From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Mon, 03 Oct 2011 10:39:14 +0200 From: "Petr Cervenka" References: <20110926090226.9C75AD68@domain.hid> In-Reply-To: <20110926090226.9C75AD68@domain.hid> MIME-Version: 1.0 Message-Id: <20111003103914.8A2B636C@centrum.cz> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Subject: Re: [Xenomai-help] Frequency downscaling of new intel CPU List-Id: Help regarding installation and common use of Xenomai List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: xenomai-help Hello again. I know, that my problem is not so close related with the xenomai. But I t= hink many of xenomai users with new intel CPUs have similar problem. I tried it it with two different main boards and none of the BIOS setting= s helped. (C-states: disabled, Speedstep: disabled, CPU idle: high perfor= mance, TurboBoost: disabled, ...). My theory is that the linux kernel ove= rrides BIOS settings, but I don't know how to prove it. Any ideas that could help me? Petr Cervenka ______________________________________________________________. > Od: "Petr Cervenka" > Komu: "xenomai-help" > Datum: 26.09.2011 09:02 > P=C5=99edm=C4=9Bt: Frequency downscaling of new intel CPU > >Hello. > >I recently tried newer computer and I suprusingly realized that it has b= igger load than the old one with our xenomai application. >The problem is in the frequency downscaling of the processor when the lo= ad in under 100%. >Of course I have disabled CPU_FREQ, ACPI_PROCESSOR and INTEL_IDLE as sug= gested. >Later I tried also to disable CPU_IDLE, 7300_IDLE (intel chipset idle me= mory) and all power efficiency settings in the BIOS, but without success. >The experienced behaviour is following: >when the process is waiting for an event, the processor lowers its frequ= ency and when the event happens it tries to restore (slowly) its nominal = frequency. > >Do you have any advice or tip what to try, because I'm really desperate? > >Best regards > >Petr Cervenka > >configuration: >Xeon E3-1220 (Sandy Bridge) >linux-2.6.38.8 >xenomai-2.5.6 >