From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <43904AE7.4090002@domain.hid> Date: Fri, 02 Dec 2005 14:23:51 +0100 From: Philippe Gerum MIME-Version: 1.0 Subject: Re: [Xenomai-help] i386 2.4 backport performing (too?) well References: 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: > With the arrival of the 2.4 i386 adeos ipipe patch for xenomai [1], I > decided to try to compile xenomai-trunk for a 2.4 kernel. This worked > flawlessly, and moreover, I got excellent latency results: > > I used the "same" kernel config as for our 2.4.31 rtai3.0r5 kernel, > which is based on Takis Issaris' liveCD config. > > This resulted in a maximal latency of 30 usec after a run of over 100 > minutes under heavy load (tar and dd loops, compiling, keyboard > interrupts and ping flood) [2]. > > 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? > > This seems too good to be true? Can one simply compare the results of > the former RTAI lxrt-latency test with the xenomai latency test? > > Klaas > > [1] > [2] HW: a via mini-itx board, > HW config at > > > _______________________________________________ > Xenomai-help mailing list > Xenomai-help@domain.hid > https://mail.gna.org/listinfo/xenomai-help > -- Philippe.