[RFA] Addition to docs, non-stop mode vs remote caching

[RFA] Addition to docs, non-stop mode vs remote caching

[Doug Evans]

[resend, typo in address]

Hi.

Ok to check in?

2009-08-31  Doug Evans  <dje@google.com>

	* gdb.texinfo (Caching Data of Remote Targets): Add note on
	non-stop mode's affect on remote caching.

Index: doc/gdb.texinfo
===================================================================
RCS file: /cvs/src/src/gdb/doc/gdb.texinfo,v
retrieving revision 1.619
diff -u -p -r1.619 gdb.texinfo
--- doc/gdb.texinfo	31 Aug 2009 20:18:46 -0000	1.619
+++ doc/gdb.texinfo	1 Sep 2009 02:26:36 -0000
@@ -8427,8 +8427,14 @@ performance, because it reduces the over
 bundling memory reads and writes into large chunks.  Unfortunately, simply
 caching everything would lead to incorrect results, since @value{GDBN} 
 does not necessarily know anything about volatile values, memory-mapped I/O
-addresses, etc.  Therefore, by default, @value{GDBN} only caches data
-known to be on the stack.  Other regions of memory can be explicitly marked
+addresses, etc.  Furthermore, in non-stop mode (@pxref{Non-Stop Mode})
+memory can be changed @emph{while} a gdb command is executing.
+Therefore, by default, @value{GDBN} only caches data
+known to be on the stack.@footnote{In non-stop mode, it is moderately
+rare for a running thread to modify the stack of a stopped thread
+in a way that would interfere with a backtrace, and caching of
+stack reads provides a significant speed up of remote backtraces.}
+Other regions of memory can be explicitly marked
 cacheable; see @pxref{Memory Region Attributes}.
 
 @table @code