xref: /onnv-gate/usr/src/cmd/dtrace/test/tst/common/buffering/tst.ring3.d (revision 2633:71bab08d24b2)
1*2633Sahl /*
2*2633Sahl  * CDDL HEADER START
3*2633Sahl  *
4*2633Sahl  * The contents of this file are subject to the terms of the
5*2633Sahl  * Common Development and Distribution License (the "License").
6*2633Sahl  * You may not use this file except in compliance with the License.
7*2633Sahl  *
8*2633Sahl  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9*2633Sahl  * or http://www.opensolaris.org/os/licensing.
10*2633Sahl  * See the License for the specific language governing permissions
11*2633Sahl  * and limitations under the License.
12*2633Sahl  *
13*2633Sahl  * When distributing Covered Code, include this CDDL HEADER in each
14*2633Sahl  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15*2633Sahl  * If applicable, add the following below this CDDL HEADER, with the
16*2633Sahl  * fields enclosed by brackets "[]" replaced with your own identifying
17*2633Sahl  * information: Portions Copyright [yyyy] [name of copyright owner]
18*2633Sahl  *
19*2633Sahl  * CDDL HEADER END
20*2633Sahl  */
21*2633Sahl 
22*2633Sahl /*
23*2633Sahl  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
24*2633Sahl  * Use is subject to license terms.
25*2633Sahl  */
26*2633Sahl 
27*2633Sahl #pragma ident	"%Z%%M%	%I%	%E% SMI"
28*2633Sahl 
29*2633Sahl /*
30*2633Sahl  * ASSERTION:
31*2633Sahl  *   Positive test for ring buffer policy.
32*2633Sahl  *
33*2633Sahl  * SECTION: Buffers and Buffering/ring Policy;
34*2633Sahl  *	Buffers and Buffering/Buffer Sizes;
35*2633Sahl  *	Options and Tunables/bufsize;
36*2633Sahl  *	Options and Tunables/bufpolicy
37*2633Sahl  */
38*2633Sahl 
39*2633Sahl /*
40*2633Sahl  * We make some regrettable assumptions about the implementation in this test.
41*2633Sahl  * First, we assume that each entry for the printf() of an int takes _exactly_
42*2633Sahl  * eight bytes (four bytes for the EPID, four bytes for the payload).  Second,
43*2633Sahl  * we assume that by allocating storage for n + 1 records, we will get exactly
44*2633Sahl  * n.  Here is why:  the final predicate that evaluates to false will reserve
45*2633Sahl  * space that it won't use.  This act of reservation will advance the wrapped
46*2633Sahl  * offset.  That record won't be subsequently used, but the wrapped offset has
47*2633Sahl  * advanced.  (And in this case, that old record is clobbered by the exit()
48*2633Sahl  * anyway.)  Thirdly:  we rely on t_cpu/cpu_id.  Finally:  we rely on being
49*2633Sahl  * able to run on the CPU that we first ran on.
50*2633Sahl  */
51*2633Sahl #pragma D option bufpolicy=ring
52*2633Sahl #pragma D option bufsize=40
53*2633Sahl #pragma D option quiet
54*2633Sahl 
55*2633Sahl int n;
56*2633Sahl 
57*2633Sahl BEGIN
58*2633Sahl {
59*2633Sahl 	cpuid = -1;
60*2633Sahl }
61*2633Sahl 
62*2633Sahl tick-10msec
63*2633Sahl /cpuid == -1/
64*2633Sahl {
65*2633Sahl 	cpuid = curthread->t_cpu->cpu_id;
66*2633Sahl }
67*2633Sahl 
68*2633Sahl tick-10msec
69*2633Sahl /curthread->t_cpu->cpu_id == cpuid && n < 100/
70*2633Sahl {
71*2633Sahl 	printf("%d\n", n++);
72*2633Sahl }
73*2633Sahl 
74*2633Sahl tick-10msec
75*2633Sahl /n == 100/
76*2633Sahl {
77*2633Sahl 	exit(0);
78*2633Sahl }
79