Re: [PATCH] perf util: Display warning when perf report/annotate is missing some libs

[Jin, Yao]

On 1/11/2018 11:30 PM, Jiri Olsa wrote:
> On Thu, Jan 11, 2018 at 07:03:06PM +0800, Jin Yao wrote:
> > We keep having bug reports that when users build perf on their own,
>
> we already have same warnings during the build

Yes, there will be warnings displayed during the build if some libraries 
are missing.

While I do find the users (especially the new perf user) don't notice 
the warning. They only care about the success of build.

Once they use this perf version and find something working strangely, 
they will say that perf may have bug. :(

> > but they don't install some needed libraries like libelf, libbfd/libibery.
>
> how about saying that in the symbol column,
> instead of poluting report's output, like:
>
> 	$ perf report --stdio
>
> 	# Overhead  Command  Shared Object     Symbol (disabled)
> 	# ........  .......  ................  ......................

I just think it'd better provide some hints to user. For example, 
"symbol is disabled and you need to install libelf/xxx", say something 
like that.

But it looks the column can't contain too much information (i.e. no more 
space to contain the entire hints).

Any idea? Or just add this warning in verbose mode?

> also your change does not affect tui mode
>
> annotation for some reason does not start at all.. could be
> little more verbose ;-)
>
> jirka

Yes, it doesn't affect tui mode.

Or we just add this warning in verbose mode?

e.g. perf report -v?

Thanks
Jin Yao