1This directory contains the following litmus tests:
2
3CoRR+poonceonce+Once.litmus
4 Test of read-read coherence, that is, whether or not two
5 successive reads from the same variable are ordered.
6
7CoRW+poonceonce+Once.litmus
8 Test of read-write coherence, that is, whether or not a read
9 from a given variable followed by a write to that same variable
10 are ordered.
11
12CoWR+poonceonce+Once.litmus
13 Test of write-read coherence, that is, whether or not a write
14 to a given variable followed by a read from that same variable
15 are ordered.
16
17CoWW+poonceonce.litmus
18 Test of write-write coherence, that is, whether or not two
19 successive writes to the same variable are ordered.
20
21IRIW+fencembonceonces+OnceOnce.litmus
22 Test of independent reads from independent writes with smp_mb()
23 between each pairs of reads. In other words, is smp_mb()
24 sufficient to cause two different reading processes to agree on
25 the order of a pair of writes, where each write is to a different
26 variable by a different process? This litmus test is forbidden
27 by LKMM's propagation rule.
28
29IRIW+poonceonces+OnceOnce.litmus
30 Test of independent reads from independent writes with nothing
31 between each pairs of reads. In other words, is anything at all
32 needed to cause two different reading processes to agree on the
33 order of a pair of writes, where each write is to a different
34 variable by a different process?
35
36ISA2+pooncelock+pooncelock+pombonce.litmus
37 Tests whether the ordering provided by a lock-protected S
38 litmus test is visible to an external process whose accesses are
39 separated by smp_mb(). This addition of an external process to
40 S is otherwise known as ISA2.
41
42ISA2+poonceonces.litmus
43 As below, but with store-release replaced with WRITE_ONCE()
44 and load-acquire replaced with READ_ONCE().
45
46ISA2+pooncerelease+poacquirerelease+poacquireonce.litmus
47 Can a release-acquire chain order a prior store against
48 a later load?
49
50LB+fencembonceonce+ctrlonceonce.litmus
51 Does a control dependency and an smp_mb() suffice for the
52 load-buffering litmus test, where each process reads from one
53 of two variables then writes to the other?
54
55LB+poacquireonce+pooncerelease.litmus
56 Does a release-acquire pair suffice for the load-buffering
57 litmus test, where each process reads from one of two variables then
58 writes to the other?
59
60LB+poonceonces.litmus
61 As above, but with store-release replaced with WRITE_ONCE()
62 and load-acquire replaced with READ_ONCE().
63
64MP+onceassign+derefonce.litmus
65 As below, but with rcu_assign_pointer() and an rcu_dereference().
66
67MP+polockmbonce+poacquiresilsil.litmus
68 Protect the access with a lock and an smp_mb__after_spinlock()
69 in one process, and use an acquire load followed by a pair of
70 spin_is_locked() calls in the other process.
71
72MP+polockonce+poacquiresilsil.litmus
73 Protect the access with a lock in one process, and use an
74 acquire load followed by a pair of spin_is_locked() calls
75 in the other process.
76
77MP+polocks.litmus
78 As below, but with the second access of the writer process
79 and the first access of reader process protected by a lock.
80
81MP+poonceonces.litmus
82 As below, but without the smp_rmb() and smp_wmb().
83
84MP+pooncerelease+poacquireonce.litmus
85 As below, but with a release-acquire chain.
86
87MP+porevlocks.litmus
88 As below, but with the first access of the writer process
89 and the second access of reader process protected by a lock.
90
91MP+fencewmbonceonce+fencermbonceonce.litmus
92 Does a smp_wmb() (between the stores) and an smp_rmb() (between
93 the loads) suffice for the message-passing litmus test, where one
94 process writes data and then a flag, and the other process reads
95 the flag and then the data. (This is similar to the ISA2 tests,
96 but with two processes instead of three.)
97
98R+fencembonceonces.litmus
99 This is the fully ordered (via smp_mb()) version of one of
100 the classic counterintuitive litmus tests that illustrates the
101 effects of store propagation delays.
102
103R+poonceonces.litmus
104 As above, but without the smp_mb() invocations.
105
106SB+fencembonceonces.litmus
107 This is the fully ordered (again, via smp_mb() version of store
108 buffering, which forms the core of Dekker's mutual-exclusion
109 algorithm.
110
111SB+poonceonces.litmus
112 As above, but without the smp_mb() invocations.
113
114SB+rfionceonce-poonceonces.litmus
115 This litmus test demonstrates that LKMM is not fully multicopy
116 atomic. (Neither is it other multicopy atomic.) This litmus test
117 also demonstrates the "locations" debugging aid, which designates
118 additional registers and locations to be printed out in the dump
119 of final states in the herd7 output. Without the "locations"
120 statement, only those registers and locations mentioned in the
121 "exists" clause will be printed.
122
123S+poonceonces.litmus
124 As below, but without the smp_wmb() and acquire load.
125
126S+fencewmbonceonce+poacquireonce.litmus
127 Can a smp_wmb(), instead of a release, and an acquire order
128 a prior store against a subsequent store?
129
130WRC+poonceonces+Once.litmus
131WRC+pooncerelease+fencermbonceonce+Once.litmus
132 These two are members of an extension of the MP litmus-test
133 class in which the first write is moved to a separate process.
134 The second is forbidden because smp_store_release() is
135 A-cumulative in LKMM.
136
137Z6.0+pooncelock+pooncelock+pombonce.litmus
138 Is the ordering provided by a spin_unlock() and a subsequent
139 spin_lock() sufficient to make ordering apparent to accesses
140 by a process not holding the lock?
141
142Z6.0+pooncelock+poonceLock+pombonce.litmus
143 As above, but with smp_mb__after_spinlock() immediately
144 following the spin_lock().
145
146Z6.0+pooncerelease+poacquirerelease+fencembonceonce.litmus
147 Is the ordering provided by a release-acquire chain sufficient
148 to make ordering apparent to accesses by a process that does
149 not participate in that release-acquire chain?
150
151A great many more litmus tests are available here:
152
153 https://github.com/paulmckrcu/litmus
154
