[dpdk-dev] [PATCH] pktgen-dpdk: fix low performance in VM virtio pmd mode

Wiles, Keith keith.wiles at intel.com
Wed Dec 20 15:04:50 CET 2017



> On Dec 20, 2017, at 2:04 AM, Bin Huang <huangbin.mails at gmail.com> wrote:
> 
> pktgen pre-allocated TX data in mbuf would be modified by virtio pmd driver due to virtio pkt head extension.
> it will caused mbuf data_len keep growing, packets size on wire growing, then tx pps performance drop.
> 
> set corresponding mbuf data_len in pktmbuf reset to fix it.
> 
> Signed-off-by: Bin Huang <huangbin.mails at gmail.com>
> Signed-off-by: Bin Huang <bin.huang at hxt-semitech.com>
> Signed-off-by: Bin Huang <huangbin.mails at gmail.com>
> ---
> lib/common/mbuf.h | 1 +
> 1 file changed, 1 insertion(+)
> 
> diff --git a/lib/common/mbuf.h b/lib/common/mbuf.h
> index 759f95d..93065f6 100644
> --- a/lib/common/mbuf.h
> +++ b/lib/common/mbuf.h
> @@ -18,6 +18,7 @@ pktmbuf_reset(struct rte_mbuf *m)
> 	m->nb_segs = 1;
> 	m->port = 0xff;
> 
> +	m->data_len = m->pkt_len;
> 	m->data_off = (RTE_PKTMBUF_HEADROOM <= m->buf_len) ?
> 		RTE_PKTMBUF_HEADROOM : m->buf_len;
> }
> -- 
> 2.7.4

Thank you for the patch, this maybe the problem a few others have seen.
> 

Regards,
Keith



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