[Winpcap-users] About the packets loss , what is the bottleneck ?

[Gianluca Varenni]

From: yulou liu 
Sent: Sunday, September 19, 2010 12:50 AM
To: winpcap-users at winpcap.org 
Subject: [Winpcap-users] About the packets loss , what is the bottleneck ?



There is still the question about packets loss.
  
According to the essay  ' Profiling and Optimization of Software-Based Network-Analysis Applications' ,    every packet is copied twice in the main memory before reaching the user.  In order to reduce the cost of CPU and the bus occupying of the SDRAM of pc,   is it possible to copy data directly from the kernel buffer to the final buffer ,  which I want the date kept  in ?   

GV> Not at the moment with WinPcap. Having said that, I've used this double copy mechanism to bring several Gbps's to user mode without any packet loss (not with WinPcap, with custom hardware. However the buffering mechanism was the same).

  
Here is another idea ---  allocate several different user buffers , once a user buffer is fulled , then let the next user buffer to save the new datas from kernel buffer.  Meanwhile copy datas from the first user buffer to disk (assume that the hard disk write rate is fast enough).  Is this idea work with the winpcap ? 

GV>Are you dumping the packets to disk? If so, have you measured the dump-to-disk bandwidth? 

GV


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