Re: [PATCH v3 3/7 UPDATE] perf tools: Add option for the path of buildid dsos under symfs

[David Ahern]

On 5/14/16 2:19 AM, He Kuang wrote:
> 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. For
> the reason that to have every single file opened by perf is relative
> to symfs dirctory, perf skips the buildid dir if symfs is given.
>
> This patch references the buildid dir under symfs if '--symfs' is
> used, and adds new option '--dso-prefix' to specify the subdir path in
> symfs which contains the buildid dsos.

In the previous version of this patch you just wanted to drop the symfs 
check. That means there is a path that perf searches for buildid files 
and reading it worked for you. Why is adding symsfs to that path not 
enough? ie., Why do you need to specify a different location under the 
symfs?