From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <4E5B3C2C.7000503@domain.hid> Date: Mon, 29 Aug 2011 09:13:48 +0200 From: Gilles Chanteperdrix MIME-Version: 1.0 References: In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Subject: Re: [Xenomai-help] milli-second overruns under heavy load on x86, running Xenomai 2.5.6 List-Id: Help regarding installation and common use of Xenomai List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: George Broz Cc: xenomai@xenomai.org On 08/26/2011 11:49 PM, George Broz wrote: >> Gilles Chanteperdrix wrote on > 08/26/2011 02:18:05 PM: >> On 08/26/2011 10:42 PM, George Broz wrote: >>> Hello, >>> >>> I'm experiencing very large overruns in the neighborhood of 10 to 50 >>> *milli-seconds* as reported by the Xenomai latency tool in user-task > mode >>> whenever the Linux OS is heavily loaded. Under lighter loads these are > in >>> the 30 to 70 micro-second (normal) range. >>> >>> My system is: >>> - Linux 2.6.37.6 (32-bit), Ubuntu 10.10 distribution >>> - Xenomai 2.5.6 using I-pipe patch adeos-ipipe-2.6.37.6-x86-2.9-02 >>> - Intel x86 Atom (dual-core) CPU D510 @ 1.66GHz >>> - Emb. dev board from Intel (ICH8M ctrlr, Ethernet h/w for e1000e) >>> - Xenomai configured w&w/o --enable-smp --enable-x86-tsc options >>> - gcc version 4.4.5 >>> >>> I've followed all of the recommendations for kernel configuration and > have >>> disabled CPU sleep features in the BIOS such as SpeedStep and > C-States. >>> Legacy USB has been disabled in the BIOS. Hyperthreading has also been > >>> disabled, although I don't think it matters. >> >> Have you tried to enable the SMI workaround? >> >> -- >> Gilles. >> > > Yes - SMI workaround was enabled when the overruns were observed. Could you try disabling CONFIG_SMP to see if you get the same behaviour, and take a few traces? If you processor supports 64 bits mode, could you try running a 64 bits kernel? -- Gilles.