Date: Thu, 4 Dec 2014 14:57:59 +0000 (GMT) From: Robert Watson <rwatson@FreeBSD.org> To: George Neville-Neil <gnn@neville-neil.com> Cc: Craig Rodrigues <rodrigc@FreeBSD.org>, FreeBSD Net <freebsd-net@freebsd.org>, "freebsd-virtualization@freebsd.org" <freebsd-virtualization@freebsd.org>, freebsd-arch <freebsd-arch@freebsd.org> Subject: Re: Enabling VIMAGE in GENERIC Message-ID: <alpine.BSF.2.11.1412041456190.87680@fledge.watson.org> In-Reply-To: <CAF05609-FCB4-4CB6-9533-A1F32A7F3F22@neville-neil.com> References: <CAG=rPVccq7R5%2Bcbm6nR1WCZDM=-xwwkmF=cw8PCuk58oHPA-gQ@mail.gmail.com> <1423616F-F44D-47E5-8595-DE862DC04464@bsdimp.com> <546A34C8.6060004@freebsd.org> <CAG=rPVeEEuK874g6%2BfVpHa5J_4V%2BA%2BQNbB5bCpXiS86jZW_U3Q@mail.gmail.com> <546C8812.2070904@FreeBSD.org> <20141119195923.GS24601@funkthat.com> <CAG=rPVdrjim_28ntxUv6qJxb-_bGhGabZipFyYzNuydZ2XPm5Q@mail.gmail.com> <69A8C06F-A7F6-49EC-8601-91AC4CDBFB13@FreeBSD.org> <547364EB.7090505@freebsd.org> <CAG=rPVeAM2_EEVYyhQiuXV7i%2Bpvw-uPYRBbjXeZhZKbrZzHRMg@mail.gmail.com> <547AEB93.3050600@freebsd.org> <CAF05609-FCB4-4CB6-9533-A1F32A7F3F22@neville-neil.com>
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On Mon, 1 Dec 2014, George Neville-Neil wrote: > On a slight tangent. I ran VIMAGE kernels vs. non VIMAGE kernels for both a > VANILLA kernel and a PF kernel (PF on but no rules) as a quick smoke test > today. The raw forwarding performance was unchanged between kernels with > and without VIMAGE on a 10G based system in the Sentex lab (lion1). I will > be doing a bit more work in this area and will then put up some results in > my netperf github repo. Was this a CPU-bound or network-bound workload? In general, I'd expect VIMAGE to have a modest overhead for most measurable workloads .. unless you are CPU-bound, in which case per-packet processing overheads might become (potentially) quite visible. They will also be more visible on simpler pipelines and with less cache-rich designs -- e.g., SoCs of various sorts. Doing a bit of CPU-bound networking on a modest ARM core might show off the effects better. Robert
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