Date: Mon, 12 Mar 2012 21:33:07 +0200 From: Ivan Klymenko <fidaj@ukr.net> To: Alexander Motin <mav@FreeBSD.org> Cc: freebsd-performance@FreeBSD.org, FreeBSD current <freebsd-current@freebsd.org> Subject: Re: Improved Intel Turbo Boost status/control Message-ID: <20120312213307.2be6bdf9@nonamehost.> In-Reply-To: <4F5E4B57.1050605@FreeBSD.org> References: <4F5E4B57.1050605@FreeBSD.org>
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=D0=92 Mon, 12 Mar 2012 21:15:35 +0200 Alexander Motin <mav@FreeBSD.org> =D0=BF=D0=B8=D1=88=D0=B5=D1=82: > Hi. >=20 > I'd like to note that recent r232793 change to cpufreq(4) in HEAD > opened simple access to the Intel Turbo Boost status/control. I've > found that at least two of my desktop systems (based Nehalem and > SandyBridge Core i7s) with enabled Intel Turbo Boost in BIOS it is > not use it by default, unless powerd is enabled. And before this > change it was difficult to detect/fix. >=20 > ACPI reports extra performance level with frequency 1MHz above the=20 > nominal to control Intel Turbo Boost operation. It is not a bug, but=20 > feature: > dev.cpu.0.freq_levels: 2934/106000 2933/95000 2800/82000 ... > In this case value 2933 means 2.93GHz, but 2934 means 3.2-3.6GHz. >=20 > After boot with default settings I see: > dev.cpu.0.freq: 2933 > , that means Turbo Boost is disabled. >=20 > Enabling powerd or just adding to rc.conf > performance_cpu_freq=3D"HIGH" > enables Turbo Boost and adds extra 10-20% to the system performance. >=20 > Turbo Boost operation can be monitored in run-time via the PMC with=20 > command that prints number or really executed cycles per CPU core: > pmcstat -s unhalted-core-cycles -w 1 >=20 Thank you very much! performance_cpu_freq=3D"HIGH" and as this option must be combined with state of the processor C1 C2 C3? performance_cx_lowest=3D"XX" economy_cx_lowest=3D"XX"
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