46 lines
731 B
Plaintext
46 lines
731 B
Plaintext
C IRIW+fencembonceonces+OnceOnce
|
|
|
|
(*
|
|
* Result: Never
|
|
*
|
|
* Test of independent reads from independent writes with smp_mb()
|
|
* between each pairs of reads. In other words, is smp_mb() sufficient to
|
|
* cause two different reading processes to agree on the order of a pair
|
|
* of writes, where each write is to a different variable by a different
|
|
* process? This litmus test exercises LKMM's "propagation" rule.
|
|
*)
|
|
|
|
{}
|
|
|
|
P0(int *x)
|
|
{
|
|
WRITE_ONCE(*x, 1);
|
|
}
|
|
|
|
P1(int *x, int *y)
|
|
{
|
|
int r0;
|
|
int r1;
|
|
|
|
r0 = READ_ONCE(*x);
|
|
smp_mb();
|
|
r1 = READ_ONCE(*y);
|
|
}
|
|
|
|
P2(int *y)
|
|
{
|
|
WRITE_ONCE(*y, 1);
|
|
}
|
|
|
|
P3(int *x, int *y)
|
|
{
|
|
int r0;
|
|
int r1;
|
|
|
|
r0 = READ_ONCE(*y);
|
|
smp_mb();
|
|
r1 = READ_ONCE(*x);
|
|
}
|
|
|
|
exists (1:r0=1 /\ 1:r1=0 /\ 3:r0=1 /\ 3:r1=0)
|