From: Pedro Alves Date: Wed, 15 Oct 2014 21:44:00 +0000 (+0100) Subject: remote: get rid of all the T packets when syncing the thread list X-Git-Url: http://git.efficios.com/?a=commitdiff_plain;h=ab970af19746364a4f236bebc238ebb036adc898;hp=e8032dde10b743253125d7defb5f5503b21c1d26;p=deliverable%2Fbinutils-gdb.git remote: get rid of all the T packets when syncing the thread list This commit avoids the prune_threads call in the remote target's target_update_thread_list's implementation, eliminating all the "thread alive" RSP traffic (one packet per thread) whenever we fetch the thread list. IOW, this: Sending packet: $Tp2141.2150#82...Packet received: OK Sending packet: $Tp2141.214f#b7...Packet received: OK Sending packet: $Tp2141.2141#82...Packet received: OK ... more T packets; it's one per previously known live thread ... Sending packet: $qXfer:threads:read::0,fff#03...Packet received: l\n\n\n\n\n Becomes: Sending packet: $qXfer:threads:read::0,fff#03...Packet received: l\n\n\n\n\n Tested on x86_64 Fedora 20, native gdbserver: - tests the qXfer:threads:read method. Tested on x86_64 Fedora 20, native gdbserver with qXfer:threads:read force-disabled in gdbserver: - So that GDB falls back to the qfThreadInfo/qsThreadInfo method. And also manually smoked tested force disabling both qXfer:threads:read and qfThreadInfo/qsThreadInfo in gdbserver. gdb/ 2014-10-15 Pedro Alves * gdbthread.h (ALL_NON_EXITED_THREADS_SAFE): New macro. * remote.c (remote_update_thread_list): Skip calling prune_threads if any thread listing method is supported, and instead walk over the set of remote threads listed, deleting those that are not found in GDB's thread list. --- diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 3a6bffdcf3..abad94504a 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,11 @@ +2014-10-15 Pedro Alves + + * gdbthread.h (ALL_NON_EXITED_THREADS_SAFE): New macro. + * remote.c (remote_update_thread_list): Skip calling prune_threads + if any thread listing method is supported, and instead walk over + the set of remote threads listed, deleting those that are not + found in GDB's thread list. + 2014-10-15 Pedro Alves * ada-tasks.c (print_ada_task_info, task_command_1): Adjust. diff --git a/gdb/gdbthread.h b/gdb/gdbthread.h index 1ed98a23bb..937bd55cd6 100644 --- a/gdb/gdbthread.h +++ b/gdb/gdbthread.h @@ -354,6 +354,14 @@ extern struct thread_info *iterate_over_threads (thread_callback_func, void *); for (T = thread_list; T; T = T->next) \ if ((T)->state != THREAD_EXITED) +/* Like ALL_NON_EXITED_THREADS, but allows deleting the currently + iterated thread. */ +#define ALL_NON_EXITED_THREADS_SAFE(T, TMP) \ + for ((T) = thread_list; \ + (T) != NULL ? ((TMP) = (T)->next, 1): 0; \ + (T) = (TMP)) \ + if ((T)->state != THREAD_EXITED) + extern int thread_count (void); /* Switch from one thread to another. */ diff --git a/gdb/remote.c b/gdb/remote.c index cd85fd5986..98d3f2a57f 100644 --- a/gdb/remote.c +++ b/gdb/remote.c @@ -2762,9 +2762,7 @@ remote_update_thread_list (struct target_ops *ops) struct remote_state *rs = get_remote_state (); struct threads_listing_context context; struct cleanup *old_chain; - - /* Delete GDB-side threads no longer found on the target. */ - prune_threads (); + int got_list = 0; context.items = NULL; old_chain = make_cleanup (clear_threads_listing_context, &context); @@ -2778,8 +2776,31 @@ remote_update_thread_list (struct target_ops *ops) { int i; struct thread_item *item; + struct thread_info *tp, *tmp; + + got_list = 1; + + /* CONTEXT now holds the current thread list on the remote + target end. Delete GDB-side threads no longer found on the + target. */ + ALL_NON_EXITED_THREADS_SAFE (tp, tmp) + { + for (i = 0; + VEC_iterate (thread_item_t, context.items, i, item); + ++i) + { + if (ptid_equal (item->ptid, tp->ptid)) + break; + } - /* Now add threads we don't know about yet to our list. */ + if (i == VEC_length (thread_item_t, context.items)) + { + /* Not found. */ + delete_thread (tp->ptid); + } + } + + /* And now add threads we don't know about yet to our list. */ for (i = 0; VEC_iterate (thread_item_t, context.items, i, item); ++i) @@ -2803,6 +2824,15 @@ remote_update_thread_list (struct target_ops *ops) } } + if (!got_list) + { + /* If no thread listing method is supported, then query whether + each known thread is alive, one by one, with the T packet. + If the target doesn't support threads at all, then this is a + no-op. See remote_thread_alive. */ + prune_threads (); + } + do_cleanups (old_chain); }