xref: /illumos-gate/usr/src/cmd/dtrace/test/tst/common/buffering/tst.ring3.d (revision 3d393ee6c37fa10ac512ed6d36109ad616dc7c1a)
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 #pragma ident	"%Z%%M%	%I%	%E% SMI"
28 
29 /*
30  * ASSERTION:
31  *   Positive test for ring buffer policy.
32  *
33  * SECTION: Buffers and Buffering/ring Policy;
34  *	Buffers and Buffering/Buffer Sizes;
35  *	Options and Tunables/bufsize;
36  *	Options and Tunables/bufpolicy
37  */
38 
39 /*
40  * We make some regrettable assumptions about the implementation in this test.
41  * First, we assume that each entry for the printf() of an int takes _exactly_
42  * eight bytes (four bytes for the EPID, four bytes for the payload).  Second,
43  * we assume that by allocating storage for n + 1 records, we will get exactly
44  * n.  Here is why:  the final predicate that evaluates to false will reserve
45  * space that it won't use.  This act of reservation will advance the wrapped
46  * offset.  That record won't be subsequently used, but the wrapped offset has
47  * advanced.  (And in this case, that old record is clobbered by the exit()
48  * anyway.)  Thirdly:  we rely on t_cpu/cpu_id.  Finally:  we rely on being
49  * able to run on the CPU that we first ran on.
50  */
51 #pragma D option bufpolicy=ring
52 #pragma D option bufsize=40
53 #pragma D option quiet
54 
55 int n;
56 
57 BEGIN
58 {
59 	cpuid = -1;
60 }
61 
62 tick-10msec
63 /cpuid == -1/
64 {
65 	cpuid = curthread->t_cpu->cpu_id;
66 }
67 
68 tick-10msec
69 /curthread->t_cpu->cpu_id == cpuid && n < 100/
70 {
71 	printf("%d\n", n++);
72 }
73 
74 tick-10msec
75 /n == 100/
76 {
77 	exit(0);
78 }
79