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

From: Andi Kleen
Date: Wed Dec 05 2018 - 12:33:10 EST


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