Re: [GIT PULL] perf/urgent fixes

[Ingo Molnar]

* Arnaldo Carvalho de Melo <acme@xxxxxxxxxx> wrote:

> Em Mon, Oct 21, 2019 at 08:23:54AM +0200, Ingo Molnar escreveu:
> > Secondly, there also appears to be a TUI weirdness when the annotated 
> > kernel functions are small (or weird): the blue cursor is stuck at the 
> > top and I cannot move between the annotated instructions with the down/up 
> > arrow:
> > 
> > Samples: 13M of event 'cycles', 4000 Hz, Event count (approx.): 1272420588851
> > clear_page_rep  /usr/lib/debug/boot/vmlinux-5.4.0-rc3-custom-00557-gb6c81ae120e0 [Percent: local period]
> >   0.01 â     mov  $0x200,%ecx                                                                                                                                                                      â
> >        â   xorl %eax,%eax                                                                                                                                                                          â
> >   0.01 â     xor  %eax,%eax                                                                                                                                                                        â
> >        â   rep stosq                                                                                                                                                                               â
> >  99.27 â     rep  stos %rax,%es:(%rdi)                                                                                                                                                             â
> >        â   ret                                                                                                                                                                                     â
> >   0.71 â   â retq                         
> > 
> > I can still exit the screen with 'q', and can move around in larger 
> > annotated kernel functions. Not sure whether it's related to function 
> > size, or perhaps to the 'hottest' instruction that the cursor is normally 
> > placed at.
> 
> I couldn't reproduce this one so far, with another small function,
> clear_page_erms, what happens is that the cursor seems to be hidden at the
> bottom, if you press the "magic" 'D' hotkey it will tell (at the bottom of the
> screen) that the idx is at 18, which  for a function with just 8 output lines
> doesn't make sense:
> 
> Samples: 12K of event 'cycles', 4000 Hz, Event count (approx.): 2219443843
> clear_page_erms  /proc/kcore [Percent: local period]
> Percentâ                                                                 â
>        â                                                                 â
>        â                                                                 â
>        â    Disassembly of section load0:                                â
>        â                                                                 â
>        â    ffffffffab9d17c0 <load0>:                                    â
>        â      mov  $0x1000,%ecx                                          â
>        â      xor  %eax,%eax                                             â
> 100.00 â      rep  stos %al,%es:(%rdi)                                   â
>        â    â retq                                                       â
>                                                                          â
> 1: nr_ent=20, height=35, idx=18, top_idx=1, nr_asm_entries=8
> 
> Doesn't make sense, there aren't 20 entries nor the idx is 18, the
> nr_asm_entries is right, I'll try to follow up on this one...
> 
> But you can in these cases try to go on pressin the up arrow till the cursor
> appears, etc.

Yeah, I can reproduce this too - and don't see the original weirdness 
anymore. :-/

Will re-report if it happens again.

Thanks,

	Ingo