The mempool pointer in the mbuf struct is moved
from the second to the first half.
It should increase performance on most systems having 64-byte cache line,
i.e. mbuf is split in two cache lines.
Due to this change, tx_offload is moved, so some vector data paths
may need to be adjusted. Note: OCTEON TX2 check is removed temporarily!
Moving this field gives more space to dynfield1.
This is how the mbuf layout looks like (pahole-style):
word type name byte size
0 void * buf_addr; /* 0 + 8 */
1 rte_iova_t buf_iova /* 8 + 8 */
/* --- RTE_MARKER64 rearm_data; */
2 uint16_t data_off; /* 16 + 2 */
uint16_t refcnt; /* 18 + 2 */
uint16_t nb_segs; /* 20 + 2 */
uint16_t port; /* 22 + 2 */
3 uint64_t ol_flags; /* 24 + 8 */
/* --- RTE_MARKER rx_descriptor_fields1; */
4 uint32_t union packet_type; /* 32 + 4 */
uint32_t pkt_len; /* 36 + 4 */
5 uint16_t data_len; /* 40 + 2 */
uint16_t vlan_tci; /* 42 + 2 */
5.5 uint64_t union hash; /* 44 + 8 */
6.5 uint16_t vlan_tci_outer; /* 52 + 2 */
uint16_t buf_len; /* 54 + 2 */
7 struct rte_mempool * pool; /* 56 + 8 */
/* --- RTE_MARKER cacheline1; */
8 struct rte_mbuf * next; /* 64 + 8 */
9 uint64_t union tx_offload; /* 72 + 8 */
10 struct rte_mbuf_ext_shared_info * shinfo; /* 80 + 8 */
11 uint16_t priv_size; /* 88 + 2 */
uint16_t timesync; /* 90 + 2 */
11.5 uint32_t dynfield1[9]; /* 92 + 36 */
16 /* --- END 128 */
Signed-off-by: Thomas Monjalon <tho...@monjalon.net>
---
doc/guides/rel_notes/deprecation.rst | 7 -------
drivers/net/octeontx2/otx2_ethdev.c | 2 --
lib/librte_kni/rte_kni_common.h | 3 ++-
lib/librte_mbuf/rte_mbuf.h | 1 -
lib/librte_mbuf/rte_mbuf_core.h | 5 ++---
lib/librte_mbuf/rte_mbuf_dyn.c | 1 -
6 files changed, 4 insertions(+), 15 deletions(-)
diff --git a/doc/guides/rel_notes/deprecation.rst
b/doc/guides/rel_notes/deprecation.rst
index f3258eb3f7..efb09f0c5e 100644
--- a/doc/guides/rel_notes/deprecation.rst
+++ b/doc/guides/rel_notes/deprecation.rst
@@ -81,13 +81,6 @@ Deprecation Notices
us extending existing enum/define.
One solution can be using a fixed size array instead of ``.*MAX.*`` value.
-* mbuf: Some fields will be converted to dynamic API in DPDK 20.11
- in order to reserve more space for the dynamic fields, as explained in
- `this presentation <https://www.youtube.com/watch?v=Ttl6MlhmzWY>`_.
- As a consequence, the layout of the ``struct rte_mbuf`` will be re-arranged,
- avoiding impact on vectorized implementation of the driver datapaths,
- while evaluating performance gains of a better use of the first cache line.
-
* ethdev: The flow director API, including ``rte_eth_conf.fdir_conf`` field,
and the related structures (``rte_fdir_*`` and ``rte_eth_fdir_*``),
will be removed in DPDK 20.11.
diff --git a/drivers/net/octeontx2/otx2_ethdev.c
b/drivers/net/octeontx2/otx2_ethdev.c
index 6cebbe677d..d6e0f1dd03 100644
--- a/drivers/net/octeontx2/otx2_ethdev.c
+++ b/drivers/net/octeontx2/otx2_ethdev.c
@@ -748,8 +748,6 @@ nix_tx_offload_flags(struct rte_eth_dev *eth_dev)
offsetof(struct rte_mbuf, buf_iova) + 16);
RTE_BUILD_BUG_ON(offsetof(struct rte_mbuf, pkt_len) !=
offsetof(struct rte_mbuf, ol_flags) + 12);
- RTE_BUILD_BUG_ON(offsetof(struct rte_mbuf, tx_offload) !=
- offsetof(struct rte_mbuf, pool) + 2 * sizeof(void *));
if (conf & DEV_TX_OFFLOAD_VLAN_INSERT ||
conf & DEV_TX_OFFLOAD_QINQ_INSERT)
diff --git a/lib/librte_kni/rte_kni_common.h b/lib/librte_kni/rte_kni_common.h
index 36d66e2ffa..ffb3182731 100644
--- a/lib/librte_kni/rte_kni_common.h
+++ b/lib/librte_kni/rte_kni_common.h
@@ -84,10 +84,11 @@ 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. */
+ char pad3[14];
+ void *pool;
/* fields on second cache line */
__attribute__((__aligned__(RTE_CACHE_LINE_MIN_SIZE)))
- void *pool;
void *next; /**< Physical address of next mbuf in kernel. */
};
diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h
index 3190a29cce..c4c9ebfaa0 100644
--- a/lib/librte_mbuf/rte_mbuf.h
+++ b/lib/librte_mbuf/rte_mbuf.h
@@ -1107,7 +1107,6 @@ rte_pktmbuf_attach_extbuf(struct rte_mbuf *m, void
*buf_addr,
static inline void
rte_mbuf_dynfield_copy(struct rte_mbuf *mdst, const struct rte_mbuf *msrc)
{
- memcpy(&mdst->dynfield0, msrc->dynfield0, sizeof(mdst->dynfield0));
memcpy(&mdst->dynfield1, msrc->dynfield1, sizeof(mdst->dynfield1));
}
diff --git a/lib/librte_mbuf/rte_mbuf_core.h b/lib/librte_mbuf/rte_mbuf_core.h
index debaace95a..567551deab 100644
--- a/lib/librte_mbuf/rte_mbuf_core.h
+++ b/lib/librte_mbuf/rte_mbuf_core.h
@@ -586,12 +586,11 @@ struct rte_mbuf {
uint16_t buf_len; /**< Length of segment buffer. */
- uint64_t dynfield0[1]; /**< Reserved for dynamic fields. */
+ struct rte_mempool *pool; /**< Pool from which mbuf was allocated. */
/* second cache line - fields only used in slow path or on TX */
RTE_MARKER cacheline1 __rte_cache_min_aligned;
- struct rte_mempool *pool; /**< Pool from which mbuf was allocated. */
struct rte_mbuf *next; /**< Next segment of scattered packet. */
/* fields to support TX offloads */
@@ -645,7 +644,7 @@ struct rte_mbuf {
/** Timesync flags for use with IEEE1588. */
uint16_t timesync;
- uint32_t dynfield1[7]; /**< Reserved for dynamic fields. */
+ uint32_t dynfield1[9]; /**< Reserved for dynamic fields. */
} __rte_cache_aligned;
/**
diff --git a/lib/librte_mbuf/rte_mbuf_dyn.c b/lib/librte_mbuf/rte_mbuf_dyn.c
index fd3e019a22..7d5e942bf0 100644
--- a/lib/librte_mbuf/rte_mbuf_dyn.c
+++ b/lib/librte_mbuf/rte_mbuf_dyn.c
@@ -125,7 +125,6 @@ init_shared_mem(void)
* rte_mbuf_dynfield_copy().
*/
memset(shm, 0, sizeof(*shm));
- mark_free(dynfield0);
mark_free(dynfield1);
/* init free_flags */
--
2.28.0
