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Date: Mon, 19 Mar 2007 16:16:11 -0700 (PDT) From: David Miller <davem@...emloft.net> To: zacco@...hu Cc: baruch@...en.org, netdev@...r.kernel.org Subject: Re: many sockets, slow sendto From: Zacco <zacco@...hu> Date: Tue, 20 Mar 2007 00:10:19 +0100 > As you recommended, I used oprofile and it turned out that the > __udp4_lib_lookup function spent most of the time. There is a udp hash > table and the sockets are sought based on the 7 LSBs of the destination > port number. So what happened is now quite obvious: I had many thousands > of sockets, all with the same destination port, thus linked in the same > slot of this hash table. I tried using different ports and it > was much faster then. There isn't much we can do here. I bet your destination address is unchanging just like your destination ports. UDP apps can and do bind to specific destination addresses and ports, but the source side is usually wild-carded. Are both the source address and port fully specified for your sockets? Maybe we can do something using if that's the case... - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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