On Mon, 5 Jun 2017 22:08:07 +0530, Jerin Jacob <jerin.ja...@caviumnetworks.com> wrote: > There is no need for initializing the complete > packet buffer with zero as the packet data area will be > overwritten by the NIC Rx HW anyway. > > The testpmd configures the packet mempool > with around 180k buffers with > 2176B size. In existing scheme, the init routine > needs to memset around ~370MB vs the proposed scheme > requires only around ~44MB on 128B cache aligned system. > > Useful in running DPDK in HW simulators/emulators, > where millions of cycles have an impact on boot time. > > Signed-off-by: Jerin Jacob <jerin.ja...@caviumnetworks.com> > --- > lib/librte_mbuf/rte_mbuf.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/lib/librte_mbuf/rte_mbuf.c b/lib/librte_mbuf/rte_mbuf.c > index 0e3e36a58..1d5ce7816 100644 > --- a/lib/librte_mbuf/rte_mbuf.c > +++ b/lib/librte_mbuf/rte_mbuf.c > @@ -131,8 +131,7 @@ rte_pktmbuf_init(struct rte_mempool *mp, > RTE_ASSERT(mp->elt_size >= mbuf_size); > RTE_ASSERT(buf_len <= UINT16_MAX); > > - memset(m, 0, mp->elt_size); > - > + memset(m, 0, mbuf_size + RTE_PKTMBUF_HEADROOM); > /* start of buffer is after mbuf structure and priv data */ > m->priv_size = priv_size; > m->buf_addr = (char *)m + mbuf_size;
Yes, I don't foresee any risk to do that. I'm just wondering why RTE_PKTMBUF_HEADROOM should be zeroed. For example, rte_pktmbuf_free() does not touch the data either, so after some packets processing, we also have garbage data in the headroom. Olivier
