thread.c: micro-optimize thread create/join

* thread.c (struct join_arg): restructure and make smaller
  (thread_join_sleep): avoid timeofday() call if forever
  (thread_join): pass join_arg.delay directly
  (rb_thread_inspect_msg): remove, inline into rb_thread_inspect
  (rb_thread_inspect): reduce branching and string creation
* thread_pthread.c (native_set_thread_name): create string directly
  to avoid reparsing. [Misc #10723]

This reduces time in benchmark/bm_vm_thread_create_join.rb by
a few percent.

Minor improvements only:

target 0: 2.1.5 (ruby 2.1.5p273 (2014-11-13 revision 48405) [x86_64-linux])
target 1: trunk (ruby 2.3.0dev (2015-01-16 trunk 49282) [x86_64-linux])
target 2: built (ruby 2.3.0dev (2015-01-16 trunk 49282) [x86_64-linux])

benchmark results:
minimum results in each 3 measurements.
Execution time (sec)
name                    2.1.5   trunk   built
vm_thread_create_join   1.049   1.242   1.138

Speedup ratio: compare with the result of `2.1.5' (greater is better)
name                    trunk   built
vm_thread_create_join   0.845   0.923

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@49430 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 24 insertions, 25 deletions

diff --git a/thread_pthread.c b/thread_pthread.c
index 7e4d36c479..3ef316c639 100644
--- a/thread_pthread.c
+++ b/thread_pthread.c
@@ -1447,36 +1447,35 @@ timer_thread_sleep(rb_global_vm_lock_t* unused)
 # define SET_THREAD_NAME(name) (void)0
 #endif
 
-static VALUE rb_thread_inspect_msg(VALUE thread, int show_enclosure, int show_location, int show_status);
-
 static void
 native_set_thread_name(rb_thread_t *th)
 {
 #if defined(__linux__) && defined(PR_SET_NAME)
-    VALUE str;
-    char *name, *p;
-    char buf[16];
-    size_t len;
-
-    str = rb_thread_inspect_msg(th->self, 0, 1, 0);
-    name = StringValueCStr(str);
-    if (*name == '@')
-        name++;
-    p = strrchr(name, '/'); /* show only the basename of the path. */
-    if (p && p[1])
-        name = p + 1;
-
-    len = strlen(name);
-    if (len < sizeof(buf)) {
-        memcpy(buf, name, len);
-        buf[len] = '\0';
-    }
-    else {
-        memcpy(buf, name, sizeof(buf)-2);
-        buf[sizeof(buf)-2] = '*';
-        buf[sizeof(buf)-1] = '\0';
+    if (!th->first_func && th->first_proc) {
+	VALUE loc = rb_proc_location(th->first_proc);
+	if (!NIL_P(loc)) {
+	    const VALUE *ptr = RARRAY_CONST_PTR(loc); /* [ String, Fixnum ] */
+	    char *name, *p;
+	    char buf[16];
+	    size_t len;
+	    int n;
+
+	    name = RSTRING_PTR(ptr[0]);
+	    p = strrchr(name, '/'); /* show only the basename of the path. */
+	    if (p && p[1])
+		name = p + 1;
+
+	    n = snprintf(buf, sizeof(buf), "%s:%d", name, NUM2INT(ptr[1]));
+	    rb_gc_force_recycle(loc); /* acts as a GC guard, too */
+
+	    len = (size_t)n;
+	    if (len >= sizeof(buf)) {
+		buf[sizeof(buf)-2] = '*';
+		buf[sizeof(buf)-1] = '\0';
+	    }
+	    SET_THREAD_NAME(buf);
+	}
     }
-    SET_THREAD_NAME(buf);
 #endif
 }