On Wed, Sep 25, 2013 at 08:53:44AM +0200, Jean Pihet wrote:
Hi Jiri,
On 24 September 2013 19:43, Jiri Olsa jolsa@redhat.com wrote:
On Tue, Sep 24, 2013 at 02:03:47PM +0200, Jean Pihet wrote:
Hi Jiri, Will,
On 24 September 2013 12:06, Will Deacon will.deacon@arm.com wrote:
On Tue, Sep 24, 2013 at 10:34:50AM +0100, Jiri Olsa wrote:
On Tue, Sep 24, 2013 at 10:55:32AM +0200, Jean Pihet wrote:
Ping on the series. The two patches above (3/4 and 4/4) are generic while the two others are impacting ARM only. Is it possible to get an Ack for the generic ones?
I'm fine with those changes.. still I'm sort of worried about current DWARF unwind users (but not sure if there're any), who depends on packaged libunwind compiled without --enable-debug-frame option.
Since x86 is the only architecture using libunwind with perf at the moment, and I'd expect it to use .eh_frame for unwinding, I'm also not sure there are any existing users to worry about.
Right
I've seen your libunwind patch to make it default, but not sure if it was accepted.. if not, maybe we should detect this and build that code conditionaly.
It certainly defaults to "on" for ARM, but other architectures have to enable it explicitly afaict.
Yes that is correct. This patch (3/4) detects if the debug frame code is enabled in libunwind and uses the lib only if it is the case.
My concern is about users (again, not sure if there are any ;-) ) that use this with packaged libunwind compiled without --enable-debug-frame option.
For them perf will consider libunwind as 'not available' with your changes:
... CHK libunwindconfig/Makefile:223: No libunwind found, disabling post unwind support. Please install libunwind-dev[el] >= 1.1 ...
and they'll need to compile their own libunwind (thats the case on Fedora).
This could be solved by detecting this and make your code conditional as attached below (not much tested).
Ok that makes sense. Let me integrate this in the patch series, test it (on ARM and x86) and re-submit. Is that OK?
that'd be great
thanks, jirka