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From: Bruce Richardson <bruce.richardson@intel.com>
To: Jerin Jacob <jerin.jacob@caviumnetworks.com>
Cc: dev@dpdk.org, pablo.de.lara.guarch@intel.com
Subject: Re: [dpdk-dev] [PATCH] app/testpmd: add packet data prefetch in macswap loop
Date: Tue, 3 May 2016 10:45:16 +0100	[thread overview]
Message-ID: <20160503094516.GC21300@bricha3-MOBL3> (raw)
In-Reply-To: <1462190377-26865-1-git-send-email-jerin.jacob@caviumnetworks.com>

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 <jerin.jacob@caviumnetworks.com>
> ---
>  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
> 

  parent reply	other threads:[~2016-05-03  9:45 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-05-02 11:59 Jerin Jacob
2016-05-02 17:48 ` De Lara Guarch, Pablo
2016-05-03 12:46   ` Jerin Jacob
2016-05-03  9:45 ` Bruce Richardson [this message]
2016-05-03  9:48   ` De Lara Guarch, Pablo
2016-05-03 10:16     ` Bruce Richardson
2016-05-03  9:50   ` Ivan Boule
2016-05-03 10:20     ` Bruce Richardson
2016-05-10 12:26       ` Ananyev, Konstantin
2016-05-03 14:07 ` [dpdk-dev] [PATCH v2] app/testpmd: add packet data pointer prefetch in the forwarding loop Jerin Jacob
2016-05-03 14:33   ` Thomas Monjalon
2016-06-07 11:19   ` De Lara Guarch, Pablo
2016-06-08 15:57     ` Thomas Monjalon

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