From 273dadf2c20b93ef579367c42c255fcf4a3a2522 Mon Sep 17 00:00:00 2001 From: Simon Marchi Date: Fri, 28 May 2021 00:33:35 -0400 Subject: [PATCH] gdb: optimize check for resumed threads with pending wait status in maybe_set_commit_resumed_all_targets Consider a test case where many threads (thousands) keep hitting a breakpoint whose condition evaluates to false. maybe_set_commit_resumed_all_targets is called at each handled event, when the scoped_disable_commit_resumed object in fetch_inferior_event is reset_and_commit-ed. One particularly expensive check in there is whether the target has at least one resumed thread with a pending wait status (in which case, we don't want to commit the resumed threads, as we want to consume this status first). It is currently implemented as walking all threads of the target. Since we now maintain a per-target list of resumed threads with pending status, we can do this check efficiently, by checking whether that list is empty or not. Add the process_stratum_target::has_resumed_with_pending_wait_status method for this, and use it in maybe_set_commit_resumed_all_targets. Change-Id: Ia1595baa1b358338f94fc3cb3af7f27092dad5b6 --- gdb/infrun.c | 10 +--------- gdb/process-stratum-target.h | 5 +++++ 2 files changed, 6 insertions(+), 9 deletions(-) diff --git a/gdb/infrun.c b/gdb/infrun.c index 6c652ea3677..bec8e83e193 100644 --- a/gdb/infrun.c +++ b/gdb/infrun.c @@ -2800,15 +2800,7 @@ maybe_set_commit_resumed_all_targets () status to report, handle it before requiring the target to commit its resumed threads: handling the status might lead to resuming more threads. */ - bool has_thread_with_pending_status = false; - for (thread_info *thread : all_non_exited_threads (proc_target)) - if (thread->resumed () && thread->has_pending_waitstatus ()) - { - has_thread_with_pending_status = true; - break; - } - - if (has_thread_with_pending_status) + if (proc_target->has_resumed_with_pending_wait_status ()) { infrun_debug_printf ("not requesting commit-resumed for target %s, a" " thread has a pending waitstatus", diff --git a/gdb/process-stratum-target.h b/gdb/process-stratum-target.h index f03728088d3..6bd8bc37b5e 100644 --- a/gdb/process-stratum-target.h +++ b/gdb/process-stratum-target.h @@ -88,6 +88,11 @@ public: target's "resumed with pending wait status" list. */ void maybe_remove_resumed_with_pending_wait_status (thread_info *thread); + /* Return true if this target has at least one resumed thread with a pending + wait status. */ + bool has_resumed_with_pending_wait_status () const + { return !m_resumed_with_pending_wait_status.empty (); } + /* The connection number. Visible in "info connections". */ int connection_number = 0; -- 2.30.2