performance of multithreading gets gradually worse under gdb

[Pedro Alves]

On Friday 04 February 2011 15:55:51, Pedro Alves wrote:
> [Adding gdb-patches@]

...

> Okay, thanks, I've applied it.

"it" being...

-- 
Pedro Alves

2011-02-04  Pedro Alves  <pedro@codesourcery.com>

	gdb/
	* regcache.c (registers_changed_ptid): Don't explictly always
	clear `current_regcache'.  Only clear current_thread_ptid and
	current_thread_arch when PTID matches.  Only reinit the frame
	cache if PTID matches the current inferior_ptid.  Move alloca(0)
	call to ...
	(registers_changed): ... here.

---
 gdb/regcache.c |   28 +++++++++++++++++-----------
 1 file changed, 17 insertions(+), 11 deletions(-)

Index: src/gdb/regcache.c
===================================================================
--- src.orig/gdb/regcache.c	2011-02-01 15:27:37.000000000 +0000
+++ src/gdb/regcache.c	2011-02-04 11:56:49.273328004 +0000
@@ -530,6 +530,7 @@ void
 registers_changed_ptid (ptid_t ptid)
 {
   struct regcache_list *list, **list_link;
+  int wildcard = ptid_equal (ptid, minus_one_ptid);
 
   list = current_regcache;
   list_link = &current_regcache;
@@ -550,13 +551,24 @@ registers_changed_ptid (ptid_t ptid)
       list = *list_link;
     }
 
-  current_regcache = NULL;
+  if (wildcard || ptid_equal (ptid, current_thread_ptid))
+    {
+      current_thread_ptid = null_ptid;
+      current_thread_arch = NULL;
+    }
 
-  current_thread_ptid = null_ptid;
-  current_thread_arch = NULL;
+  if (wildcard || ptid_equal (ptid, inferior_ptid))
+    {
+      /* We just deleted the regcache of the current thread.  Need to
+	 forget about any frames we have cached, too.  */
+      reinit_frame_cache ();
+    }
+}
 
-  /* Need to forget about any frames we have cached, too.  */
-  reinit_frame_cache ();
+void
+registers_changed (void)
+{
+  registers_changed_ptid (minus_one_ptid);
 
   /* Force cleanup of any alloca areas if using C alloca instead of
      a builtin alloca.  This particular call is used to clean up
@@ -567,12 +579,6 @@ registers_changed_ptid (ptid_t ptid)
 }
 
 void
-registers_changed (void)
-{
-  registers_changed_ptid (minus_one_ptid);
-}
-
-void
 regcache_raw_read (struct regcache *regcache, int regnum, gdb_byte *buf)
 {
   gdb_assert (regcache != NULL && buf != NULL);