On Wednesday 22 November 2017 06:54 PM, Kavanagh, Mark B wrote: > + 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 > Sorry for late reply. I'm reviewing changeset now and Will share my feedback on series: [PATCH v8 01/13] netdev-dpdk: fix mbuf sizing.
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