Re: [PATCH v3 2/2] Support interactive annotation of code without symbols

[Ravi Bangoria]

On 2/24/20 7:21 PM, Jiri Olsa wrote:
> On Mon, Feb 24, 2020 at 06:55:12PM +0530, Ravi Bangoria wrote:
> > Hi Jin,
> >
> > On 2/24/20 7:52 AM, Jin Yao wrote:
> > > For perf report on stripped binaries it is currently impossible to do
> > > annotation. The annotation state is all tied to symbols, but there are
> > > either no symbols, or symbols are not covering all the code.
> > >
> > > We should support the annotation functionality even without symbols.
> > >
> > > This patch fakes a symbol and the symbol name is the string of address.
> > > After that, we just follow current annotation working flow.
> > >
> > > For example,
> > >
> > > 1. perf report
> > >
> > > Overhead  Command  Shared Object     Symbol
> > >     20.67%  div      libc-2.27.so      [.] __random_r
> > >     17.29%  div      libc-2.27.so      [.] __random
> > >     10.59%  div      div               [.] 0x0000000000000628
> > >      9.25%  div      div               [.] 0x0000000000000612
> > >      6.11%  div      div               [.] 0x0000000000000645
> > >
> > > 2. Select the line of "10.59%  div      div               [.] 0x0000000000000628" and ENTER.
> > >
> > > Annotate 0x0000000000000628
> > > Zoom into div thread
> > > Zoom into div DSO (use the 'k' hotkey to zoom directly into the kernel)
> > > Browse map details
> > > Run scripts for samples of symbol [0x0000000000000628]
> > > Run scripts for all samples
> > > Switch to another data file in PWD
> > > Exit
> > >
> > > 3. Select the "Annotate 0x0000000000000628" and ENTER.
> > >
> > > Percentâ
> > >          â
> > >          â
> > >          â     Disassembly of section .text:
> > >          â
> > >          â     0000000000000628 <.text+0x68>:
> > >          â       divsd %xmm4,%xmm0
> > >          â       divsd %xmm3,%xmm1
> > >          â       movsd (%rsp),%xmm2
> > >          â       addsd %xmm1,%xmm0
> > >          â       addsd %xmm2,%xmm0
> > >          â       movsd %xmm0,(%rsp)
> > >
> > > Now we can see the dump of object starting from 0x628.
> >
> > If I press 'a' on address, it's not annotating. But if I annotate
> > by pressing enter, like you explained, it works. Is it intentional?
>
> I saw that too, but I thought it's unrelated issue,
> because we played with that just recently
>
> if you go through the 'enter' way and back, then the
> next time 'a' works ;-)

Yes.

I liked the series so I was trying out the patches. Just reporting issues I found...

jump/call arrows are also screwed up.. Like jump instruction is showing call arrows.
But these all are minor issues and can be fixed later on. I don't mind ;)

Ravi