Hello all, I am aware that this is some caching/synchronization problem but for some reason despite using the barrier macros it does not seem to go away.What makes it go away though is to give a rte_delay of 100us and re-reading the value again like so: cons_rx_buf = &rxr->rx_buf_ring[cons]; mbuf = cons_rx_buf->mbuf; rte_smp_mb(); if (mbuf == NULL) { int cnt = 0; RTE_LOG(ERR, PMD, "mbuf = NULL cons = %d\n", cons); do { rte_delay_us(100); cons_rx_buf = &rxr->rx_buf_ring[cons]; mbuf = cons_rx_buf->mbuf; } while(mbuf == NULL && ++cnt <= 10); RTE_LOG(ERR, PMD, "mbuf = %p cnt = %d\n", mbuf, cnt); }
Invariably i see the 'mbuf = NULL' print and then post 1 iteration of the while loop the 'mbuf' is not NULL (correct value as expected) and it moves on smoothly....Clearly this seems like some cache synchronization issue and i thought the smp_wb() primitives should have solved it? Any other better ways to fix this other than this rte_delay_us() ? ThanksSmith