Hi.
I am running a server which essentially does the following operations in a loop:
A[i].value = counter; //It's actually something else
asm volatile ("" : : : "memory");
asm volatile("mfence" ::: "memory");
A[i].counter = counter;
printf("%d %d\n", A[i].value, A[i].counter);
counter ++;
Basically, I want a fresh value of A[i].counter to indicate a fresh A[i].value.
I have a remote client which reads the struct A[i] from the server
(via RDMA) in a loop. Sometimes in the value that the client reads,
A[i].counter is larger than A[i].value. i.e., I see the newer value of
A[i].counter but A[i].value corresponds to a previous iteration of the
server's loop.
How can this happen in the presence of memory barriers? With barriers,
A[i].counter should be updated later and therefore should always be
smaller than A[i].value.
Thanks for your help!
Anuj Kalia,
Carnegie Mellon University
--
To unsubscribe from this list: send the line "unsubscribe linux-rdma" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
