Friday Jun 19, 2009

EventMachine and the elusive emptys

Having built Ruby 1.9 packages for Solaris Nevada we had to try installing the commonly used gems, particularly those for the Rails stack and specifically the ones we use with the Apache Olio Rails app. One of these was eventmachine which is used by Thin and which is a great piece of Software. It installed fine on our Solaris Nevada b116 x64 box but failed to install on our Nevada b116 SPARC box. The error was pretty bizarre too:

usr/ccs/bin/as: error: no input filename given
usage: /usr/ccs/bin/as [-V] [-Q{y,n}] [-q] [-s]
        [-S] [-K {pic,PIC}] [-o objfile] [-L] [-T]
        [-P [[-Yc,path] [-Ipath] [-Dname] [-Dname=def] [-Uname]]...]
        [-m [-Ym,path]] [-n] [-ul] [-xF]
        [-m32] [-m64]
        [-xarch={v7,v8,v8a,v8plus,v8plusa,v8plusb,v9,v9a,v9b,sparc,sparcvis, sparcvis2,sparcfmaf,sparcima}]
        [-xcode={pic13,pic32}] file.s...
\*\*\* Error code 1
make: Fatal error: Command failed for target `binder.o'

What looked suspicious here, was the build line, which looked like this:

g++ -I. -I/usr/ruby/1.9/include/ruby-1.9.1/sparc-solaris2.11 -I/usr/ruby/1.9/include/ruby-1.9.1/ruby/backward -I/usr/ruby/1.9/include/ruby-1.9.1 -I/var/ruby/1.9/gem_home/gems/eventmachine-0.12.8/ext -DBUILD_FOR_RUBY -DHAVE_RB_THREAD_BLOCKING_REGION -DHAVE_TBR -DHAVE_WRITEV -DHAVE_WRITEV -DOS_UNIX -DOS_SOLARIS8 -DWITH_SSL -I/usr/sfw/include -fPIC -g -O3 -fPIC  -g -obinder.o -c binder.cpp

There's no space in '-obinder.o' which you'd normally expect to read '-o binder.o'. It looked odd, though it's not unusual for spaces to be ommited when passing names to options, I'd just never seen it on a build line before so it stood out. Looking at the output with -v set as one of the flags passed to g++, gave more data but not anything useful. We looked at it on the x64 system (again with -v as a flag to g++) and it went through the same steps but didn't fail.  But it did use a different assembler! gcc/g++ on x64 uses /usr/sfw/bin/gas but on sparc uses /usr/ccs/bin/as. It also became apparent by running the assembler manually that it was choking on -obinder.o, it seems that gas is more tolerant than as :o(

The Makefile that gets generated by extconf.rb when you install the gem has lines in it's .SUFFIXES section of the form:

        $(CXX) $(INCFLAGS) $(CPPFLAGS) $(CXXFLAGS) $(COUTFLAG)$@ -c $<

and earlier in the file COUTFLAG is defined as:


Which ultimately results in -obindir.o (same for all of the other objects it builds).

Matz seems to have hit this problem before, because the Ruby 1.9.1 Makefile contains a fix for a similar problem in Ruby (although it still happens when building the ext/\*.c sources)

empty =
OUTFLAG = -o $(empty)
COUTFLAG = -o $(empty)

Which results in a space being inserted after the '-o' for $(OUTFLAG) and for $(COUTFLAG)


The Makefile is of course generated by extconf.rb which gets it's instructions on how to create the Makefile from mkmf.rb which Ruby provides. So the fix would be to make the changes outlined above in lib/ruby/1.9.1/mkmf.rb or to have it create the SUFFIXES lines with a space between the COUTFLAG variable and the output file name. We can do that for any packages that we build, but we also need to raise a bug with Ruby.

Monday Mar 23, 2009

Building eventmachine on OpenSolaris and Solaris Nevada

If you are installing the eventmachine Ruby Gem on OpenSolaris (which you do whenever you install Thin). Make sure that you use GNU 'make' and not Solaris 'make' otherwise the installation will fail. You can do this by making sure that you have the SUNWgmake package installed and that /usr/gnu/bin is in your PATH and is before /usr/bin and/or /usr/ccs/bin

GNU 'make' implicitly sets the CXX variable used in the eventmachine Makefile to 'g++' and as g++ is in /usr/bin (assuming you have the SUNWgcc package installed)  you don't have to set it yourself. eventmachine will build with the Solaris version of 'make' but you would need to set CXX manually before installing the gem, i.e.:

CXX=/usr/sfw/bin/g++ gem install eventmachine

On Solaris Nevada Distributions (SXCE) GNU make is only available as 'gmake' and so by default eventmachine will use /usr/bin/make which is the Solaris make. In that case you need to set CXX as described above.

Remember: four is the number of Make commands available on OpenSolaris and the number of Make commands available on OpenSolaris is four, no more no less.

Monday Feb 16, 2009

Thin on OpenSolaris

Since the start of the year we've been testing with the Apache Olio Rails application on OpenSolaris. Early on we found that when using Thin as our Rails runtime, every now and then a Thin instance would abort and core dump after an assertion failure in EventMachine. This really only happened under high loads and was hard to recreate. The problem is detailed here:

We talked to the EventMachine folks on the eventmachine-talk alias and after a couple of days they were able to come up with a fix that we then tested at length. The fix is now available in EventMachine 0.12.4 . The support that they gave us was really fantastic and helped us resolve a problem that really threatened to hold up our project. Thanks particularly to Aman Gupta.

So if you are using or planning on using Thin and EventMachine on OpenSolaris, EventMachine 0.12.4 is the way to go.


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