[Winpcap-users] is winpcap appropriate for mygigabitethernetdevice?

max reason maxreason at maxreason.com
Fri Sep 5 08:25:10 GMT 2008

 I was almost certain one SATAII disk wouldn't keep up, and almost
 certain two disks would work with just enough margin to be reliable.
 However, you are the second person to mention RAID - I don't understand.
 As long as the computer has two disk controllers (which many do),
 I assumed my application could alternately write to the two drives
 and expect everything to work.  Or is there something special about
 one or more of the RAID modes that I don't know about?

 Is your suggestion to "disable file system caching" while dumping
 to disk related to the CPU cache concerns I expressed in my reply
 to Zafer Savas?  Or do you refer to the memory cache on the disk?

 In those applications where the speed of the computer system and
 peripherals are pushed to the limit, my $250 ~ $500 device replaces
 $12,000 ~ $38,000 alternatives!  Therefore, it is entirely reasonable
 to *require* the computer is doing nothing else (of significance)
 during high-speed image capture/display/save.  This also means it
 is perfectly okay to put the computer into special configurations
 while the capture process is active.  So, it is perfectly okay to
 lock any quantity of memory that doesn't interfere with the OS or
 peripheral controllers doing their jobs.  Therefore, the kind of
 tips you give are relevant and very appreciated.

 Thanks much.  And yes, your and Zafer have made my day nice indeed!
 Well, and winpcap of course!  :-)


> To add something to it.  If your main objective is dumping to disk,
> by far the most important things are:
>   1. use RAID. A single disk CANNOT keep up.
>   2. you can also use one single thread and use overlapped i/o to
>      dump to disk.  And disable file system caching while dumping
>      to disk (you do that with the flags of CreateFile).
> Creating big buffers in user mode is not always useful. Unless you
> lock all that amount of memory so that it's in your working set
> (i.e. it's not swapped out), the risk is that that big amount of
> memory gets swapped in/out to disk when you use it (because the OS
> tries to trim your working set size).
> I played a lot with these things recently while developing TurboCap,
> and these were the major bottlenecks when dumping to disk.
> Have a nice day
> GV

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