On 19/10/2026 22:10, Konstantin Ananyev wrote:
Document the data plane limitation in the file docstring of
rte_bpf_ethdev.h: packet callback execution expects only one
thread per port/queue pair at a time, making concurrent bursts
(such as with RTE_ETH_TX_OFFLOAD_MT_LOCKFREE, shared RX queues,
or multi-threaded software PMDs) unsupported.
Not sure what do you mean by:
'shared RX queues' and 'multi-threaded software PMDs'. Can you
probably clarify?
I mean any hypothetical solutions that call rx/tx burst concurrently
from multiple threads or processes. To avoid confusion, will just leave
only an RTE_ETH_TX_OFFLOAD_MT_LOCKFREE example in the next version.
diff --git a/lib/bpf/rte_bpf_ethdev.h b/lib/bpf/rte_bpf_ethdev.h
index 686fda8d94..cf3b4048f0 100644
--- a/lib/bpf/rte_bpf_ethdev.h
+++ b/lib/bpf/rte_bpf_ethdev.h
@@ -10,8 +10,12 @@
*
* API to install BPF filter as RX/TX callbacks for eth devices.
* Note that right now:
- * - it is not MT safe, i.e. it is not allowed to do load/unload for
the
- * same port/queue from different threads in parallel.
+ * - in the data plane, it expects only one thread per port/queue
pair at a time.
+ * Calling RX/TX burst functions concurrently on the same queue
(e.g. when using
+ * RTE_ETH_TX_OFFLOAD_MT_LOCKFREE, shared RX queues, or
multi-threaded
+ * software PMDs) is not supported.
+ * - in the control plane, it is not MT safe, i.e. it is not allowed
to do
+ * load/unload for the same port/queue from different threads in
parallel.
AFAIK, all CP ethdev API is not MT-safe.
Not sure there is a reason to put it here again.
If you believe it is, then probably worth to mention that it follows
ethdev CP API convention.
I actually think the CP is safe now due to the spinlock, but I was wary
of removing this pre-existing phrase. Since you support removing it, I
will remove it.
