+ Santosh >From: ovs-dev-boun...@openvswitch.org [mailto:ovs-dev-boun...@openvswitch.org] >On Behalf Of Mark Kavanagh >Sent: Tuesday, November 21, 2017 6:29 PM >To: d...@openvswitch.org; qiud...@chinac.com >Subject: [ovs-dev] [RFC PATCH v3 1/8] netdev-dpdk: simplify mbuf sizing > >When calculating the mbuf data_room_size (i.e. the size of actual >packet data that an mbuf can accomodate), it is possible to simply >use the value calculated by dpdk_buf_size() as a parameter to >rte_pktmbuf_pool_create(). This simplifies mbuf sizing considerably. >This patch removes the related size conversions and macros, which >are no longer needed. > >The benefits of this approach are threefold: >- the mbuf sizing code is much simpler, and more readable. >- mbuf size will always be cache-aligned [1], satisfying that > requirement of specific PMDs (vNIC thunderx, for example). >- the maximum amount of data that each mbuf contains may now be > calculated as mbuf->buf_len - mbuf->data_off. This is important > in the case of multi-segment jumbo frames. > >[1] (this is true since mbuf size is now always a multiple > of 1024, + 128B RTE_PKTMBUF_HEADROOM + 704B dp_packet).
Santosh, I've just spotted that the cacheline size for thunderx is defined as 128B, as opposed to 64. ==> config/defconfig_arm64-thunderx-linuxapp-gcc:36:CONFIG_RTE_CACHE_LINE_SIZE=128 Apologies for the oversight - I'd be very interested to hear your thoughts on this patch. Thanks in advance, Mark > >Fixes: 4be4d22 ("netdev-dpdk: clean up mbuf initialization") >Fixes: 31b88c9 ("netdev-dpdk: round up mbuf_size to cache_line_size") >Signed-off-by: Mark Kavanagh <mark.b.kavan...@intel.com> >--- > lib/netdev-dpdk.c | 22 ++++++++-------------- > 1 file changed, 8 insertions(+), 14 deletions(-) > >diff --git a/lib/netdev-dpdk.c b/lib/netdev-dpdk.c >index 8906423..c5eb851 100644 >--- a/lib/netdev-dpdk.c >+++ b/lib/netdev-dpdk.c >@@ -81,12 +81,6 @@ static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, >20); > + (2 * VLAN_HEADER_LEN)) > #define MTU_TO_FRAME_LEN(mtu) ((mtu) + ETHER_HDR_LEN + ETHER_CRC_LEN) > #define MTU_TO_MAX_FRAME_LEN(mtu) ((mtu) + ETHER_HDR_MAX_LEN) >-#define FRAME_LEN_TO_MTU(frame_len) ((frame_len) \ >- - ETHER_HDR_LEN - ETHER_CRC_LEN) >-#define MBUF_SIZE(mtu) ROUND_UP((MTU_TO_MAX_FRAME_LEN(mtu) \ >- + sizeof(struct dp_packet) \ >- + RTE_PKTMBUF_HEADROOM), \ >- RTE_CACHE_LINE_SIZE) > #define NETDEV_DPDK_MBUF_ALIGN 1024 > #define NETDEV_DPDK_MAX_PKT_LEN 9728 > >@@ -447,7 +441,7 @@ is_dpdk_class(const struct netdev_class *class) > * behaviour, which reduces performance. To prevent this, use a buffer size > * that is closest to 'mtu', but which satisfies the aforementioned criteria. > */ >-static uint32_t >+static uint16_t > dpdk_buf_size(int mtu) > { > return ROUND_UP((MTU_TO_MAX_FRAME_LEN(mtu) + RTE_PKTMBUF_HEADROOM), >@@ -486,7 +480,7 @@ ovs_rte_pktmbuf_init(struct rte_mempool *mp OVS_UNUSED, > * - a new mempool was just created; > * - a matching mempool already exists. */ > static struct rte_mempool * >-dpdk_mp_create(struct netdev_dpdk *dev, int mtu) >+dpdk_mp_create(struct netdev_dpdk *dev, uint16_t frame_len) > { > char mp_name[RTE_MEMPOOL_NAMESIZE]; > const char *netdev_name = netdev_get_name(&dev->up); >@@ -513,12 +507,12 @@ dpdk_mp_create(struct netdev_dpdk *dev, int mtu) > * longer than RTE_MEMPOOL_NAMESIZE. */ > int ret = snprintf(mp_name, RTE_MEMPOOL_NAMESIZE, > "ovs%08x%02d%05d%07u", >- hash, socket_id, mtu, n_mbufs); >+ hash, socket_id, frame_len, n_mbufs); > if (ret < 0 || ret >= RTE_MEMPOOL_NAMESIZE) { > VLOG_DBG("snprintf returned %d. " > "Failed to generate a mempool name for \"%s\". " >- "Hash:0x%x, socket_id: %d, mtu:%d, mbufs:%u.", >- ret, netdev_name, hash, socket_id, mtu, n_mbufs); >+ "Hash:0x%x, socket_id: %d, frame length:%d, mbufs:%u.", >+ ret, netdev_name, hash, socket_id, frame_len, n_mbufs); > break; > } > >@@ -529,7 +523,7 @@ dpdk_mp_create(struct netdev_dpdk *dev, int mtu) > > mp = rte_pktmbuf_pool_create(mp_name, n_mbufs, MP_CACHE_SZ, > sizeof (struct dp_packet) - sizeof (struct rte_mbuf), >- MBUF_SIZE(mtu) - sizeof(struct dp_packet), socket_id); >+ frame_len + RTE_PKTMBUF_HEADROOM, socket_id); > > if (mp) { > VLOG_DBG("Allocated \"%s\" mempool with %u mbufs", >@@ -582,11 +576,11 @@ static int > netdev_dpdk_mempool_configure(struct netdev_dpdk *dev) > OVS_REQUIRES(dev->mutex) > { >- uint32_t buf_size = dpdk_buf_size(dev->requested_mtu); >+ uint16_t buf_size = dpdk_buf_size(dev->requested_mtu); > struct rte_mempool *mp; > int ret = 0; > >- mp = dpdk_mp_create(dev, FRAME_LEN_TO_MTU(buf_size)); >+ mp = dpdk_mp_create(dev, buf_size); > if (!mp) { > VLOG_ERR("Failed to create memory pool for netdev " > "%s, with MTU %d on socket %d: %s\n", >-- >1.9.3 > >_______________________________________________ >dev mailing list >d...@openvswitch.org >https://mail.openvswitch.org/mailman/listinfo/ovs-dev _______________________________________________ dev mailing list d...@openvswitch.org https://mail.openvswitch.org/mailman/listinfo/ovs-dev