Move the next pointer to the first cacheline of the rte_mbuf structure
and move the offload values to the second cacheline to give better
performance to applications using chained mbufs.
Enabled by a configuration option CONFIG_RTE_MBUF_CHAIN_FRIENDLY default
is set to No.
Signed-off-by: Keith Wiles <keith.wiles at intel.com>
---
config/common_base | 2 +
.../linuxapp/eal/include/exec-env/rte_kni_common.h | 8 +++
lib/librte_mbuf/rte_mbuf.h | 67 +++++++++++++++-------
3 files changed, 56 insertions(+), 21 deletions(-)
diff --git a/config/common_base b/config/common_base
index 379a791..f7c624e 100644
--- a/config/common_base
+++ b/config/common_base
@@ -405,6 +405,8 @@ CONFIG_RTE_LIBRTE_MBUF_DEBUG=n
CONFIG_RTE_MBUF_DEFAULT_MEMPOOL_OPS="ring_mp_mc"
CONFIG_RTE_MBUF_REFCNT_ATOMIC=y
CONFIG_RTE_PKTMBUF_HEADROOM=128
+# Set to y if needing to be mbuf chain friendly.
+CONFIG_RTE_MBUF_CHAIN_FRIENDLY=n
#
# Compile librte_timer
diff --git a/lib/librte_eal/linuxapp/eal/include/exec-env/rte_kni_common.h
b/lib/librte_eal/linuxapp/eal/include/exec-env/rte_kni_common.h
index 2acdfd9..44d65cd 100644
--- a/lib/librte_eal/linuxapp/eal/include/exec-env/rte_kni_common.h
+++ b/lib/librte_eal/linuxapp/eal/include/exec-env/rte_kni_common.h
@@ -120,11 +120,19 @@ struct rte_kni_mbuf {
char pad2[4];
uint32_t pkt_len; /**< Total pkt len: sum of all segment
data_len. */
uint16_t data_len; /**< Amount of data in segment buffer. */
+#ifdef RTE_MBUF_CHAIN_FRIENDLY
+ char pad3[8];
+ void *next;
/* fields on second cache line */
+ char pad4[16] __attribute__((__aligned__(RTE_CACHE_LINE_MIN_SIZE)));
+ void *pool;
+#else
+ /* fields on second cache line */
char pad3[8] __attribute__((__aligned__(RTE_CACHE_LINE_MIN_SIZE)));
void *pool;
void *next;
+#endif
};
/*
diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h
index 15e3a10..6e6ba0e 100644
--- a/lib/librte_mbuf/rte_mbuf.h
+++ b/lib/librte_mbuf/rte_mbuf.h
@@ -765,6 +765,28 @@ typedef uint8_t MARKER8[0]; /**< generic marker with 1B
alignment */
typedef uint64_t MARKER64[0]; /**< marker that allows us to overwrite 8 bytes
* with a single assignment */
+typedef union {
+ uint32_t rss; /**< RSS hash result if RSS enabled */
+ struct {
+ union {
+ struct {
+ uint16_t hash;
+ uint16_t id;
+ };
+ uint32_t lo;
+ /**< Second 4 flexible bytes */
+ };
+ uint32_t hi;
+ /**< First 4 flexible bytes or FD ID, dependent on
+ PKT_RX_FDIR_* flag in ol_flags. */
+ } fdir; /**< Filter identifier if FDIR enabled */
+ struct {
+ uint32_t lo;
+ uint32_t hi;
+ } sched; /**< Hierarchical scheduler */
+ uint32_t usr; /**< User defined tags. See rte_distributor_process()
*/
+} rss_hash_t;
+
/**
* The generic rte_mbuf, containing a packet mbuf.
*/
@@ -824,28 +846,31 @@ struct rte_mbuf {
uint16_t data_len; /**< Amount of data in segment buffer. */
/** VLAN TCI (CPU order), valid if PKT_RX_VLAN_STRIPPED is set. */
uint16_t vlan_tci;
+#ifdef RTE_MBUF_CHAIN_FRIENDLY
+ /*
+ * Move offload into the second cache line and next in the first.
+ * Better performance for applications using chained mbufs to have
+ * the next pointer in the first cache line.
+ * If you change this structure, you must change the user-mode
+ * version in rte_kni_common.h to match the new layout.
+ */
+ uint32_t seqn; /**< Sequence number. See also rte_reorder_insert() */
+ uint16_t vlan_tci_outer; /**< Outer VLAN Tag Control Identifier (CPU
order) */
+ struct rte_mbuf *next; /**< Next segment of scattered packet. */
+
+ /* second cache line - fields only used in slow path or on TX */
+ MARKER cacheline1 __rte_cache_min_aligned;
+
+ rss_hash_t hash; /**< hash information */
union {
- uint32_t rss; /**< RSS hash result if RSS enabled */
- struct {
- union {
- struct {
- uint16_t hash;
- uint16_t id;
- };
- uint32_t lo;
- /**< Second 4 flexible bytes */
- };
- uint32_t hi;
- /**< First 4 flexible bytes or FD ID, dependent on
- PKT_RX_FDIR_* flag in ol_flags. */
- } fdir; /**< Filter identifier if FDIR enabled */
- struct {
- uint32_t lo;
- uint32_t hi;
- } sched; /**< Hierarchical scheduler */
- uint32_t usr; /**< User defined tags. See
rte_distributor_process() */
- } hash; /**< hash information */
+ void *userdata; /**< Can be used for external metadata */
+ uint64_t udata64; /**< Allow 8-byte userdata on 32-bit */
+ };
+
+ struct rte_mempool *pool; /**< Pool from which mbuf was allocated. */
+#else
+ rss_hash_t hash; /**< hash information */
uint32_t seqn; /**< Sequence number. See also rte_reorder_insert() */
@@ -862,7 +887,7 @@ struct rte_mbuf {
struct rte_mempool *pool; /**< Pool from which mbuf was allocated. */
struct rte_mbuf *next; /**< Next segment of scattered packet. */
-
+#endif
/* fields to support TX offloads */
union {
uint64_t tx_offload; /**< combined for easy fetch */
--
2.8.0.GIT
