Subject: Re: [PATCH v5 1/1] powerpc/perf: Adjust callchain based on DWARF debug info

From: Sukadev Bhattiprolu <[email-masked]>
Date: Tue, 23 Sep 2014 09:26:23 -0700

Aaro Koskinen [[email-masked]] wrote:
| Hi,
| 
| On Wed, Jun 25, 2014 at 08:49:03AM -0700, Sukadev Bhattiprolu wrote:
| > powerpc/perf: Adjust callchain based on DWARF debug info
| > 
| > When saving the callchain on Power, the kernel conservatively saves excess
| > entries in the callchain. A few of these entries are needed in some cases
| > but not others. We should use the DWARF debug information to determine
| > when the entries are  needed.
| 
| This patch breaks perf compilation if DWARF support is not present.
| DWARF support is auto-detected early in the build, so IMHO either user
| should be informed to install the needed stuff, or the build should
| succeed with limited functionality.
| 
| arch/powerpc/util/skip-callchain-idx.c:13:19: fatal error: dwarf.h: No such file or directory #include <dwarf.h>
|                    ^
| compilation terminated.

Yes. Sorry. Anton fixed this recently:

	https://lkml.org/lkml/2014/9/19/29

Sukadev