Date: Tue, 20 Oct 2015 19:24:37 +1100 (EST) From: Ian Smith <smithi@nimnet.asn.au> To: Kevin Oberman <rkoberman@gmail.com> Cc: Luigi Rizzo <rizzo@iet.unipi.it>, "jfv@FreeBSD.org" <jfv@freebsd.org>, "ricera10@gmail.com" <ricera10@gmail.com>, "Eggert, Lars" <lars@netapp.com>, Giuseppe Lettieri <g.lettieri@iet.unipi.it>, "net@freebsd.org" <net@freebsd.org> Subject: Re: ixl 40G bad performance? Message-ID: <20151020190541.B15983@sola.nimnet.asn.au> In-Reply-To: <CAN6yY1uZJ5MhMdXLGy7REk8i6Z%2BjgJwMXFSu899%2BQwVaz%2BvP4w@mail.gmail.com> References: <79830D9D-94E6-47A9-92B9-D63DF5432272@netapp.com> <CA%2BhQ2%2Bj5PkmRWe-ydahExfvOj%2BzestFEn%2B5DZ9_acG2Z_v=8_w@mail.gmail.com> <C81B629B-67D5-4E5B-A215-452E837BE673@netapp.com> <CA%2BhQ2%2BiGk5Bx5mZ8v7K9cPdiNcJgBz99kmP8=twFnETw-bi2vw@mail.gmail.com> <CAN6yY1uZJ5MhMdXLGy7REk8i6Z%2BjgJwMXFSu899%2BQwVaz%2BvP4w@mail.gmail.com>
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On Mon, 19 Oct 2015 21:47:36 -0700, Kevin Oberman wrote: > > I suspect it might not touch the c states, but better check. The safest is > > disable them in the bios. > > > > To disable C-States: > sysctl dev.cpu.0.cx_lowest=C1 Actually, you want to set hw.acpi.cpu.cx_lowest=C1 instead. Otherwise you've only changed cpu.0; if you try it you should see that other CPUs will have retained their previous C-state setting - up to 9.3 at least. Setting performance_cx_lowest=C1 in rc.conf (and economy_cx_lowest=C1 on laptops) performs that by setting hw.acpi.cpu.cx_lowest on boot (and on every change to/from battery power) in power_profile via devd notifies. cheers, Ian
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