event/octeontx2: add devargs to control timer adapters

[dpdk.git] / doc / guides / prog_guide / env_abstraction_layer.rst

diff --git a/doc/guides/prog_guide/env_abstraction_layer.rst b/doc/guides/prog_guide/env_abstraction_layer.rst
index 6a04c3c..f15bcd9 100644 (file)
--- a/doc/guides/prog_guide/env_abstraction_layer.rst
+++ b/doc/guides/prog_guide/env_abstraction_layer.rst
@@ -147,6 +147,14 @@ A default validator callback is provided by EAL, which can be enabled with a
 ``--socket-limit`` command-line option, for a simple way to limit maximum amount
 of memory that can be used by DPDK application.
 
+.. warning::
+    Memory subsystem uses DPDK IPC internally, so memory allocations/callbacks
+    and IPC must not be mixed: it is not safe to allocate/free memory inside
+    memory-related or IPC callbacks, and it is not safe to use IPC inside
+    memory-related callbacks. See chapter
+    :ref:`Multi-process Support <Multi-process_Support>` for more details about
+    DPDK IPC.
+
 + Legacy memory mode
 
 This mode is enabled by specifying ``--legacy-mem`` command-line switch to the
@@ -581,6 +589,16 @@ Known Issues
 
   5. It MUST not be used by multi-producer/consumer pthreads, whose scheduling policies are SCHED_FIFO or SCHED_RR.
 
+  Alternatively, applications can use the lock-free stack mempool handler. When
+  considering this handler, note that:
+
+  - It is currently limited to the x86_64 platform, because it uses an
+    instruction (16-byte compare-and-swap) that is not yet available on other
+    platforms.
+  - It has worse average-case performance than the non-preemptive rte_ring, but
+    software caching (e.g. the mempool cache) can mitigate this by reducing the
+    number of stack accesses.
+
 + rte_timer
 
   Running  ``rte_timer_manage()`` on a non-EAL pthread is not allowed. However, resetting/stopping the timer from a non-EAL pthread is allowed.
@@ -723,7 +741,7 @@ The most important fields in the structure and how they are used are described b
 
 Malloc heap is a doubly-linked list, where each element keeps track of its
 previous and next elements. Due to the fact that hugepage memory can come and
-go, neighbouring malloc elements may not necessarily be adjacent in memory.
+go, neighboring malloc elements may not necessarily be adjacent in memory.
 Also, since a malloc element may span multiple pages, its contents may not
 necessarily be IOVA-contiguous either - each malloc element is only guaranteed
 to be virtually contiguous.