[lttng-dev] [RELEASE] Babeltrace 2.0.0-pre1

[Nathan Lynch]

Jérémie Galarneau <jeremie.galarneau at efficios.com> writes:
> Known limitations
> -----------------
>
> Being a "pre" release, a number of features are still in active development and
> bugs are being worked on.
>
> This first release does not expose the Python packages (present in the Git tree)
> as we are reworking them to accomodate the latest round of API changes.
>
> * The "--stream-intersection" mode is not available.
> * Traces without their packet context field type's `timestamp_begin` and
>   `timestamp_end` fields mapped to a clock class fail to be read
>   (traces produced by old versions of LTTng and CTF Writer).
> * The man page has not been updated to match the new CLI.
> * Performance has not been a focus yet and "verbose" logging is built-in by
>   default to facilitate bug reporting. We expect this to slow down Babeltrace
>   significantly.

Just confirming this :-) In my quick experiments the time to convert CTF
to text is about 6x vs the stable-1.5 branch.


> * API documentation is incomplete.
> * Plugin man pages are not available.
> * Discarded events and dropped packets notifications are not emitted.
> * A number of tests are failing.
> * Built-in plugins are not re-linked into the application if they are modified.
> * The babeltrace-log utility is not present.
> * This version does not build on Windows (patches pending).

Where can I find the Windows/mingw patches?


> * API cleanups are planned (mostly namespacing changes).
>
> Let us know of all problems/bugs you encounter with this release!

Static linking still needs work, specifically case #3 from this comment:

https://bugs.lttng.org/issues/1055#note-2

Building on Fedora 25 with 'make LDFLAGS=-all-static' gets:

../lib/.libs/libbabeltrace.a(common.o): In function `bt_get_home_dir':
/home/nathanl/src/babeltrace/tmp/native/all/common/../../../../common/common.c:138: warning: Using 'getpwuid' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking
/usr/lib/gcc/x86_64-redhat-linux/6.3.1/../../../../lib64/libglib-2.0.a(libglib_2_0_la-gutils.o): In function `g_get_user_database_entry':
(.text+0xdc): warning: Using 'getpwnam_r' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking
/usr/lib/gcc/x86_64-redhat-linux/6.3.1/../../../../lib64/libglib-2.0.a(libglib_2_0_la-gutils.o): In function `g_get_user_database_entry':
(.text+0x114): warning: Using 'getpwuid_r' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking
/usr/bin/ld: dynamic STT_GNU_IFUNC symbol `strcmp' with pointer equality in `/usr/lib/gcc/x86_64-redhat-linux/6.3.1/../../../../lib64/libc.a(strcmp.o)' can not be used when making an executable; recompile with -fPIE and relink with -pie
collect2: error: ld returned 1 exit status

The getpwuid and getpwnam_r warnings are raised due to code that seems
intended to load plugins from the user's home directory; I wonder if
that facility could made configurable.  Or is there another way to deal
with this?

The STT_GNU_IFUNC strcmp error implicates export-dynamic, I think.
Still looking into it.