Re: [PATCH] perf, tools: Support srccode output

[Andi Kleen]

On Wed, Dec 05, 2018 at 01:28:38PM +0100, Jiri Olsa wrote:
> On Mon, Dec 03, 2018 at 04:18:48PM -0800, Andi Kleen wrote:
> > From: Andi Kleen <ak@xxxxxxxxxxxxxxx>
> > 
> > When looking at PT or brstackinsn traces with perf script
> > it can be very useful to see the source code. This adds a simple
> > facility to print them with perf script, if the information
> > is available through dwarf
> > 
> > % perf record ...
> > % perf script -F insn,ip,sym,srccode
> > ...
> > 
> >           4004c6 main
> > 5               for (i = 0; i < 10000000; i++)
> >            4004cd main
> > 5               for (i = 0; i < 10000000; i++)
> >            4004c6 main
> > 5               for (i = 0; i < 10000000; i++)
> >            4004cd main
> > 5               for (i = 0; i < 10000000; i++)
> >            4004cd main
> > 5               for (i = 0; i < 10000000; i++)
> >            4004cd main
> > 5               for (i = 0; i < 10000000; i++)
> >            4004cd main
> > 5               for (i = 0; i < 10000000; i++)
> >            4004cd main
> > 5               for (i = 0; i < 10000000; i++)
> >            4004b3 main
> > 6                       v++;
> > 
> > % perf record -b ...
> > % perf script -F insn,ip,sym,srccode,brstackinsn
> > 
> > ...
> >        main+22:
> >         0000000000400543        insn: e8 ca ff ff ff            # PRED
> > |18                     f1();
> >         f1:
> >         0000000000400512        insn: 55
> > |10       {
> >         0000000000400513        insn: 48 89 e5
> >         0000000000400516        insn: b8 00 00 00 00
> > |11             f2();
> >         000000000040051b        insn: e8 d6 ff ff ff            # PRED
> >         f2:
> >         00000000004004f6        insn: 55
> > |5        {
> >         00000000004004f7        insn: 48 89 e5
> >         00000000004004fa        insn: 8b 05 2c 0b 20 00
> > |6              c = a / b;
> >         0000000000400500        insn: 8b 0d 2a 0b 20 00
> >         0000000000400506        insn: 99
> >         0000000000400507        insn: f7 f9
> >         0000000000400509        insn: 89 05 29 0b 20 00
> >         000000000040050f        insn: 90
> > |7        }
> >         0000000000400510        insn: 5d
> >         0000000000400511        insn: c3                        # PRED
> >         f1+14:
> >         0000000000400520        insn: b8 00 00 00 00
> > |12             f2();
> >         0000000000400525        insn: e8 cc ff ff ff            # PRED
> >         f2:
> >         00000000004004f6        insn: 55
> > |5        {
> >         00000000004004f7        insn: 48 89 e5
> >         00000000004004fa        insn: 8b 05 2c 0b 20 00
> > |6              c = a / b;
> > 
> > Not supported for callchains currently, would need some
> > layout changes there.
> 
> nice, works nicely, especialy with --xed
> 
> Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx>
> 
> I need to check, but is there a way to make this work with
> perf-with-kcore script? looks like we endup with kcore and
> won't allow vmlinux lookups for debug info

Hmm, probably not currently. Would somehow need to point
to the debuginfo. Perhaps if /proc/kcore was fixed
to report the debugid, and then could find it this way.

Or we could add an option to perf report to add a vmlinux
only for debug info that is not used for reading the code.

-andi