linux-kernel - Re: [PATCH v3 3/7] perf tools: Remove the logical that skip buildid cache if symfs is given

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Date:	Thu, 12 May 2016 14:23:37 -0600
From:	David Ahern <dsahern@...il.com>
To:	Arnaldo Carvalho de Melo <arnaldo.melo@...il.com>
Cc:	He Kuang <hekuang@...wei.com>, peterz@...radead.org,
	mingo@...hat.com, alexander.shishkin@...ux.intel.com,
	jolsa@...hat.com, wangnan0@...wei.com, jpoimboe@...hat.com,
	ak@...ux.intel.com, eranian@...gle.com, namhyung@...nel.org,
	adrian.hunter@...el.com, sukadev@...ux.vnet.ibm.com,
	masami.hiramatsu.pt@...achi.com, tumanova@...ux.vnet.ibm.com,
	kan.liang@...el.com, penberg@...nel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 3/7] perf tools: Remove the logical that skip buildid
 cache if symfs is given

On 5/12/16 7:09 AM, Arnaldo Carvalho de Melo wrote:
> Em Thu, May 12, 2016 at 08:43:12AM +0000, He Kuang escreveu:
>> Symfs dir and buildid dir are two places that perf looks into for
>> symbols, currently, if symfs dir is given, buildid-cache is skipped.
>>
>> In the cross-platform perf record/script scenario, we need vdsos in
>> buildid-cache dir and other libs in symfs dir at the same time. And
>> consider that the binaries indexed by buildid do not cause ambiguity,
>> this patch simply removes that logical.
>
> Makes perfect sense, David, do you have any concern? Can I have your
> Acked-by?

seems odd to me you want to look in the buildid-cache when a symfs is 
given. The point of symfs was "go look for everything under here."

I believe dso__load is going to hit DSO_BINARY_TYPE__BUILD_ID_CACHE 
before any of the others and there are probably cases where a stale 
cache entry would be hit before a build tree entry (e.g., symfs).

What about putting the build id cache under the symfs? so instead of 
dropping the symfs check and it to the path for the build id cache.