usr/src/cmd/dtrace/test/tst/common/buffering/tst.ring3.d

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21
  22 /*
  23  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
  24  * Use is subject to license terms.
  25  */
  26 /*
  27  * Copyright (c) 2012 by Delphix. All rights reserved.
  28  */
  29
  30 /*
  31  * ASSERTION:
  32  *   Positive test for ring buffer policy.
  33  *
  34  * SECTION: Buffers and Buffering/ring Policy;
  35  *      Buffers and Buffering/Buffer Sizes;
  36  *      Options and Tunables/bufsize;
  37  *      Options and Tunables/bufpolicy
  38  */
  39
  40 /*
  41  * We make some regrettable assumptions about the implementation in this
  42  * test.  First, we assume that each entry for the printf() of an int
  43  * takes _exactly_ 16 bytes (4 bytes for the EPID, 8 bytes for the
  44  * timestamp, 4 bytes for the payload).  Second, we assume that by
  45  * allocating storage for n + 1 records, we will get exactly n.  Here is
  46  * why:  the final predicate that evaluates to false will reserve space
  47  * that it won't use.  This act of reservation will advance the wrapped
  48  * offset.  That record won't be subsequently used, but the wrapped
  49  * offset has advanced.  (And in this case, that old record is clobbered
  50  * by the exit() anyway.)  Thirdly:  we rely on t_cpu/cpu_id.  Finally:
  51  * we rely on being able to run on the CPU that we first ran on.
  52  */
  53 #pragma D option bufpolicy=ring
  54 #pragma D option bufsize=80
  55 #pragma D option quiet
  56
  57 int n;
  58
  59 BEGIN
  60 {
  61         cpuid = -1;
  62 }
  63
  64 tick-10msec
  65 /cpuid == -1/
  66 {
  67         cpuid = curthread->t_cpu->cpu_id;
  68 }
  69
  70 tick-10msec
  71 /curthread->t_cpu->cpu_id == cpuid && n < 100/
  72 {
  73         printf("%d\n", n++);
  74 }
  75
  76 tick-10msec
  77 /n == 100/
  78 {
  79         exit(0);
  80 }