* Reorder the fields in the mbuf so that we have fields that are used
together side-by-side in the structure. This means that we have a
contiguous block of 8-bytes in the mbuf which are used to reset an mbuf
of descriptor rearm.
* Where needed add in a dummy fields to overwrite values 8 or 16 bytes
at a time, when doing RX or RX descriptor rearm. This avoids compiler
warnings when using uint64_t values to overwrite a set of smaller
values.
* At the end, place fields that are only used for TX or for the slower
RX path, and mark them as down to be moved to a second cache line.
Signed-off-by: Bruce Richardson <bruce.richardson at intel.com>
---
lib/librte_mbuf/rte_mbuf.c | 2 +-
lib/librte_mbuf/rte_mbuf.h | 37 +++++++++++++++++++++----------------
2 files changed, 22 insertions(+), 17 deletions(-)
diff --git a/lib/librte_mbuf/rte_mbuf.c b/lib/librte_mbuf/rte_mbuf.c
index 64f1587..594b910 100644
--- a/lib/librte_mbuf/rte_mbuf.c
+++ b/lib/librte_mbuf/rte_mbuf.c
@@ -161,7 +161,7 @@ rte_pktmbuf_dump(FILE *f, const struct rte_mbuf *m,
unsigned dump_len)
fprintf(f, "dump mbuf at 0x%p, phys=%"PRIx64", buf_len=%u\n",
m, (uint64_t)m->buf_physaddr, (unsigned)m->buf_len);
- fprintf(f, " pkt_len=%"PRIu32", ol_flags=%"PRIx16", nb_segs=%u, "
+ fprintf(f, " pkt_len=%"PRIu32", ol_flags=%"PRIx64", nb_segs=%u, "
"in_port=%u\n", m->pkt_len, m->ol_flags,
(unsigned)m->nb_segs, (unsigned)m->port);
nb_segs = m->nb_segs;
diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h
index e0981c9..566bb7e 100644
--- a/lib/librte_mbuf/rte_mbuf.h
+++ b/lib/librte_mbuf/rte_mbuf.h
@@ -132,22 +132,20 @@ union rte_vlan_macip {
/**< MAC+IP length. */
#define TX_MACIP_LEN_CMP_MASK (TX_MAC_LEN_CMP_MASK | TX_IP_LEN_CMP_MASK)
+
/**
* The generic rte_mbuf, containing a packet mbuf.
*/
struct rte_mbuf {
- struct rte_mempool *pool; /**< Pool from which mbuf was allocated. */
void *buf_addr; /**< Virtual address of segment buffer. */
phys_addr_t buf_physaddr; /**< Physical address of segment buffer. */
- uint16_t buf_len; /**< Length of segment buffer. */
- /* valid for any segment */
- struct rte_mbuf *next; /**< Next segment of scattered packet. */
+ /* next 8 bytes are initialised on RX descriptor rearm */
+ uint64_t rearm_data[0]; /**< dummy element so we can get uin64_t ptrs
+ * to this part of the mbuf without alias error
+ */
+ uint16_t buf_len; /**< Length of segment buffer. */
uint16_t data_off;
- uint16_t data_len; /**< Amount of data in segment buffer. */
- uint32_t pkt_len; /**< Total pkt len: sum of all segments. */
-
-#ifdef RTE_MBUF_REFCNT
/**
* 16-bit Reference counter.
* It should only be accessed using the following functions:
@@ -157,20 +155,23 @@ struct rte_mbuf {
* config option.
*/
union {
+#ifdef RTE_MBUF_REFCNT
rte_atomic16_t refcnt_atomic; /**< Atomically accessed refcnt
*/
uint16_t refcnt; /**< Non-atomically accessed
refcnt */
- };
-#else
- uint16_t refcnt_reserved; /**< Do not use this field */
#endif
-
- /* these fields are valid for first segment only */
+ uint16_t refcnt_reserved; /**< Do not use this field */
+ };
uint8_t nb_segs; /**< Number of segments. */
uint8_t port; /**< Input port. */
- uint16_t ol_flags; /**< Offload features. */
- uint16_t reserved; /**< Unused field. Required for padding.
*/
- /* offload features, valid for first segment only */
+ /* remaining bytes are set on RX when pulling packet from descriptor */
+ uint64_t ol_flags; /**< Offload features. */
+
+ __m128i rx_descriptor_fields1[0]; /**< dummy field used as marker for
+ * writes in a vector driver */
+ uint16_t packet_type; /**< Type of packet, e.g. protocols used */
+ uint16_t data_len; /**< Amount of data in segment buffer. */
+ uint32_t pkt_len; /**< Total pkt len: sum of all segments. */
union rte_vlan_macip vlan_macip;
union {
uint32_t rss; /**< RSS hash result if RSS enabled */
@@ -181,6 +182,10 @@ struct rte_mbuf {
uint32_t sched; /**< Hierarchical scheduler */
} hash; /**< hash information */
+ /* second cache line, fields only used in slow path or on TX */
+ struct rte_mempool *pool; /**< Pool from which mbuf was allocated. */
+ struct rte_mbuf *next; /**< Next segment of scattered packet. */
+
union {
uint8_t metadata[0];
uint16_t metadata16[0];
--
1.9.3
