linux-kernel - Re: [PATCH/RFC] perf report: Add option to change offset format when address is specified as a sort

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Date:   Sat, 23 Dec 2017 00:59:41 +0100
From:   Jiri Olsa <jolsa@...hat.com>
To:     Aaron Tomlin <atomlin@...hat.com>
Cc:     acme@...nel.org, jolsa@...hat.com, mingo@...hat.com,
        alexander.shishkin@...ux.intel.com, namhyung@...nel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH/RFC] perf report: Add option to change offset format when
 address is specified as a sort_key

On Fri, Dec 15, 2017 at 03:35:10PM +0000, Aaron Tomlin wrote:
> With --call-graph option, a user can choose to display call chains with a
> specific sort_key. The sort_key can be either: function, address or srcline.
> By default, when the address is specified as the sort_key, the offset (i.e.
> symbol + offset) is provided in decimal (base 10) form.
> This is because in __get_srcline() we use PRIu64 to display the offset.
> This may or may not be desirable.
> 
> This patch adds a new option --hex, to change the offset format to
> hexidecimal. Note, this can only be used with the -g, --call-graph option
> when address is specified as a sort_key.  When this option is not
> specified, the default behavior is used, which is to display the offset
> in decimal form.
> 
> Before:
> 
> $ ./perf report -n --fields=overhead,sample,period,pid,symbol --stdio \
> > -g graph,callee,address --percent-limit 10 --no-children
> [ ... ]
>     10.87%             1     506940477     15:migration/3   [k] _spin_trylock
>             |
>             ---_spin_trylock +13
>                double_lock_balance +48
>                schedule +2007
>                migration_thread +613
>                kthread +158
>                child_rip +10
> 
> After:
> 
> $ ./perf report -n --fields=overhead,sample,period,pid,symbol --stdio \
> > -g graph,callee,address --percent-limit 10 --hex --no-children
> [ ... ]
>     10.87%             1     506940477     15:migration/3   [k] _spin_trylock
>             |
>             ---_spin_trylock +0xd
>                double_lock_balance +0x30
>                schedule +0x7d7
>                migration_thread +0x265
>                kthread +0x9e
>                child_rip +0xa

not sure we've already discussed that, but this could be default?

if not, I think the hex option should be part of -g option arg, maybe like:

  -g graph,callee,xaddress

but default hex seems better to me, thoughts?

jirka