About "500 packets in current version"

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This topic contains 5 replies, has 2 voices, and was last updated by  lovepkfilter 10 years, 2 months ago.

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  • #5133

    lovepkfilter
    Participant

    hi!
    can u tell me what’s the meaning for “500 packets”

    in what situation,we need modi the value?

    it Impact the program in some Degree?

    #6447

    Vadim Smirnov
    Moderator

    can u tell me what’s the meaning for “500 packets”

    WinpkFilter driver preallocates 500 buffers for packets (to avoid overhead from allocate/release operations).

    in what situation,we need modi the value?

    User mode WinpkFilter application usually is not the only application running on the system and it is possible that it won’t get processor time (to read packets from driver) during some time interval. During this time interval packets are stored in the driver preallocated buffers. Once application gets processor time it can read packets from the driver and process. If your application can be prevented from execution for large time intervals but still gets enough processor time to read and filter packets on the high speed network then you may need to increase the amount of preallocated packet buffers.

    An example, real network throughput for 100 Mbit network is about 10 megabytes per second. The maximum size of the Ethernet frame is 1514 bytes. The simple calculation gives you approximately 7000 packet per second rate on 100 Mbit network. So if WinpkFilter application is prevented from execution for less than 500/7000 ~ 0.07sec time interval you won’t notice any packet loss.

    #6448

    lovepkfilter
    Participant

    3ks for your exciting answer

    on the other hand,:) if my net traffice reach on 7mbps,can cause lose packet?may be!

    i love pkfilter!you are good author!!

    by the way,when i use pkfilter, i found you alloc 1534 bytes for everypacket,why not 1514?? 😛

    #6449

    lovepkfilter
    Participant

    and~~…

    because u had said:my app work in usermode. i want t deal with every packet, but it is still will be done in usermode not in the ring0.

    please tell me System efficiency can Affected much more?

    #6450

    Vadim Smirnov
    Moderator

    on the other hand,Smile if my net traffice reach on 7mbps,can cause lose packet?

    You loose packets ONLY if your application does not get processor time for some relatively large time interval.

    because u had said:my app work in usermode. i want t deal with every packet, but it is still will be done in usermode not in the ring0.

    please tell me System efficiency can Affected much more?

    Of course Ring0 packet processing is more effective than Ring3 one, however most of the modern systems are powerful enough to afford packet processing in user mode even on high speed links.

    by the way,when i use pkfilter, i found you alloc 1534 bytes for everypacket,why not 1514?

    If you mean INTERMEDIATE_BUFFER structure then in addition to raw Ethernet frame it us used to keep some extra information about the packet (NDIS flags, direction and etc…)

    #6451

    lovepkfilter
    Participant

    hi~
    Thx very Much!

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