[ltt-dev] problems with ust

Sylvain Geneves sylvain.geneves at inrialpes.fr
Tue Mar 30 08:25:48 EDT 2010

Hi all,

I've pulled UST from git yesterday, and noticed some errors, and some
are confusing me...

first of all, i have a problem for compiling my program (when i include
marker.h), it gives the following error :

In file included from /usr/local/include/ust/kcompat/kcompat.h:64,
                 from /usr/local/include/ust/kernelcompat.h:21,
                 from /usr/local/include/ust/marker.h:31,
                 from task.lbc.C:4:
/usr/local/include/ust/kcompat/jhash.h: In function ‘u32 jhash(const
void*, u32, u32)’:
/usr/local/include/ust/kcompat/jhash.h:47: error: invalid conversion
from ‘const void*’ to ‘const u8*’

seems like it lacks a cast somewhere, which i added. After that it
compiles fine, and there goes another problem :

when i run :
usttrace -l ./myprog

i've got the following output (with debug flags enabled):

myprog is calling clone via pthread_create. I have instrumented it with
a line like this, which is executed many times (almost 4 million calls):
  trace_mark(main, myevent, "calling cb" );

Here's what i see in the resulting trace directory:


it seems that all traces aren't recorded (some metadata and ust are zero
size), i can't understand why, i must be missing something here... ?

also, when using lttv, it says "Cannot open trace : maybe you should
enter in the trace directory to select it ?"
i note that lttv can open a subdirectory (like
in my example), but obviously all i can see is a subset of what really

i would really appreciate if you could show me what i'm doing wrong.


PS: i use userspace-rcu-0.4.3 and the git version of ust and lttv.

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