From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <43E28EE8.3020103@domain.hid> Date: Thu, 02 Feb 2006 23:59:52 +0100 From: Philippe Gerum MIME-Version: 1.0 Subject: Re: [Xenomai-core] some results on my laptop References: <43E288AA.3050203@domain.hid> In-Reply-To: <43E288AA.3050203@domain.hid> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit List-Id: "Xenomai life and development \(bug reports, patches, discussions\)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jim Cromie Cc: xenomai@xenomai.org Hi Jim, Jim Cromie wrote: > > some random sucesses .. > > Ive been running an ipipe kernel as the default since shortly after 1/7. > Since then, Ive had a couple of freezes on boot, > and sometimes bash's auto-complete takes longer to complete, Eh? Maybe the CONFIG_PCI_MSI syndrom again? > but other than that, things have been solid. > > But that kernel wasnt configured using scripts/prepare-kernel.sh, > so was missing the xeno_* modules. > > RTS| -4814| -4583| -2582| 0| 00:02:00/00:02:00 > > > This was run on a pentium-M laptop, > with cpu-clock running at 600 MHz, (capable of 1.7 GHz) > I presume this might explain the negative latancies. > Im aware this is un-supported .. > The negative values are just there because even at 600Mhz, the timing anticipation applied by the nucleus to compensate for the intrinsic latency of the box is too high; i.e. the nucleus performs a bit too well latency-wise, so the anticipated timer ticks end up being a bit early on schedule. IOW, all is fine. Given the figures above, you could probably reduce the anticipation factor by setting the CONFIG_XENO_HW_SCHED_LATENCY (Machine menu) parameter to, say, 2500 nanoseconds (the default null value tells the nucleus to use the pre-calibrated value, which might be higher than this for your setup). Btw, I'm not sure if you enabled the local APIC in your kernel config; if you did not, you should: there is no reason to keep using the braindamage 8254 PIT when a LAPIC is available with your CPU. > The only thing that looks wrong is the test-duration. > I asked for 120 sec, it gave me 40 samples. > The test did take 120 to run. > You should disable the ACPI support if enabled, and especially everything related to the CPUfreq scaling and power suspend. -- Philippe.