Replace DTrace sample with a premissive license

samples/DTrace/trace_futexes.d

@@ -0,0 +1,184 @@
+#!/usr/sbin/dtrace -qs
+
+// Source: https://github.com/bycn82/freebsd/blob/12a4a4a008eac3cfa71e496b33eaeaf426c374c1/sys/compat/linux/trace_futexes.d
+
+/*-
+ * Copyright (c) 2011-2012 Alexander Leidinger <netchild@FreeBSD.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer
+ *    in this position and unchanged.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+/**
+ * Trace futex operations:
+ *  - internal locks
+ *  - size of the futex list
+ *  - report error conditions (emulation errors, kernel errors,
+ *    programming errors)
+ *  - execution time (wallclock) of futex related functions
+ */
+
+#pragma D option specsize=32m
+
+/* Error conditions */
+linuxulator*:futex:futex_get:error,
+linuxulator*:futex:futex_sleep:requeue_error,
+linuxulator*:futex:futex_sleep:sleep_error,
+linuxulator*:futex:futex_wait:copyin_error,
+linuxulator*:futex:futex_wait:itimerfix_error,
+linuxulator*:futex:futex_wait:sleep_error,
+linuxulator*:futex:futex_atomic_op:missing_access_check,
+linuxulator*:futex:futex_atomic_op:unimplemented_op,
+linuxulator*:futex:futex_atomic_op:unimplemented_cmp,
+linuxulator*:futex:linux_sys_futex:unimplemented_clockswitch,
+linuxulator*:futex:linux_sys_futex:copyin_error,
+linuxulator*:futex:linux_sys_futex:unhandled_efault,
+linuxulator*:futex:linux_sys_futex:unimplemented_lock_pi,
+linuxulator*:futex:linux_sys_futex:unimplemented_unlock_pi,
+linuxulator*:futex:linux_sys_futex:unimplemented_trylock_pi,
+linuxulator*:futex:linux_sys_futex:unimplemented_wait_requeue_pi,
+linuxulator*:futex:linux_sys_futex:unimplemented_cmp_requeue_pi,
+linuxulator*:futex:linux_sys_futex:unknown_operation,
+linuxulator*:futex:linux_get_robust_list:copyout_error,
+linuxulator*:futex:handle_futex_death:copyin_error,
+linuxulator*:futex:fetch_robust_entry:copyin_error,
+linuxulator*:futex:release_futexes:copyin_error
+{
+  printf("ERROR: %s in %s:%s:%s\n", probename, probeprov, probemod,
+      probefunc);
+  stack();
+  ustack();
+}
+
+linuxulator*:futex:linux_sys_futex:invalid_cmp_requeue_use,
+linuxulator*:futex:linux_sys_futex:deprecated_requeue,
+linuxulator*:futex:linux_set_robust_list:size_error
+{
+  printf("WARNING: %s:%s:%s:%s in application %s, maybe an application error?\n",
+      probename, probeprov, probemod, probefunc, execname);
+  stack();
+  ustack();
+}
+
+
+/* Per futex checks/statistics */
+
+linuxulator*:futex:futex:create
+{
+  ++futex_count;
+  @max_futexes = max(futex_count);
+}
+
+linuxulator*:futex:futex:destroy
+/futex_count == 0/
+{
+  printf("ERROR: Request to destroy a futex which was not created,\n");
+  printf("       or this script was started after some futexes where\n");
+  printf("       created. Stack trace:\n");
+  stack();
+  ustack();
+}
+
+linuxulator*:futex:futex:destroy
+{
+  --futex_count;
+}
+
+
+/* Internal locks */
+
+linuxulator*:locks:futex_mtx:locked
+{
+  ++check[probefunc, arg0];
+  @stats[probefunc] = count();
+
+  ts[probefunc] = timestamp;
+  spec[probefunc] = speculation();
+  printf("Stacktrace of last lock operation of the %s:\n", probefunc);
+  stack();
+}
+
+linuxulator*:locks:futex_mtx:unlock
+/check[probefunc, arg0] == 0/
+{
+  printf("ERROR: unlock attempt of unlocked %s (%p),", probefunc, arg0);
+  printf("       missing SDT probe in kernel, or dtrace program started");
+  printf("       while the %s was already held (race condition).", probefunc);
+  printf("       Stack trace follows:");
+  stack();
+}
+
+linuxulator*:locks:futex_mtx:unlock
+{
+  discard(spec[probefunc]);
+  spec[probefunc] = 0;
+  --check[probefunc, arg0];
+}
+
+/* Timeout handling for internal locks */
+
+tick-10s
+/spec["futex_mtx"] != 0 && timestamp - ts["futex_mtx"] >= 9999999000/
+{
+  commit(spec["futex_mtx"]);
+  spec["futex_mtx"] = 0;
+}
+
+
+/* Timing statistings */
+
+linuxulator*:futex::entry
+{
+  self->time[probefunc] = timestamp;
+  @calls[probeprov, execname, probefunc] = count();
+}
+
+linuxulator*:futex::return
+/self->time[probefunc] != 0/
+{
+  this->timediff = self->time[probefunc] - timestamp;
+
+        @timestats[probeprov, execname, probefunc] = quantize(this->timediff);
+        @longest[probeprov, probefunc] = max(this->timediff);
+
+        self->time[probefunc] = 0;
+}
+
+
+/* Statistics */
+
+END
+{
+  printf("Number of locks per type:");
+  printa(@stats);
+  printf("Number of maximum number of futexes in the futex list:");
+  printa(@max_futexes);
+  printf("Number of futexes still existing: %d", futex_count);
+  printf("Number of calls per provider/application/kernel function:");
+  printa(@calls);
+  printf("Wallclock-timing statistics per provider/application/kernel function (in ns):");
+  printa(@timestats);
+  printf("Longest running (wallclock!) functions per provider (in ns):");
+  printa(@longest);
+}