Hi Bruce, > -----Original Message----- > From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Bruce Richardson > Sent: Thursday, September 11, 2014 9:16 PM > To: dev at dpdk.org > Subject: [dpdk-dev] [PATCH v2 02/13] mbuf: reorder fields by time of use > > * 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, and a > block of 16-bytes of data (excluding flags) which are set on RX from the > received packet descriptor. > * Use dummy fields as appropriate to ensure alignment or to reserve gaps for > later field additions. > * Place most items which are not used by fast-path RX separately at the end of > the structure so they can later be moved to a separate cache line. > [The l2/l3 length fields are not moved at this stage as doing so will cause > overflow to the next cache line]. > > Updated in V2: > * Updated the KNI buffer structure to match that of new mbuf > * Cleaned up commit message typos. > > Signed-off-by: Bruce Richardson <bruce.richardson at intel.com> > --- > .../linuxapp/eal/include/exec-env/rte_kni_common.h | 12 ++++++----- > lib/librte_mbuf/rte_mbuf.h | 25 > ++++++++++++---------- > 2 files changed, 21 insertions(+), 16 deletions(-) > > 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 07908ac..f2b502c 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 > @@ -108,15 +108,17 @@ struct rte_kni_fifo { > * Padding is necessary to assure the offsets of these fields > */ > struct rte_kni_mbuf { > - void *pool; > void *buf_addr; > - char pad0[16]; > - void *next; > + char pad0[10]; > uint16_t data_off; /**< Start address of data in segment buffer. */ > + char pad1[4]; > + uint16_t ol_flags; /**< Offload features. */ > + char pad2[8]; > uint16_t data_len; /**< Amount of data in segment buffer. */ > uint32_t pkt_len; /**< Total pkt len: sum of all segment data_len. > */ > - char pad2[4]; > - uint16_t ol_flags; /**< Offload features. */ > + char pad3[8]; > + void *pool; > + void *next; > } __attribute__((__aligned__(64))); > > /* > diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h index > 71080e5..413a5a1 100644 > --- a/lib/librte_mbuf/rte_mbuf.h > +++ b/lib/librte_mbuf/rte_mbuf.h > @@ -115,16 +115,12 @@ extern "C" { > * 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 */ > + 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 > /** > @@ -142,14 +138,17 @@ struct rte_mbuf { > #else > uint16_t refcnt_reserved; /**< Do not use this field */ > #endif > - uint16_t reserved; /**< Unused field. Required for padding > */ > - uint16_t ol_flags; /**< Offload features. */ > - > - /* these fields are valid for first segment only */ > uint8_t nb_segs; /**< Number of segments. */ > uint8_t port; /**< Input port. */ > > - /* offload features, valid for first segment only */ > + uint16_t ol_flags; /**< Offload features. */ > + uint16_t reserved0; /**< Unused field. Required for padding */ > + uint32_t reserved1; /**< Unused field. Required for padding */ > + > + /* remaining bytes are set on RX when pulling packet from descriptor */ > + uint16_t reserved2; /**< Unused field. Required for padding */ > + uint16_t data_len; /**< Amount of data in segment buffer. */ > + uint32_t pkt_len; /**< Total pkt len: sum of all segments. */ > union { > uint16_t l2_l3_len; /**< combined l2/l3 lengths as single var */ > struct { > @@ -167,6 +166,10 @@ struct rte_mbuf { > uint32_t sched; /**< Hierarchical scheduler */ > } hash; /**< hash information */ > > + /* 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
It seems that you removed the inner_l3_len and inner_l2_len fields from the rte_mbuf.h structure, what is the reason? /Jijiang Liu
