From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bruce Richardson Subject: Re: [PATCH] app/testpmd: add packet data prefetch in macswap loop Date: Tue, 3 May 2016 10:45:16 +0100 Message-ID: <20160503094516.GC21300@bricha3-MOBL3> References: <1462190377-26865-1-git-send-email-jerin.jacob@caviumnetworks.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: dev@dpdk.org, pablo.de.lara.guarch@intel.com To: Jerin Jacob Return-path: Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by dpdk.org (Postfix) with ESMTP id 060FD5908 for ; Tue, 3 May 2016 11:45:37 +0200 (CEST) Content-Disposition: inline In-Reply-To: <1462190377-26865-1-git-send-email-jerin.jacob@caviumnetworks.com> List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" On Mon, May 02, 2016 at 05:29:37PM +0530, Jerin Jacob wrote: > prefetch the next packet data address in advance in macswap loop > for performance improvement. > > Signed-off-by: Jerin Jacob > --- > app/test-pmd/macswap.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/app/test-pmd/macswap.c b/app/test-pmd/macswap.c > index 154889d..c10f4b5 100644 > --- a/app/test-pmd/macswap.c > +++ b/app/test-pmd/macswap.c > @@ -113,6 +113,9 @@ pkt_burst_mac_swap(struct fwd_stream *fs) > if (txp->tx_ol_flags & TESTPMD_TX_OFFLOAD_INSERT_QINQ) > ol_flags |= PKT_TX_QINQ_PKT; > for (i = 0; i < nb_rx; i++) { > + if (likely(i < nb_rx - 1)) > + rte_prefetch0(rte_pktmbuf_mtod(pkts_burst[i + 1], > + void *)); At least on IA platforms, there is no issue with prefetching beyond the end of the array, since it's only a hint to the cpu. If this is true for other platforms, then I suggest we just drop the conditional and just always prefetch. /Bruce > mb = pkts_burst[i]; > eth_hdr = rte_pktmbuf_mtod(mb, struct ether_hdr *); > > -- > 2.1.0 >