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Re: Extending RSP with vCont;n and vCont;f
- From: Yao Qi <yao at codesourcery dot com>
- To: ILG.Robert <R dot ILG at bachmann dot info>
- Cc: "gdb-patches at sourceware dot org" <gdb-patches at sourceware dot org>
- Date: Fri, 4 Oct 2013 14:48:11 +0800
- Subject: Re: Extending RSP with vCont;n and vCont;f
- Authentication-results: sourceware.org; auth=none
- References: <7E3A266F5548C442BC08FA3038B5197C68449231 at ATFKEX06 dot bachmann dot at>
On 10/02/2013 11:08 PM, ILG.Robert wrote:
void
_initialize_remote (void)
{
@@ -12168,6 +12274,34 @@
&setlist,
&showlist);
+ add_setshow_boolean_cmd ("next-stepping", class_run,
+ &use_next_stepping, _("\
+ Enable or disable next stepping."), _("\
+ Show whether target-assisted next stepping is enabled."), _("\
+ If on, and the target supports it, when skipping over a source line, GDB\n\
+ tells the target to skip the next instruction itself instead of\n\
+ of issuing multiple single-steps. This speeds up source level\n\
+ stepping. If off, GDB always issues slower stepping mechanisms\n\
+ instead, even if next stepping is supported by the target. The default is on."),
Due to lack of description of these two packets, I have to understand
them from the help message of the command.
IIUC, it is similar to range-stepping, vCont;r except that start and
stop address are not provided to the stub. That means vCont;n requires
a smarter stub to know enough line table information to decide where to
stop.
An alternative to me is to teach your stub understand range stepping.
+ set_next_stepping,
+ show_next_stepping,
+ &setlist,
+ &showlist);
+
+ add_setshow_boolean_cmd ("finish-stepping", class_run,
+ &use_finish_stepping, _("\
+ Enable or disable finish stepping."), _("\
+ Show whether target-assisted finish stepping is enabled."), _("\
+ If on, and the target supports it, when stepping out of a function, GDB\n\
+ tells the target to step out of the corresponding stack frame itself.\n\
+ This speeds up source level stepping. If off, GDB issues slower\n\
+ stepping mechanisms instead, even if finish\n\
+ stepping is supported by the target. The default is on."),
GDB inserts a momentary breakpoint, resume the inferior and wait when
command "finish" is executed. I don't think GDB emits a large number of
RSP packets in this process. Do you have an experiment that vCont;f
packet improves performance to some extent?
--
Yao (éå)