Re: [PATCHv2 1/2] perf hists browser: Fix UI bug after fold/unfold

[Arnaldo Carvalho de Melo <acme@kernel.org>]

Em Wed, Mar 11, 2015 at 08:36:02PM +0800, He Kuang escreveu:
> In perf hists browser, the fold/unfold stat of each hist entry is
> recorded but hb->nr_callchain_rows loses its value after zoom out and
> zoom in back. This causes a wrong row cursor range that restrict user to
> move down anymore.
> 
> This bug can be reproduced as follows:
> 
>   $ perf record -g -e syscalls:* ls
>   $ perf report
> 
>     Available samples
>   ================================================================
>     2 syscalls:sys_enter_mprotect <= [enter one of the entries]
>     2 syscalls:sys_exit_mprotect
>     13 syscalls:sys_enter_brk
>     ...
> 
> In the hists brower, unfold some of the items, now the cursor can reach
> to any rows:
> 
>     Children      Self  Command  Shared Object          Symbol
>   ================================================================
>   -  100.00%   100.00%  ls       libuClibc-0.9.33.2.so  [.] lstat64
>   - lstat64
>        16.67% 0x6469702e64
>        8.33% 0x646970
>        8.33% 0x617461
>        8.33% 0x65
>   -   16.67%     0.00%  ls       [unknown]              [.]0x6469702e64
>      0x6469702e64 <= [cursor can reach to bottom line, everything is ok]
> 
> Now, zoom back to "Available samples" and enter again:
> 
>     Children      Self  Command  Shared Object          Symbol
>   ================================================================
>   -  100.00%   100.00%  ls       libuClibc-0.9.33.2.so  [.] lstat64
>   - lstat64
>        16.67% 0x6469702e64
>        8.33% 0x646970
>        8.33% 0x617461 <= [cursor may stop here, can't move down anymore]
>        8.33% 0x65
>   -   16.67%     0.00%  ls       [unknown]              [.]0x6469702e64
>      0x6469702e64
> 
> This patch recalculates hb->nr_callchain_rows to fix the bug.

Two nits below:
 
> Signed-off-by: He Kuang <hekuang@huawei.com>
> ---
>  tools/perf/ui/browsers/hists.c | 20 ++++++++++++++++++++
>  1 file changed, 20 insertions(+)
> 
> diff --git a/tools/perf/ui/browsers/hists.c b/tools/perf/ui/browsers/hists.c
> index 1106bb8..bef9ab0 100644
> --- a/tools/perf/ui/browsers/hists.c
> +++ b/tools/perf/ui/browsers/hists.c
> @@ -42,6 +42,7 @@ static void hist_browser__update_nr_entries(struct hist_browser *hb);
>  
>  static struct rb_node *hists__filter_entries(struct rb_node *nd,
>  					     float min_pcnt);
> +static int __hist_browser__get_folding(struct hist_browser *browser);

Why not move the whole function body to...
>  
>  static bool hist_browser__has_filter(struct hist_browser *hb)
>  {

Just before the only caller, i.e. here and...

> @@ -57,6 +58,7 @@ static u32 hist_browser__nr_entries(struct hist_browser *hb)
>  	else
>  		nr_entries = hb->hists->nr_entries;
>  
> +	hb->nr_callchain_rows = __hist_browser__get_folding(hb);
>  	return nr_entries + hb->nr_callchain_rows;
>  }
>  
> @@ -353,6 +355,24 @@ static void hist_entry__set_folding(struct hist_entry *he, bool unfold)
>  		he->nr_rows = 0;
>  }
>  
> +static int
> +__hist_browser__get_folding(struct hist_browser *browser)

Why use the __ prefix since there is no hist_browser__get_folding that
calls it and does something more?

Summary: please rename it to hist_browser__get_folding() and move it to
just before its only caller.

Also, besides these nits, are you Ok with this now Namhyung?

Thanks a lot for working on this!

- Arnaldo

> +{
> +	struct rb_node *nd;
> +	struct hists *hists = browser->hists;
> +	int unfolded_rows = 0;
> +
> +	for (nd = rb_first(&hists->entries);
> +	     (nd = hists__filter_entries(nd, browser->min_pcnt)) != NULL;
> +	     nd = rb_next(nd)) {
> +		struct hist_entry *he = rb_entry(nd, struct hist_entry, rb_node);
> +
> +		if (he->ms.unfolded)
> +			unfolded_rows += he->nr_rows;
> +	}
> +	return unfolded_rows;
> +}
> +
>  static void
>  __hist_browser__set_folding(struct hist_browser *browser, bool unfold)
>  {
> -- 
> 2.2.0.33.gc18b867