linux-kernel - Re: [PATCH v0 07/71] perf tools: Record whether a dso is 64-bit

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Message-ID: <20131211195419.GF1458@ghostprotocols.net>
Date:	Wed, 11 Dec 2013 16:54:19 -0300
From:	Arnaldo Carvalho de Melo <acme@...stprotocols.net>
To:	David Ahern <dsahern@...il.com>
Cc:	Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Ingo Molnar <mingo@...hat.com>, linux-kernel@...r.kernel.org,
	Frederic Weisbecker <fweisbec@...il.com>,
	Jiri Olsa <jolsa@...hat.com>, Mike Galbraith <efault@....de>,
	Namhyung Kim <namhyung@...il.com>,
	Paul Mackerras <paulus@...ba.org>,
	Stephane Eranian <eranian@...gle.com>,
	Andi Kleen <ak@...ux.intel.com>,
	Adrian Hunter <adrian.hunter@...el.com>
Subject: Re: [PATCH v0 07/71] perf tools: Record whether a dso is 64-bit

Em Wed, Dec 11, 2013 at 12:26:21PM -0700, David Ahern escreveu:
> On 12/11/13, 5:36 AM, Alexander Shishkin wrote:
> >diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c
> >index a0c7c59..80817ec 100644
> >--- a/tools/perf/util/dso.c
> >+++ b/tools/perf/util/dso.c
> >@@ -446,6 +446,7 @@ struct dso *dso__new(const char *name)
> >  		dso->cache = RB_ROOT;
> >  		dso->symtab_type = DSO_BINARY_TYPE__NOT_FOUND;
> >  		dso->data_type   = DSO_BINARY_TYPE__NOT_FOUND;
> >+		dso->is_64_bit = (sizeof(void *) == 8);
> 
> Isnt' that going to record the bitness of perf when it is compiled?

Right, it will. Its just a default, I assume this will be reset after
the DSO is loaded, i.e. the ELF file gets accessed, no?

Which then would make this init to be just a distraction, no?

I wonder if we couldn't extern PERF_RECORD_MMAP to have the binary type
encoded there somehow...

> >  		dso->loaded = 0;
> >  		dso->rel = 0;
> >  		dso->sorted_by_name = 0;
> >diff --git a/tools/perf/util/dso.h b/tools/perf/util/dso.h
> >index 384f2d9..62680e1 100644
> >--- a/tools/perf/util/dso.h
> >+++ b/tools/perf/util/dso.h
> >@@ -91,6 +91,7 @@ struct dso {
> >  	u8		 annotate_warned:1;
> >  	u8		 sname_alloc:1;
> >  	u8		 lname_alloc:1;
> >+	u8		 is_64_bit:1;
> 
> The is_64_bit name seems a bit hardcoded. We need something similar
> for perf-trace to set the audit machine type for resolving syscalls.
> How about having this field set a machine type rather than a
> "64-bit" flag?
> 
> David
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