Re: [Discuss-gnuradio] Cross compile GNURadio on ARM in Odroid XU3

[Dennis Glatting]

Yep.

In my case it's a research project that will be taken into the field
(there will be three different embedded boards). Cross compiling in the
field isn't reasonable. I have an external USB disk (a SHD) to hold
source, objs, and swap, thereby lowering uSD writes; plus I need to
stress the USB interface, which has uncovered an ugly problem (yea! More
debug).

My primary development is an x86 environment (8-cores at 4.7-5GHz,
liquid cooled). Getting OpenMP to work when cross compiled was a dismal
failure but the native compiler and libraries worked. It's likely  my
cross environment was total crap.

As you mentioned, all those CFLAG settings and little source touches
required days of work and pots of coffee. I don't recommend it as a form
of entertainment.


On Wed, 2015-07-08 at 10:45 -0400, West, Nathan wrote:
> The conflicting advice here is part of the problem here. All, I really
> wish we could stop providing conflicting advice to people that come
> asking for help on embedded builds. Native compile is not even an
> option if you plan to do actual development. Cross compile is
> difficult the first few times and may not be necessary.
> 
> 
> Shaun, I'm going to dump a lot of text here that will hopefully guide
> you down a single path rather than receiving disparate information
> since I know you've been trying to get this working for a while.
> 
> 
> Philip, and others interested in embedded workflows (embedded WG?): I
> suspect we need to rework the message on the embedded page to include
> people that have simpler ARM requirements. What follows is my first
> attempt at exposing a small collection of options that I think should
> be apparent on the embedded wiki.
> 
> 
> Assuming the actual goal is to get GNU Radio + some flowgraph running
> on an ARM processor there are multiple ways to reach this point. The
> first step in all of them is to build GNU Radio with an ARM target.
> Here are the three best approaches:
>   * native compile where the target processor does the work
>   * cross compile where a different (probably x86_64) processor does
> all of the work
>   * use a package manager to install a binary
> 
> 
> Following is a short list of some highlights of each method:
> 
> 
> *** Cross compile
>    ** Pros
>      * Compilation is faster
>      * development happens in your normal environment
>    ** Cons
>      * Hard to get bootstrapped (need an SDK that targets your OS +
> all dependencies)
> *** Native compile
>    ** Pros
>      * intuitive as long as your embedded image comes with a C
> compiler and python
>    ** Cons
>      * Compilation is very slow. Even on more capable quad core 2GHz+
> ARMs an x86_64 cross build will still be much faster
>      * Usually low memory. The infamous out of memory manager will
> subtly kill your compiler, especially on swig
> *** Package manager binary install
>    ** Pros
>      * Fastest way to get GNU Radio
>    ** Cons
>      * Stuck with whatever version is packaged for you
> 
> 
> 
> 
> The route you take really depends on your needs. If you just need GNU
> Radio and you're tinkering with some flowgraphs then by all means use
> a binary install if it is available for your machine. If a binary
> isn't available then you need to compile from source. If you know
> you're only going to need to do this once then a native compile is
> acceptable, but you need to be aware of the trade offs you are making.
> You can get around the low memory problem by using SWAP which comes
> with its own problems (SD card wear out and its slower). If you expect
> to be doing any development on GNU Radio or an OOT module you are
> working on then it is probably worth the investment in getting
> bootstrapped with a cross compiler environment.
> 
> 
> ** Native compile
> 
> 
> The native compile is mostly the same as doing a native compiler on
> x86_64. The primary difference is that it is harder for us to detect
> ARM features at configure time. The practical implication is that you
> need to provide some assistance to VOLK through cmake. This is where
> the CFLAGS and CXXFLAGS command line comes in. I honestly hate seeing
> people dump versions of their CFLAGS as if it were an authoritative
> source because this is the kind of thing that really needs to be
> determined by whoever is doing the build. The fact is you can't get
> away without knowing your -march settings on ARM. Once you get cmake
> working, make and make install away.
> 
> 
> ** Cross compile
> 
> 
> Again there are several options. The core GNU Radio developers have a
> preference for using Open Embedded (OE) based systems and Tom provides
> a rootfs and SDK. Philip maintains the layers that provide GNU Radio
> support. If your board is supported by an OE layer then you can learn
> more about using OE on their website. It's a pretty nice tool. If your
> board is not supported by OE you can either: 1) add support
> (non-trivial for first timers), 2) use Tom's rootfs and chroot (I find
> this awkward, but some people like it), 3) use another method. If you
> want to cross compile GNU Radio with OE we have instructions on the
> wiki (source the OE SDK environment, point cmake at oe-sdk.cmake
> toolchain file, make && make install)
> 
> 
> If you don't want to use OE there are still options. You may be able
> to get an SDK for your distribution. There's an unknown amount of work
> ahead of your with this route because of all of the GNU Radio
> dependencies. If the SDK does not include a dependency then you must
> build it. If you're inexperienced with this then I will let you in on
> a secret: GNU Radio is actually really easy to cross compile compared
> to many of our dependencies.
> 
> 
> Finally there are hybrid solutions that I have heard of working that
> involve using distcc where the ARM dispatches work to a distcc node
> running on an x86_64 processor. I've never done this and don't have
> anything else to say about it.
> 
> 
> ** Conclusion
> 
> 
> There is no one way to get GNU Radio on an ARM. The method you take
> depends on  your needs and is a decision no one else can make for you.
> When people come to the list asking for a native compile on ARM we
> should stop telling them they have to cross compile. Similarly when
> people come to the list asking for a cross compile we need to stop
> telling them they should do a native compile.
> 
> 
> Sorry this is long, but I think some edited form of it will be useful
> for the wiki.
> 
> 
> Shaun, if you pick a route I think we can guide you towards a solution
> that works for you. 
> 
> 
> Cheers,
> Nathan
> 
> 
> 
> 
> 
> On Wed, Jul 8, 2015 at 9:56 AM, <address@hidden> wrote:
>         I should also point out that ARCH already has up-to-date Gnu
>         Radio, UHD, and friends for ARM.
>         
>         I run it on my XU3 and U3 platforms.
>         
>          
>         
>          
>         
>          
>         On 2015-07-08 01:22, Dennis Glatting wrote:
>         
>         > On Tue, 2015-07-07 at 21:14 -0700, shaunwang wrote:
>         > > Hello everyone I need help on how to successfully cross
>         > > compile GNURadio on ARM processor in Odroid XU3. I have
>         > > read many websites in official GNURadio websites. like the
>         > > following ones
>         > > 
> https://gnuradio.org/redmine/projects/gnuradio/wiki/Cross_compile_GNU_Radio_and_install_on_target
>  https://gnuradio.org/redmine/projects/gnuradio/wiki/OE_PyBOMBS They don't 
> have enough steps for me to finish cross compile. the big drawback is that 
> they keep directing me to read other things, and then I lost. I wish someone 
> can give me more specific instruction on how to do this. Thank you a lot.
>         > Where are you stuck?
>         > 
>         > I am native compiling on ARM under a flavor of Ubuntu. I found a
>         > combination of binary and source was key. Some of the binary 
> packages
>         > are old so the pain of source was a necessary approach for those
>         > packages. Pybombs was useful but limited. I had to customize some 
> cmake
>         > files.
>         > 
>         > One of the problems under ARM/Ubuntu is the system libraries are 
> /not/
>         > found in expected places. This was also true of some includes.
>         > Installing (i.e., from source) wx was painful and I had to hack a 
> header
>         > file, IIRC. 
>         > 
>         > Getting NEON for VOLK to compile /and/ work was a bit painful. One 
> I had
>         > VOLK/Arm working help from this list solved one of remaining three
>         > problems. The other two were non-problems.
>         > 
>         > I have an intensive graph running for three days. There's a problem 
> with
>         > one of my SDRs but it is also a problem on x86 -- debugging to do.
>         > Otherwise, GNURadio/head works.
>         > > Shaun -- View this message in context:
>         > > 
> http://gnuradio.4.n7.nabble.com/Cross-compile-GNURadio-on-ARM-in-Odroid-XU3-tp54685.html
>  Sent from the GnuRadio mailing list archive at Nabble.com. 
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