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From r..@hyperreal.org
Subject cvs commit: apache-apr/pthreads README.rse
Date Thu, 12 Aug 1999 07:31:02 GMT
rse         99/08/12 00:31:02

  Added:       pthreads README.rse
  Log:
  Ralf's latest writeup: ``Get the Apache/pthread beast running''.  Those who
  had great problems to get Apache/pthread running in the past (especially on
  non-Linux and non-AIX platforms ;) can now give it another try by following
  the ``FooBar/OS + Pth'' instructions in this document. With this variant
  Apache/pthread can be used to get a multithreaded Apache running on mostly all
  current Unix flavors, I think.
  
  Revision  Changes    Path
  1.1                  apache-apr/pthreads/README.rse
  
  Index: README.rse
  ===================================================================
  
    Get the Apache/pthread beast running
    Ralf S. Engelschall, 12-Aug-1999
    ------------------------------------
  
    These are my instructions for getting Apache/pthread running under various
    platforms (mainly FreeBSD for now). One usually has to fight against two
    major problems:
  
    1. Apache/pthread (as Apache 1.3) uses an inter-process lockfile 
       for optionally serializing accepts. This means that usually either
       flock(2) or fcntl(2) is used. The problem is that in a multi-threaded
       environment this works only by coincidence (usually when threads are
       implemented in kernel-space).  For mostly all user-space implementations
       this will cause Apache/pthread to hang on connections (actually in the
       middle of processing the request in case the request processing thread
       had to be suspended once because of a blocking situation).
  
       There are two solutions: If the user-space threading library supports
       inter-process mutexes (_POSIX_THREAD_PROCESS_SHARED is defined) one can
       use pthread_mutex_t inside a shared memory segment. But AFAIK there is
       still no freely available user-space pthread library which supports this
       (the forthcoming GNU Pth versions will support this, but the stuff is
       still not released).  So the only possibility is to use no accept
       serialization at all. The effect can be that the server is slower because
       of contention on the accept socket.
  
    2. Apache/pthread uses poll(2) which is not available on all platforms.
       There is just one solution: Emulate poll(2) with select(2) For this one
       can use my poll emulation library which I've comitted to the
       apache-apr/poll/ repository area.
  
    3. Portable user-space threading environments like GNU Pth cannot
       easily provide system call wrappers, because there is no 100% portable
       way to provide this "magically". For instance Pth instead provides two
       variants: soft syscall wrapping via ``#define <syscall>
       _pthread_<syscall>'' in pthread.h and hard syscall wrapping with
       syscall(2). The soft syscall wrapping is 100% portable, but requires an
       #include <pthread.h> in _EVERY_ source file of the application which uses
       a to be wrapped system call, of course. The hard system call wrapping
       works "magically" just at the linker phase, but has some portability
       problems. The best solution is to use soft system call wrapping by just
       including pthread.h in every Apache source file.
  
    And here are the success stories for pariticular OS+Pthread variants:
  
    o  FreeBSD 3.1 + John Birrell' uthread
  
       - uthread is a user-space pthread library in FreeBSD's libc_r
         which contains both thread-safe libc functions and the thread
         functions. This library replaces libc for threaded applications.  For
         older FreeBSD versions (2.2.x) one has to build libc_r manually as part
         of a 'make world'.
       
       - uthread is a plain user-space implementation and this way the
         inter-process accept lock file cannot be used (it suspends the whole
         process and not just the current thread). One has to make sure that no
         USE_XXX_SERIALIZED_ACCEPT is defined for FreeBSD in
         src/include/ap_config.h. For this a -DNO_SERIALIZED_ACCEPT can be used.
  
       - FreeBSD <= 3.2-STABLE lacks poll(2) in libc_r, altough poll(2) exists
         in libc since FreeBSD 3.0. One has to use the poll emulation library.
  
       Follow these steps:
  
       $ cd <ROOT>/apache-apr/poll
       $ ./configure 
       $ make
  
       $ cd <ROOT>/apache-apr/pthread
       $ CC='cc' \
         OPTIM='-O2' \
         CFLAGS='-pthread -I\$(SRCDIR)/../../poll -DNO_SERIALIZED_ACCEPT' \
         LDFLAGS='-pthread -L\$(SRCDIR)/../../poll' \
         LIBS='-lpoll' \
         ./configure \
         --with-layout=GNU \
         --target=apache \
         --prefix=/tmp/apache-pthread \
       $ make 
       $ make install
  
    o  FooBar/OS + Ralf S. Engelschall's GNU Pth
  
       - Pth is also a user-space pthread library and this way the inter-process
         accept lock file cannot be used (it suspends the whole process and not
         just the current thread). One has to make sure that no
         USE_XXX_SERIALIZED_ACCEPT is defined for FreeBSD in
         src/include/ap_config.h.  For this a -DNO_SERIALIZED_ACCEPT can be
         used.
  
       - FooBar/OS often lacks poll(2), but this is no problem, because GNU Pth
         on every platforms provides its own poll(2) emulation (based on
         select(2) which the Pth event manager uses internally). So you don't
         have to worry about this.
  
       Follow these steps:
  
       $ cd <ROOT>/apache-apr
       $ lynx ftp://alpha.gnu.org/gnu/pth/pth-1.1b3.tar.gz
         [You can use also any later Pth version, of course.                  ]
         [Especially release versions >= 1.1.0 from ftp://ftp.gnu.org/gnu/pth/]
       $ gunzip <pth-1.1b3.tar.gz | tar xvf -
       $ cd pth-1.1b3
       $ ./configure \
          --disable-shared \
          --enable-pthread \
          --enable-syscall-soft
       $ make
       $ make test
  
       $ cd <ROOT>/apache-apr/pthread
       $ CC='cc' \
         OPTIM='-O2' \
         CFLAGS='-I\$(SRCDIR)/../pth-1.1b3 -DPTHREAD_EVERYWHERE -DNO_SERIALIZED_ACCEPT' \
         LDFLAGS='-L\$(SRCDIR)/../pth-1.1b3/.libs' \
         LIBS="-lpthread" \
         ./configure \
         --with-layout=GNU \
         --target=apache \
         --prefix=/tmp/apache-pthread
       $ make
       $ make install
  
  
  
  

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