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Date: Wed, 25 Sep 2013 09:31:13 +0200 From: Jiri Olsa <jolsa@...hat.com> To: Jean Pihet <jean.pihet@...aro.org> Cc: Will Deacon <will.deacon@....com>, Ingo Molnar <mingo@...nel.org>, Arnaldo Carvalho de Melo <acme@...stprotocols.net>, "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, "linaro-kernel@...ts.linaro.org" <linaro-kernel@...ts.linaro.org>, "linux-arm-kernel@...ts.infradead.org" <linux-arm-kernel@...ts.infradead.org>, "patches@...aro.org" <patches@...aro.org> Subject: Re: [PATCH 3/4] perf tools: Check libunwind for availability of dwarf parsing feature On Wed, Sep 25, 2013 at 08:53:44AM +0200, Jean Pihet wrote: > Hi Jiri, > > On 24 September 2013 19:43, Jiri Olsa <jolsa@...hat.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@....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 libunwind > > config/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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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