about /proc in preference to ptrace

[vera0010]

I see the following text at page of gdb-announce 2002-12-11:

GDB 5.3 released!
......
*** Changes in GDB 5.3:

* GNU/Linux shared library multi-threaded performance improved.

When debugging a multi-threaded application on GNU/Linux, GDB now uses '/proc', in preference to 'ptrace' for memory reads. 
......
It's annoounced by Mr.Andrew Cagney.

May I ask any questions about:
1) Is it the same as multi-process application debugging on GNU/Linux?
2) Does gdb stop the running process by '/proc'?
3) Please tell me how to do, if gdb can't stop it by /proc interface.

______________________________________

===================================================================
¶©·Ç³£Ð¦»°³é´ó½± ²ÊÆÁÊÖ»úÒ»ÌìÒ»²¿! (http://sms.sina.com.cn/act/fcxhhd.html)