From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Cagney To: Eric Paire Cc: Mark Kettenis , "H . J . Lu" , GDB Subject: Re: Is the current gdb 5.1 broken for Linuxthreads? Date: Wed, 19 Sep 2001 13:39:00 -0000 Message-id: <3BA9025B.9080302@cygnus.com> References: <200109191438.f8JEcoR29295@mailhost.ri.silicomp.fr> X-SW-Source: 2001-09/msg00168.html > I already started a thread to explain that that stopping all threads in > a synchronous way was an illusion: Think of a 2-way processor on which > 2 threads are running on each processor: If one thread stops, the time > required by one processor to handle the trap, discover that others > threads must be stopped, makwe the interprocessor request, ... allows > the other thread to run thousands of instructions on the second > processor before being stopped. The result is that you think all threads > have stopped at the same time, while it's false, even if you have the best > interface you can think of. Just an aside, everyone will agree with your point that synchronized thread stop model is an illusion. However, that doesn't make the model/illusion wrong. Most other systems still make a synchronised halt interface available since it is simple and fast - the complexity of having to suspend all related threads being constrained to the kernel. As a separate issue, it would be good if GDB was able to control threads with a finer guranularity then all/none running. enjoy, Andrew