Re: [PATCH v3 3/3] perf probe: Show better error message when failed to find variable

Ingo Molnar
2015-05-11T09:30:20Z

* He Kuang <hekuang@huawei.com> wrote:

> Indicate to check variable location range in error message when we got
> failed to find the variable.
>
> Before this patch:
>
> $ perf probe --add 'generic_perform_write+118 bytes'
> Failed to find the location of bytes at this address.
> Perhaps, it has been optimized out.
> Error: Failed to add events.
>
> After this patch:
> $ perf probe --add 'generic_perform_write+118 bytes'
> Failed to find the location of bytes at this address.

What does this sentence mean? I thought 'address' means 'location of
bytes'. So the address identifies the location and obviously we know
that. So this message wants to say something else.

> Perhaps, it has been optimized out.
> Use -V with --range option to show variable location range.

This suggestion is useful.

> Error: Failed to add events.

Thanks,

Ingo