Re: [PATCH] Correctly handle symbols in VDSO

Re: [PATCH] Correctly handle symbols in VDSO

[Jiri Olsa]

On Tue, Apr 08, 2014 at 07:24:22PM +0400, Vladimir Nikulichev wrote:
> Hi Namhyung,
> 
> On Apr 7, 2014, at 10:14 AM, Namhyung Kim <namhyung@kernel.org> wrote:
> 
> > Just one question below..
> > 
> >> 
> >> ---------------------------------------------------------------------------------------------------------------------------
> >> 
> >> perf tools: Adjust symbols in VDSO
> >> 
> >> Signed-off-by: Vladimir Nikulichev <nvs@tbricks.com>
> >> 
> >> diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
> >> index 3b7dbf5..9c8b23b 100644
> >> --- a/tools/perf/util/symbol-elf.c
> >> +++ b/tools/perf/util/symbol-elf.c
> >> @@ -6,6 +6,7 @@
> >> #include <inttypes.h>
> >> 
> >> #include "symbol.h"
> >> +#include "vdso.h"
> >> #include <symbol/kallsyms.h>
> >> #include "debug.h"
> >> 
> >> @@ -618,6 +619,8 @@ int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
> >> 		GElf_Shdr shdr;
> >> 		ss->adjust_symbols = (ehdr.e_type == ET_EXEC ||
> >> 				ehdr.e_type == ET_REL ||
> >> +				(dso->symsrc_filename == NULL &&
> > 
> > Is this really needed?  Just checking is_vdso_map() seems to work well
> > for me.  Did you have a specific reason to add it?
> > 
> 
> Nothing specific, just to don't call string operations in most cases. But here it is only a matter of coding style, of course.
> Attaching shorter version of the patch.
> 
> ----------------------------
> 
> perf tools: Adjust symbols in VDSO

hi,
could you please put explanation from first email
into the patch changelog?

cc-ing lkml

thanks,
jirka

Re: [PATCH] Correctly handle symbols in VDSO

[Jiri Olsa]

On Wed, Apr 09, 2014 at 10:46:13AM +0400, Vladimir Nikulichev wrote:
> Hi,
> 
> On Apr 8, 2014, at 7:41 PM, Jiri Olsa <jolsa@redhat.com> wrote:
> 
> > hi,
> > could you please put explanation from first email
> > into the patch changelog?
> > 
> > cc-ing lkml
> > 
> > thanks,
> > jirka
> 
> 
> OK, pasting it together:

ook

hum, your email's encoding kills my 'git am' :-\
also 'perf tools: Adjust symbols in VDSO' should go into the
email subject

I processed this patch by hand this time

thanks,
jirka

> 
> ---------------------------------------------------------------------------------------------------------------------------
> 
> perf tools: Adjust symbols in VDSO
> 
> pert-report doesn't resolve function names in VDSO:
> 
> $ perf report --stdio -g flat,0.0,15,callee --sort pid
> ...
>             8.76%
>                0x7fff6b1fe861
>                __gettimeofday
>                ACE_OS::gettimeofday()
> ...
> 
> In this case symbol values should be adjusted the same way as for executables, relocatable objects and prelinked libraries.
> 
> After fix:
> 
> $ perf report --stdio -g flat,0.0,15,callee --sort pid
> ...
>             8.76%
>                __vdso_gettimeofday
>                __gettimeofday
>                ACE_OS::gettimeofday()
> …
> 
> Signed-off-by: Vladimir Nikulichev <nvs@tbricks.com>
> 
> diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
> index 3b7dbf5..6864661 100644
> --- a/tools/perf/util/symbol-elf.c
> +++ b/tools/perf/util/symbol-elf.c
> @@ -6,6 +6,7 @@
> #include <inttypes.h>
> 
> #include "symbol.h"
> +#include "vdso.h"
> #include <symbol/kallsyms.h>
> #include "debug.h"
> 
> @@ -618,6 +619,7 @@ int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
> 		GElf_Shdr shdr;
> 		ss->adjust_symbols = (ehdr.e_type == ET_EXEC ||
> 				ehdr.e_type == ET_REL ||
> +				is_vdso_map(dso->short_name) ||
> 				elf_section_by_name(elf, &ehdr, &shdr,
> 						     ".gnu.prelink_undo",
> 						     NULL) != NULL);

Re: [PATCH] Correctly handle symbols in VDSO

[Jiri Olsa]

On Wed, Apr 09, 2014 at 05:35:46PM +0200, Jiri Olsa wrote:
> On Wed, Apr 09, 2014 at 10:46:13AM +0400, Vladimir Nikulichev wrote:
> > Hi,
> > 
> > On Apr 8, 2014, at 7:41 PM, Jiri Olsa <jolsa@redhat.com> wrote:
> > 
> > > hi,
> > > could you please put explanation from first email
> > > into the patch changelog?
> > > 
> > > cc-ing lkml
> > > 
> > > thanks,
> > > jirka
> > 
> > 
> > OK, pasting it together:
> 
> ook
> 
> hum, your email's encoding kills my 'git am' :-\
> also 'perf tools: Adjust symbols in VDSO' should go into the
> email subject
> 
> I processed this patch by hand this time

actually I'll have to ask you to resend your patch
with proper subject and coding, refer to:
  https://www.kernel.org/doc/Documentation/email-clients.txt

  "Emailed patches should be in ASCII or UTF-8 encoding only."

Please CC lkml (linux-kernel@vger.kernel.org). Strangely enough,
I don't see your patch there at the moment.. 

thanks,
jirka