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

[Jin, Yao]

On 2/24/2020 9:56 PM, Ravi Bangoria wrote:
> 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
> > ÂÂ 20.67%Â divÂÂÂÂÂ libc-2.27.soÂÂÂÂÂ [.] __random_r
> > ÂÂ 17.29%Â divÂÂÂÂÂ libc-2.27.soÂÂÂÂÂ [.] __random
> > ÂÂ 10.59%Â divÂÂÂÂÂ divÂÂÂÂÂÂÂÂÂÂÂÂÂÂ [.] 0x0000000000000628
> > ÂÂÂ 9.25%Â divÂÂÂÂÂ divÂÂÂÂÂÂÂÂÂÂÂÂÂÂ [.] 0x0000000000000612
> > ÂÂÂ 6.11%Â divÂÂÂÂÂ divÂÂÂÂÂÂÂÂÂÂÂÂÂÂ [.] 0x0000000000000645
> >
> > 2. Select the line of "10.59%Â divÂÂÂÂÂ divÂÂÂÂÂÂÂÂÂÂÂÂÂÂ [.] 
> > 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
> > ÂÂÂÂÂÂÂ â
> > ÂÂÂÂÂÂÂ â
> >  â Disassembly of section .text:
> > ÂÂÂÂÂÂÂ 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)
> This might be an add on...
>
> Even though there are samples on a particular instruction, 'Percent' column
> is empty, I guess, because we don't have symbol length?
>
> Should we show 'global percent'? Or nr samples? Will it be useful?
>
> Ravi

As the mail I reply to Jiri, if we use the Jiri's idea, we can collect 
the hits for dummy symbols then we can show the percent of dummy symbol 
here.

Thanks
Jin Yao