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From: Stephen Hemminger <stephen@networkplumber.org>
To: Shailja Pandey <csz168117@iitd.ac.in>
Cc: dev@dpdk.org
Subject: Re: [dpdk-dev] How to update the sequence number in TCP packets using DPDK-pktgen?
Date: Tue, 10 Oct 2017 16:00:00 -0700	[thread overview]
Message-ID: <20171010160000.348d2930@shemminger-XPS-13-9360> (raw)
In-Reply-To: <c8dde074-7192-e7dd-b8b8-857f370e4649@iitd.ac.in>

On Mon, 9 Oct 2017 19:12:49 +0530
Shailja Pandey <csz168117@iitd.ac.in> wrote:

> pktgen_tcp_hdr_ctor(pkt_seq_t *pkt, tcpip_t *tip, int type __rte_unused)
> {
>          uint16_t tlen;
> 
>          /* Zero out the header space */
>          memset((char *)tip, 0, sizeof(tcpip_t));
> 
>          /* Create the TCP header */
>          tip->ip.src         = htonl(pkt->

FYI memset is a performance hit. Gcc generates a rep string instruction
which slows down CPU.. Better to do either set all fields individually
or fill in the pad values by doing structure assignment.

	*tip = (tcpi_ip_t) {
		.ip.src = htonl(pkt->ip_src_addr.addr.ipv4_saddr),
	...
	};

  parent reply	other threads:[~2017-10-10 23:00 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-10-09 13:42 Shailja Pandey
2017-10-09 17:12 ` Wiles, Keith
2017-10-10 23:00 ` Stephen Hemminger [this message]
2017-10-11  0:10   ` Wiles, Keith

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