Date: Mon, 13 Sep 2010 15:21:13 -0700 From: "David Christensen" <davidch@broadcom.com> To: "pyunyh@gmail.com" <pyunyh@gmail.com>, "Andre Oppermann" <andre@freebsd.org> Cc: Tom Judge <tom@tomjudge.com>, "freebsd-net@freebsd.org" <freebsd-net@freebsd.org>, "yongari@freebsd.org" <yongari@freebsd.org> Subject: RE: bce(4) - com_no_buffers (Again) Message-ID: <5D267A3F22FD854F8F48B3D2B52381933B540B4C14@IRVEXCHCCR01.corp.ad.broadcom.com> In-Reply-To: <20100913193947.GH1229@michelle.cdnetworks.com> References: <4C894A76.5040200@tomjudge.com> <20100910002439.GO7203@michelle.cdnetworks.com> <4C8E3D79.6090102@tomjudge.com> <20100913184833.GF1229@michelle.cdnetworks.com> <4C8E775D.8070202@freebsd.org> <20100913193947.GH1229@michelle.cdnetworks.com>
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> I'm under the impression the header splitting in bce(4) is for > LRO(opposite of TSO), not for VM magic to enable page flipping > tricks. Header splitting was implemented in the Linux version of bce(4) to prevent jumbo memory allocations. Allocating 9KB frames was causing problems on systems used for virtualization. (Harder to find a contiguous 9KB frame when a hypervisor is in use.) Using 4KB or smaller buffer sizes was considered more compatible with virtualization. LRO (Large Receive Offload, aka Transparent Packet Aggregation or TPA on the 10Gb controllers) is not supported on the 1Gb bce(4) devices. Davehome | help
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