glibc_with_ptt

linux下的多线程调试工具

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                  Building glibc with both traditional NPTL
                          and NPTL with PTT support

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This document is intended for Linux distribution maintainers who would like
to provide PTT to their users. It explains how to build the glibc with both
traditional NPTL and instrumented NPTL for PTT support.

  1) PTT patch for glibc
  2) Glibc building options
  3) Guidelines for building glibc with PTT support
  4) Building PTT with a friendly system glibc

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  1) PTT patch for glibc
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PTT comes with 3 patches for glibc version 2.3.4 to 2.3.6 and an experimental
patch for glibc 2.4. These patches include:

- trace points inserted into NPTL routines.
- PTT module files that define functions used to collect trace point data.
- additionnal options in glibc configuration files (configure.in, configure,
  config.h.in, config.make.in).
- a modified nptl/Makefile.

All things added in NPTL code are enclosed in preprocessor directives:

- trace points are enclosed in:
    #ifdef PTT_LIBPTHREAD
            /* trace point instruction */
    #endif /* PTT_LIBPTHREAD */

- new files are enclosed in:
    #ifdef PTT_NEW_FILES
            /* new file code */
    #endif /* PTT_NEW_FILES */

PTT patches can be applied like this:
$ cat ptt_glibc-2.x.x.patch | patch -d $GLIBC_SRC -p1

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  2) Glibc building options
==============================================================================

Once the PTT patch has been applied to the glibc, you can build the glibc in
three different ways:

- if nothing special is done, the above macros (PTT_LIBPTHREAD and
  PTT_NEW_FILES are not defined), thus original glibc is built.

- using --with-ptt in the glibc ./configure script defines PTT_LIBPTHREAD and
  PTT_NEW_FILES, thus glibc is built with PTT support. Of course, NPTL must be
  enabled (--with-tls).
  Modified files are those which match libpthread* (mainly
  libpthread-2.x.x.so).

- using --with-ptt and --with-ptt-trace-info in the glibc ./configure script
  builds glibc with PTT support and trace points for PTT internals. This
  should be useful only for PTT developpers.

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  3) Guidelines for building glibc with PTT support
==============================================================================

If you plan to build a glibc with PTT support, you should follow the following
steps (patch_glibc/install_glibc.sh does the same):

1. Patch the glibc:
   $ cat ptt_glibc-2.x.x.patch | patch -d $GLIBC_SRC -p1

2. Build glibc with --with-ptt option.

3. Rename libpthread-2.x.x.so in libptread_ptt-2.x.x.so and create a symbolic
   link libpthread_ptt.so.0 -> lipthread_ptt-2.x.x.so.

4. Build glibc without --with-ptt option (traditional build). Libraries
   created in step 2 will be overrided by traditional libraries.

You now have a traditional glibc lib directory with 2 new elements:
- the instrumented NPTL libpthread_ptt-2.x.x.so
- a link to this library libpthread_ptt.so.0

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  4) Building PTT with a friendly system glibc
==============================================================================

PTT can now be built without running patch/install_glibc.sh before. You just
have to run the ./configure script with the --with-ptt-friendly-glibc option.
This option assumes that the system glibc has support for PTT (that is to
say, includes libpthread_ptt-2.x.x.so and libpthread_ptt.so.0).

Assuming that $LIB is the system directory where libpthreads are installed
(generally /lib), PTT is built with the following commands:

$ cd $PTT
$ ./configure --prefix=$INSTALL --with-friendly-ptt-glibc=$LIB
$ make
$ make install