On 18/06/2018 12:20, Eelco Chaudron wrote:
>
>
> On 11 Jun 2018, at 18:21, Tiago Lam wrote:
>
[snip]
>>
>> @@ -626,13 +622,31 @@ dpdk_mp_create(struct netdev_dpdk *dev, int mtu)
>> netdev_name, n_mbufs, socket_id,
>> dev->requested_n_rxq, dev->requested_n_txq);
>>
>> + mbuf_priv_data_len = sizeof(struct dp_packet) -
>> + sizeof(struct rte_mbuf);
>> + /* The size of the entire mbuf. */
>> + mbuf_size = sizeof (struct dp_packet) +
>> + mbuf_pkt_data_len +
>> RTE_PKTMBUF_HEADROOM;
>> + /* mbuf size, rounded up to cacheline size. */
>> + aligned_mbuf_size = ROUND_UP(mbuf_size, RTE_CACHE_LINE_SIZE);
>> + /* If there is a size discrepancy, add padding to
>> mbuf_priv_data_len.
>> + * This maintains mbuf size cache alignment, while also
>> honoring RX
>> + * buffer alignment in the data portion of the mbuf. If this
>> adjustment
>> + * is not made, there is a possiblity later on that for an
>> element of
>> + * the mempool, buf, buf->data_len < (buf->buf_len -
>> buf->data_off).
>> + * This is problematic in the case of multi-segment mbufs,
>> particularly
>> + * when an mbuf segment needs to be resized (when
>> [push|popp]ing a VLAN
>> + * header, for example.
>> + */
>> + mbuf_priv_data_len += (aligned_mbuf_size - mbuf_size);
>> +
>> 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);
>> + mbuf_priv_data_len,
>> + mbuf_pkt_data_len + RTE_PKTMBUF_HEADROOM, socket_id);
>>
>> if (mp) {
>> VLOG_DBG("Allocated \"%s\" mempool with %u mbufs",
>> - mp_name, n_mbufs);
>> + mp_name, n_mbufs);
>
> While you are at it, can we add some info on the cache line alignment
> size, might be useful for debugging.
Sure. I'll add it to the next iteration.
Tiago.
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