Re: [PATCH 2/3] Be lazy about refreshing the windows in tui_show_frame_info (PR tui/13378)

[Pedro Alves <palves@redhat.com>]

On 06/30/2015 05:51 PM, Patrick Palka wrote:
> [ This version just changes tui_set_locator_info as you suggested.  ]
> 
> tui_show_frame_info is responsible for updating the visible windows
> following a change in frame information (that being the currently
> selected frame, PC, line number, etc).  Currently it always redraws and
> refreshes each window even if frame information has not changed.  This
> behavior is inefficient and helps contribute to the occassional
> flickering of the TUI as described in the mentioned PR.
> 
> This patch makes tui_show_frame_info refresh the windows only if frame
> information has changed.  Determining whether frame information has
> changed is done indirectly by determining whether the locator has
> changed.  This approach is convenient and yet sensible because the
> locator contains all the relevant info we need to check anyway: the
> current PC, the line number, the name of the executable and the name of
> the current function.  Probably only the PC is really necessary to
> check, but it doesn't hurt to check every field.
> 
> Effectively, with this patch, consecutive calls to select_frame with the
> same frame/PC no longer cause TUI's frame information to be updated
> multiple times.
> 
> gdb/ChangeLog:
> 
> 	* tui/tui-stack.c (tui_set_locator_info): Change prototype to
> 	return an int instead of void.  Return whether the locator
> 	window has changed.
> 	(tui_show_frame_info): If the locator info has not changed, then
> 	bail out early to avoid refreshing the windows.

OK.

Thanks,
Pedro Alves