On Tue, 9 Sep 2025 07:40:23 +0200 Thierry Herbelot <thierry.herbe...@6wind.com> wrote:
> The qede PMD stopped working under Ubuntu-24.04 (using gcc-13) when > compiled with -O3 (default level for all DPDK code). A bug is opened > for this issue (see Link). The same issue is also seen with gcc-12 > and gcc-14. The issue is not seen with clang-20. > > A first workaround is to just disable all optimizations (-O0), which > restores packet Rx with Qlogic NICs. However, the performance impact > is not acceptable (around 50% drop). > > A better compromise is to use -O1 for the qede PMD: > - there is some perf impact, > - but the PMD is working as expected (packets are correctly received). > > When compiling with both -O2 and -O3 and gcc > 11, there is no packet > reception when using the qede PMD. The root cause could be missing > 'volatile' keywords or missing memory barriers in the qede PMD code. > > Link: https://bugs.dpdk.org/show_bug.cgi?id=1379 > Signed-off-by: Thierry Herbelot <thierry.herbe...@6wind.com> Which rx_burst gets used on that hardware? Is there any indication of errors (like rx_mbuf_alloc_failed) in the stats. The driver does not appear to have any write barrier after updating the consumed packets. Would this help? diff --git a/drivers/net/qede/qede_rxtx.c b/drivers/net/qede/qede_rxtx.c index 25e28fd9f6..1b5109d966 100644 --- a/drivers/net/qede/qede_rxtx.c +++ b/drivers/net/qede/qede_rxtx.c @@ -1295,6 +1295,8 @@ static inline void qede_rx_bd_ring_consume(struct qede_rx_queue *rxq) { ecore_chain_consume(&rxq->rx_bd_ring); rxq->sw_rx_cons++; + + rte_wmb(); }
