[PATCH] PR breakpoints/15697: Remove =breakpoint-modified when hitting dprintf

[Marc Khouzam <marc dot khouzam at ericsson dot com>]

GDB currently sends a =breakpoint-modified for every dprintf hit.
This can cause performance degradation at the frontend.  The below
patch prevents GDB from sending this event for dprintf when the
event is triggered by the dprintf being hit.  This means the event
is not sent when the hit-count is incremented or the ignore-count
is decremented due to a hit.

https://sourceware.org/bugzilla/show_bug.cgi?id=15697

This was discussed last year:
http://sourceware.org/ml/gdb-patches/2013-03/msg00260.html

No regressions.

Ok?

Thanks

Marc

---

DPrintfs can be hit very often since they don't interrupt
the execution.  Having a =breakpoint-modified event at
every hit can cause performance degradation at the
frontend.  The only value in this event is to indicate that
the hit-count has changed.  For the hit-count value however,
it is sufficient for a frontend to get the latest value upon
request and not through an asynchronous event.

We also remove =breakpoint-modified when hitting a dprintf
and decrementing the ignore count.  If the ignore count is
set to a high number, the =breakpoint-modified could also
cause performance degradation as it will be sent at every
dprintf hit which decrements the ignore count.

2014-04-28  Marc Khouzam  <marc.khouzam@ericsson.com>

	PR breakpoints/15697
	* breakpoint.c (bpstat_check_breakpoint_conditions):
	Don't call observer_notify_breakpoint_modified for dprintf.
	* breakpoint.c (bpstat_stop_status): Ditto.
---
 gdb/breakpoint.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/gdb/breakpoint.c b/gdb/breakpoint.c
index f422998..25615eb 100644
--- a/gdb/breakpoint.c
+++ b/gdb/breakpoint.c
@@ -5378,7 +5378,8 @@ bpstat_check_breakpoint_conditions (bpstat bs, ptid_t ptid)
       bs->stop = 0;
       /* Increase the hit count even though we don't stop.  */
       ++(b->hit_count);
-      observer_notify_breakpoint_modified (b);
+      if (b->type != bp_dprintf)
+	observer_notify_breakpoint_modified (b);
     }	
 }
 
@@ -5515,7 +5516,8 @@ bpstat_stop_status (struct address_space *aspace,
 	  if (bs->stop)
 	    {
 	      ++(b->hit_count);
-	      observer_notify_breakpoint_modified (b);
+	      if (b->type != bp_dprintf)
+		observer_notify_breakpoint_modified (b);
 
 	      /* We will stop here.  */
 	      if (b->disposition == disp_disable)
-- 
1.7.9.5