From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <439411B5.7030708@domain.hid> Date: Mon, 05 Dec 2005 11:08:53 +0100 From: Philippe Gerum MIME-Version: 1.0 Subject: Re: [Xenomai-help] i386 2.4 backport performing (too?) well References: <43904AE7.4090002@domain.hid> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit List-Id: Help regarding installation and common use of Xenomai List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Klaas Gadeyne Cc: xenomai@xenomai.org Klaas Gadeyne wrote: > On Fri, 2 Dec 2005, Philippe Gerum wrote: > >> Klaas Gadeyne wrote: > > [...] > >>> For comparison, on the same hardware platform: - the RTAI >>> lxrt-latency on rtai 3.0r5 (adeos oldgen r18c1 >>> patch for 2.4.31 also) test reports 38 usec >>> - the latency test of xenomai 2.01 running on a 2.6.14-ipipe-1.0-10 >>> kernel resulted in a latency of 80 usec. >> >> >> 80 us on 2.6 is clearly pathological if 2.4 gives 30 us. All tests >> using 2.6.14-1.0-10 on dual SMP 750Mhz and 2.8Ghz, Geode 266 Mhz, >> Celeron 1Ghz, Centrino 1.6 Mhz and Pentium 90Mhz show a slight >> advantage for 2.4 over 2.6 (1-3%), but still in the error margin, I >> think. Maybe some option is enabled in your 2.6 configuration that >> might trigger this very high value? > > > I rechecked the 2.6 config. Apart from the lapic option, which I > couldn't enable with xenomai [*], I can't see something obvious that I > would have missed. I'm sending you the config file in private. > > Note that I haven't tested the 2.6 kernel with xenomai-trunk yet though... > > thx, > > Klaas > > [*] When enabling local apic in the kernel configuration and booting > with the lapic option, I get > > Disable APIC support or pass "lapic" as boot param. > lapic=1 on your boot line. This is not a Xeno issue, but a Linux kernel requirement. Using the local APIC is even recommended when available on your hw with Xeno. > while loading xeno_hal. > > > -- Philippe.