commit 038dad7ef29b0b724071edb5f8cc7a9845584454
author Damjan Marion <damarion@cisco.com> Fri Jan 19 21:19:57 2024 +0100
committer Florin Coras <florin.coras@gmail.com> Sat Jan 20 18:28:09 2024 +0000
tree fd49f72aa41a215b73be0409dc1f512e1f82bef2
parent 5840c66bbc15b265e280997b028442f9fedd92f6

buffers: add compile-time option to set buffer alignment

Type: improvement
Change-Id: I88c4c45bed0bdd8686e17e4f77a7d32a08c995aa
Signed-off-by: Damjan Marion <damarion@cisco.com>

src/vlib/CMakeLists.txt

diff --git a/src/vlib/CMakeLists.txt b/src/vlib/CMakeLists.txt
index 76de4ed..9c41216 100644
--- a/src/vlib/CMakeLists.txt
+++ b/src/vlib/CMakeLists.txt
@@ -22,6 +22,12 @@
   set(BUFFER_ALLOC_FAULT_INJECTOR 0 CACHE STRING "fault injector off")
 endif()
 
+if(VPP_PLATFORM_BUFFER_ALIGN)
+  set(VLIB_BUFFER_ALIGN ${VPP_PLATFORM_BUFFER_ALIGN})
+else()
+  set(VLIB_BUFFER_ALIGN ${VPP_CACHE_LINE_SIZE})
+endif()
+
 set(PRE_DATA_SIZE 128 CACHE STRING "Buffer headroom size.")
 
 if (CMAKE_BUILD_TYPE_UC STREQUAL "DEBUG")

src/vlib/buffer.c

diff --git a/src/vlib/buffer.c b/src/vlib/buffer.c
index 005326d..82fe641 100644
--- a/src/vlib/buffer.c
+++ b/src/vlib/buffer.c
@@ -471,11 +471,7 @@
 vlib_buffer_alloc_size (uword ext_hdr_size, uword data_size)
 {
   uword alloc_size = ext_hdr_size + sizeof (vlib_buffer_t) + data_size;
-  alloc_size = CLIB_CACHE_LINE_ROUND (alloc_size);
-
-  /* in case when we have even number of cachelines, we add one more for
-   * better cache occupancy */
-  alloc_size |= CLIB_CACHE_LINE_BYTES;
+  alloc_size = round_pow2 (alloc_size, VLIB_BUFFER_ALIGN);
 
   return alloc_size;
 }

src/vlib/buffer.h

diff --git a/src/vlib/buffer.h b/src/vlib/buffer.h
index a747ea9..7d45689 100644
--- a/src/vlib/buffer.h
+++ b/src/vlib/buffer.h
@@ -47,8 +47,7 @@
 #include <vppinfra/lock.h>
 #include <vlib/error.h>		/* for vlib_error_t */
 
-#include <vlib/config.h>	/* for __PRE_DATA_SIZE */
-#define VLIB_BUFFER_PRE_DATA_SIZE	__PRE_DATA_SIZE
+#include <vlib/config.h> /* for VLIB_BUFFER_PRE_DATA_SIZE */
 
 #define VLIB_BUFFER_DEFAULT_DATA_SIZE (2048)
 

src/vlib/config.h.in

diff --git a/src/vlib/config.h.in b/src/vlib/config.h.in
index 19ec10c..b233b32 100644
--- a/src/vlib/config.h.in
+++ b/src/vlib/config.h.in
@@ -16,7 +16,8 @@
 #ifndef included_vlib_config_h
 #define included_vlib_config_h
 
-#define __PRE_DATA_SIZE @PRE_DATA_SIZE@
+#define VLIB_BUFFER_PRE_DATA_SIZE @PRE_DATA_SIZE@
+#define VLIB_BUFFER_ALIGN @VLIB_BUFFER_ALIGN@
 #define VLIB_BUFFER_ALLOC_FAULT_INJECTOR @BUFFER_ALLOC_FAULT_INJECTOR@
 #define VLIB_PROCESS_LOG2_STACK_SIZE @VLIB_PROCESS_LOG2_STACK_SIZE@