith.busch@intel.com (Keith Busch) Date: Fri, 17 Mar 2017 18:28:44 -0400 Subject: [PATCH v4 RFC] nvme: improve performance for virtual NVMe devices In-Reply-To: <1489787099-2049-1-git-send-email-helen.koike@collabora.com> References: <1489787099-2049-1-git-send-email-helen.koike@collabora.com> Message-ID: <20170317222843.GD13709@localhost.localdomain> On Fri, Mar 17, 2017@06:44:59PM -0300, Helen Koike wrote: > diff --git a/drivers/nvme/host/Kconfig b/drivers/nvme/host/Kconfig > index 90745a6..7ada6f3 100644 > --- a/drivers/nvme/host/Kconfig > +++ b/drivers/nvme/host/Kconfig > @@ -59,4 +59,13 @@ config NVME_FC > To configure a NVMe over Fabrics controller use the nvme-cli tool > from https://github.com/linux-nvme/nvme-cli. > > +config NVME_DBBUF > + bool "NVM Express Doorbell Buffer Config Command" > + depends on NVME_CORE > + ---help--- > + This provides support for the Doorbell Buffer Config Command, which > + reduces the number of required MMIOs to ring doorbells, improving > + performance for virtualised environments where MMIO causes a high > + overhead. > + > If unsure, say N. It looks like you took the last line from NVME_FC's help. But I don't think this capabilty should enabled through kernel config, though. Just have the driver react based on the device's advertised capabilities, ya?