Adding Jiri.
On 9/9/13 5:59 AM, Mark Hills wrote:
On Fri, 6 Sep 2013, Andi Kleen wrote:
Mark Hills <m...@pogo.org.uk> writes:
I have a pre-compiled .so library, which was given to me for profiling.
gdb can see a complete call stack -- both the library and my own code,
as expected.
But in perf the callgraph for the library is not present. I'm using
"perf record -g", and the callgraph for the other code is seen.
In what cases could gdb see the stack, but perf cannot?
No frame pointer.
Recompile with -fno-omit-frame-pointer
Or if you have a new enough perf, you can use -g dwarf to enable
dwarf backtracing, but it's very slow and also doesn't handle all
situations gdb handles.
Thank you, much appreciated.
A newer perf appears to need a newer kernel too, and it's not practical
for me to break away from the RedHat kernel at the moment (currently on
2.6.32-358.14.1.el6)
Any updates to RHEL6 for dwarf callchains?
David
Also I looked to cherry-pick the relevant patches, but it seems this is
non-trivial.
I'll speak to the author of the library in question but may have to
re-visit the dwarf behaviour; omit-frame-pointer may have been used with
performance in mind.
Thanks
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