From mboxrd@z Thu Jan 1 00:00:00 1970 References: <9fd72e4545a6476983467f305b4d1a53@baumueller.com> From: Philippe Gerum Subject: Re: Where to start with Kernel config for Atom (64bit) Xenomai4 (evl) Date: Wed, 16 Mar 2022 16:01:30 +0100 In-reply-to: <9fd72e4545a6476983467f305b4d1a53@baumueller.com> Message-ID: <87wngtex6d.fsf@xenomai.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable List-Id: Discussions about the Xenomai project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Steub, Peter" Cc: xenomai@xenomai.org "Steub, Peter via Xenomai" writes: > Hi all, > > I like to get evl running on a quadcore Atom box. I started with a > standard ubuntu 20.04 installation Which will almost never work out of the box on x86. Some options commonly selected there will likely cause issues with any real-time infrastructure. > and build a kernel from ,v5.15.y-evl-rebase' branch with evl enabled and = things that ,evl check -file' told me disabled.=20 What do you mean? "evl check" is about verifying a configuration, not giving any runtime status. The output is a set of hints about kernel options that should appear as indicated in the submitted .config file, but do not. > Good news: the kernel runs and I do have a evl api. > Bad news: latmus tells me a worst jitter of 500=C2=B5s right away. You may want to check this [1] first. A common issue causing large latency peaks is with ACPI_PROCESSOR_IDLE as documented. > Also ,evl test' tells me: > *** stack smashing detected ***: terminated > Aborted (core dumped) > ** poll-multiple: BROKEN # gdb /usr/evl/tests/poll-multiple may help, running it then asking for a backtrace when it breaks. I could have a look at the backtrace output to figure out what happens, since I cannot reproduce this on any of my fixtures ATM, so this may depend on a glibc setup. > > I have a Xenomai3 setup on this same machine that has a 30=C2=B5s jitter.= =20 > You should expect the same from EVL/x4, a bit better than x3 under SMP stress due to the improved locking model. > On the evlproject.org site there is a list of ports including a x86_64 > atom with all the boxes checked. Is there anywhere more information > about these ports, are the .config files somewhere to be found, to be > used as a starting point? In short, no. But the document at [1] helps in removing known issues from stock kernel configurations. > I'm also interested in the Raspberry PI > port, but I don't like to try it all out again for myself, a > kernel-config or in case of the PI even a binary or a hole Image would > be great! Which PI? All PI kernels can be built using the default mainline config for the architecture at hand. This is actually the ones I'm using. e.g. ARCH=3Darm64 defconfig for PI3/64bit and PI4/64bit, or multi_v7_defconfig for 32bit (including PI0 and PI2). > Also I'm kind of lost on documentation, all I find leads back to the > evlproject.org main site. Everything related to EVL and xenomai4 is hosted at evlproject.org ATM. > Where can I find what to do if say "poll-multible" failed? I have the fee= ling I am still missing a big junk of documentation! Can anyone please poin= t me at it! > This means a non-reg test fails, so either the test code itself is broken, or something it exercises is broken. In this case, #1 is most likely given the error report. What you can do is to help in understanding why this breaks: see above regarding the gdb command. > Thank you > > Peter Steub [1] https://evlproject.org/core/caveat/ --=20 Philippe.