Prepare for radical source tree reorganization. zack/build-layout-experiment

All top-level files and directories are moved into a temporary storage
directory, REORG.TODO, except for files that will certainly still
exist in their current form at top level when we're done (COPYING,
COPYING.LIB, LICENSES, NEWS, README), all old ChangeLog files (which
are moved to the new directory OldChangeLogs, instead), and the
generated file INSTALL (which is just deleted; in the new order, there
will be no generated files checked into version control).

1 files changed, 103 insertions, 0 deletions

diff --git a/REORG.TODO/nptl/cond-perf.c b/REORG.TODO/nptl/cond-perf.c
new file mode 100644
index 0000000000..9c9488e274
--- /dev/null
+++ b/REORG.TODO/nptl/cond-perf.c
@@ -0,0 +1,103 @@
+#include <pthread.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <atomic.h>
+
+static pthread_cond_t cond1 = PTHREAD_COND_INITIALIZER;
+static pthread_mutex_t mut1 = PTHREAD_MUTEX_INITIALIZER;
+
+static pthread_cond_t cond2 = PTHREAD_COND_INITIALIZER;
+static pthread_mutex_t mut2 = PTHREAD_MUTEX_INITIALIZER;
+
+static bool last_round;
+static int ntogo;
+static bool alldone;
+
+
+static void *
+cons (void *arg)
+{
+  pthread_mutex_lock (&mut1);
+
+  do
+    {
+      if (atomic_decrement_and_test (&ntogo))
+	{
+	  pthread_mutex_lock (&mut2);
+	  alldone = true;
+	  pthread_cond_signal (&cond2);
+	  pthread_mutex_unlock (&mut2);
+	}
+
+      pthread_cond_wait (&cond1, &mut1);
+    }
+  while (! last_round);
+
+  pthread_mutex_unlock (&mut1);
+
+  return NULL;
+}
+
+
+int
+main (int argc, char *argv[])
+{
+  int opt;
+  int err;
+  int nthreads = 10;
+  int nrounds = 100;
+  bool keeplock = false;
+
+  while ((opt = getopt (argc, argv, "n:r:k")) != -1)
+    switch (opt)
+      {
+      case 'n':
+	nthreads = atol (optarg);
+	break;
+      case 'r':
+	nrounds = atol (optarg);
+	break;
+      case 'k':
+	keeplock = true;
+	break;
+      }
+
+  ntogo = nthreads;
+
+  pthread_t th[nthreads];
+  int i;
+  for (i = 0; __builtin_expect (i < nthreads, 1); ++i)
+    if (__glibc_unlikely ((err = pthread_create (&th[i], NULL, cons, (void *) (long) i)) != 0))
+      printf ("pthread_create: %s\n", strerror (err));
+
+  for (i = 0; __builtin_expect (i < nrounds, 1); ++i)
+    {
+      pthread_mutex_lock (&mut2);
+      while (! alldone)
+	pthread_cond_wait (&cond2, &mut2);
+      pthread_mutex_unlock (&mut2);
+
+      pthread_mutex_lock (&mut1);
+      if (! keeplock)
+	pthread_mutex_unlock (&mut1);
+
+      ntogo = nthreads;
+      alldone = false;
+      if (i + 1 >= nrounds)
+	last_round = true;
+
+      pthread_cond_broadcast (&cond1);
+
+      if (keeplock)
+	pthread_mutex_unlock (&mut1);
+    }
+
+  for (i = 0; i < nthreads; ++i)
+    if ((err = pthread_join (th[i], NULL)) != 0)
+      printf ("pthread_create: %s\n", strerror (err));
+
+  return 0;
+}