[Winpcap-users] Delay receiving packets - wrong functionality ofpcap_setmintocopy()

[Gianluca Varenni]

Anton,

You say that you are using a Chelsio board. Are you using the official version of WinPcap or Chelsio provided you with a custom one? What do you set as timeout and mintocopy?

Have a nice day
GV


From: winpcap-users-bounces at winpcap.org [mailto:winpcap-users-bounces at winpcap.org] On Behalf Of Mark Pizzolato - WinPCap-Users
Sent: Friday, January 28, 2011 11:57 AM
To: winpcap-users at winpcap.org
Subject: Re: [Winpcap-users] Delay receiving packets - wrong functionality ofpcap_setmintocopy()

Ho Anton,

My first question to you would be:

WHY are you using WinPcap to receive UDP packets?

This sounds like a job for a winsock application....


-          Mark Pizzolato

From: winpcap-users-bounces at winpcap.org [mailto:winpcap-users-bounces at winpcap.org] On Behalf Of Anton Tremsin
Sent: Friday, January 28, 2011 11:50 AM
To: winpcap-users at winpcap.org
Subject: [Winpcap-users] Delay receiving packets - wrong functionality ofpcap_setmintocopy()

I hope someone can help my problem receiving packets in Windows7

I am sending data by UDP packets from an FPGA through 10GB card (Chelsio). Using VC++ 2010 to compile code to receive them.

All packets arrive, no losses seen, but the problem is with the proper operation of pcap_setmintocopy() function.

I send 64 packets with 8234 bytes each. Receiving them through pcp_next_ex() and I only get 31 packets (sometimes 62, sometimes 47, 50 packets) before the timeout occurs. After timeout the rest of the packets arrives.

I set the minimum amount of data in the kernel buffer that causes a read from the application to return (unless the timeout expires) to be 1 byte or it to be all 8234x64 bytes, no difference. Looks like the setmintocpy function has no effect on my kernel buffer to be copied to my application. If I send another set of 64 packets - data arrives into pcp_next_ex(), still only in lamp of 31 (62, 47,50) packets

That is a big problem for my application.

Is there anything I am doing wrong or need to change something in the system/driver to make setmintocopy function to operate properly?

Thanks a lot for your help,

Anton Tremsin


--



Anton S. Tremsin, Ph.D.

Space Sciences Laboratory

University of California at Berkeley

Berkeley, CA 94720

Tel: (510) 642 4554
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