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  1. Mar 29, 2011
    • Ingo Molnar's avatar
      Merge branch 'core' of git://git.kernel.org/pub/scm/linux/kernel/git/rric/oprofile into perf/urgent · 1dfd7b49
      Ingo Molnar authored
      1dfd7b49
    • Andrew Lutomirski's avatar
      perf symbols: Fix vsyscall symbol lookup · 6c6804fb
      Andrew Lutomirski authored 
      

Perf can't currently trace into the vsyscall page.  It looks like it was
meant to work.

Tested on 2.6.38 and today's -git.

The bug is easy to reproduce.  Compile this:

int main()
{
	int i;
	struct timespec t;
	for(i = 0; i < 10000000; i++)
		clock_gettime(CLOCK_MONOTONIC, &t);
	return 0;
}

and run it through perf record; perf report.  The top entry shows
"[unknown]" and you can't zoom in.

It looks like there are two issues.  The first is a that a test for user
mode executing in kernel space is backwards.  (That's the first hunk
below).  The second (I think) is that something's wrong with the code
that generates lots of little struct dso objects for different sections
-- when it runs on vmlinux it results in bogus long_name values which
cause objdump to fail.

Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LPU-Reference: <AANLkTikxSw5+wJZUWNz++nL7mgivCh_Zf=2Kq6=f9Ce_@mail.gmail.com>
Signed-off-by: default avatarAndy Lutomirski <luto@mit.edu>
Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
      6c6804fb
  3. Mar 28, 2011
  5. Mar 27, 2011