[Feature #10602] Add new API rb_profile_thread_frames()

Add a new API rb_profile_thread_frames(), which is essentialy a
per-thread version of rb_profile_frames().

While the original rb_profile_frames() always returns results about the
current active thread obtained by GET_EC(), this new API takes a Thread
to be profiled as an argument.

This should come in handy when profiling I/O-bound programs such as
webapps, since this new API allows us to learn about Threads performing
I/O (which do not have the GVL).

Profiling worker threads (such as Sidekiq workers) may be another
application.

Implements [Feature #10602]

Co-authored-by: Mike Perham <mike@perham.net>

1 files changed, 16 insertions, 3 deletions

diff --git a/vm_backtrace.c b/vm_backtrace.c
index 34ebde0f0b..2414adae6e 100644
--- a/vm_backtrace.c
+++ b/vm_backtrace.c
@@ -1584,11 +1584,10 @@ rb_debug_inspector_backtrace_locations(const rb_debug_inspector_t *dc)
     return dc->backtrace;
 }
 
-int
-rb_profile_frames(int start, int limit, VALUE *buff, int *lines)
+static int
+thread_profile_frames(rb_execution_context_t *ec, int start, int limit, VALUE *buff, int *lines)
 {
     int i;
-    const rb_execution_context_t *ec = GET_EC();
     const rb_control_frame_t *cfp = ec->cfp, *end_cfp = RUBY_VM_END_CONTROL_FRAME(ec);
     const rb_control_frame_t *top = cfp;
     const rb_callable_method_entry_t *cme;
@@ -1650,6 +1649,20 @@ rb_profile_frames(int start, int limit, VALUE *buff, int *lines)
     return i;
 }
 
+int
+rb_profile_frames(int start, int limit, VALUE *buff, int *lines)
+{
+    rb_execution_context_t *ec = GET_EC();
+    return thread_profile_frames(ec, start, limit, buff, lines);
+}
+
+int
+rb_profile_thread_frames(VALUE thread, int start, int limit, VALUE *buff, int *lines)
+{
+    rb_thread_t *th = rb_thread_ptr(thread);
+    return thread_profile_frames(th->ec, start, limit, buff, lines);
+}
+
 static const rb_iseq_t *
 frame2iseq(VALUE frame)
 {