On Thu, 23 Jul 2020 12:02:40 +0500
Sarosh Arif <sarosh.a...@emumba.com> wrote:
> Since rte_memcpy is more optimized it should be used instead of memcpy
>
> Signed-off-by: Sarosh Arif <sarosh.a...@emumba.com>
The part in pkmbuf_pool_init is not performance critical.
The layout of rte_mbuf_dynfield is sub optimal.
struct rte_mbuf_dynfield {
char name[64]; /* 0 64 */
/* --- cacheline 1 boundary (64 bytes) --- */
size_t size; /* 64 8 */
size_t align; /* 72 8 */
unsigned int flags; /* 80 4 */
/* size: 88, cachelines: 2, members: 4 */
/* padding: 4 */
/* last cacheline: 24 bytes */
};
1. It should have been sized so that overall it was 64 bytes.
2. Use 8 bytes for size and align is wasteful.
3. Hold 4 bytes for future flags is also wasteful. YAGNI
If you look at assembly output on x86 the copy of params becomes a sequence
of vmovups instructions with Gcc.
For 20.11 maybe:
diff --git a/lib/librte_mbuf/rte_mbuf_dyn.h b/lib/librte_mbuf/rte_mbuf_dyn.h
index 8407230ecfdc..eb1d01f97f40 100644
--- a/lib/librte_mbuf/rte_mbuf_dyn.h
+++ b/lib/librte_mbuf/rte_mbuf_dyn.h
@@ -70,16 +70,16 @@
/**
* Maximum length of the dynamic field or flag string.
*/
-#define RTE_MBUF_DYN_NAMESIZE 64
+#define RTE_MBUF_DYN_NAMESIZE 60
/**
* Structure describing the parameters of a mbuf dynamic field.
*/
struct rte_mbuf_dynfield {
char name[RTE_MBUF_DYN_NAMESIZE]; /**< Name of the field. */
- size_t size; /**< The number of bytes to reserve. */
- size_t align; /**< The alignment constraint (power of 2). */
- unsigned int flags; /**< Reserved for future use, must be 0. */
+ uint8_t size; /**< The number of bytes to reserve. */
+ uint8_t align; /**< The alignment constraint (power of 2). */
+ uint16_t flags; /**< Reserved for future use, must be 0. */
};
/**
Or make the dynamic field dynamic size to avoid wasting space?
