On 2/23/2022 12:19 PM, Michal Krawczyk wrote:
As the default behavior for arm64 is to alias rte_memcpy as memcpy, ENA
cannot redefine memcpy as rte_memcpy as it would cause nested
declaration.
To make it possible to use optimized memcpy in the ena_com layer on Arm,
Out of curiosity, do you have any performance measurements for
the optimized memcpy usage?
the driver now redefines memcpy when it is beneficial:
* For arm64 only when the flag RTE_ARCH_ARM64_MEMCPY was defined
* For arm only when the flag RTE_ARCH_ARM_NEON_MEMCPY was defined
Signed-off-by: Michal Krawczyk <m...@semihalf.com>
Reviewed-by: Dawid Gorecki <d...@semihalf.com>
Reviewed-by: Shai Brandes <shaib...@amazon.com>
---
doc/guides/rel_notes/release_22_03.rst | 1 +
drivers/net/ena/base/ena_plat_dpdk.h | 7 +++++--
2 files changed, 6 insertions(+), 2 deletions(-)
diff --git a/doc/guides/rel_notes/release_22_03.rst
b/doc/guides/rel_notes/release_22_03.rst
index c8e38d4c70..92490afd60 100644
--- a/doc/guides/rel_notes/release_22_03.rst
+++ b/doc/guides/rel_notes/release_22_03.rst
@@ -112,6 +112,7 @@ New Features
* Added new checksum related xstats: ``l3_csum_bad``, ``l4_csum_bad`` and
``l4_csum_good``.
* Added support for the link status configuration.
+ * Added optimized memcpy support for the ARM platforms.
* **Updated Cisco enic driver.**
diff --git a/drivers/net/ena/base/ena_plat_dpdk.h b/drivers/net/ena/base/ena_plat_dpdk.h
index 4e7f52881a..41db883c63 100644
--- a/drivers/net/ena/base/ena_plat_dpdk.h
+++ b/drivers/net/ena/base/ena_plat_dpdk.h
@@ -66,8 +66,11 @@ typedef uint64_t dma_addr_t;
#define ENA_UDELAY(x) rte_delay_us_block(x)
#define ENA_TOUCH(x) ((void)(x))
-/* Avoid nested declaration on arm64, as it may define rte_memcpy as memcpy. */
-#if defined(RTE_ARCH_X86)
+/* Redefine memcpy with caution: rte_memcpy can be simply aliased to memcpy, so
+ * make the redefinition only if it's safe (and beneficial) to do so.
+ */
+#if defined(RTE_ARCH_X86) || defined(RTE_ARCH_ARM64_MEMCPY) || \
+ defined(RTE_ARCH_ARM_NEON_MEMCPY)
#undef memcpy
#define memcpy rte_memcpy
#endif
I can see there is 'ena_plat_dpdk.h', which seems like an osdep header,
it is possible to use 'ena_memcpy' in the code and in the 'ena_plat_dpdk.h'
define it as:
#define ena_memcpy rte_memcpy
This is just for your information if it helps, usage is up to you.
