Reduce number of GetAdaptersAddresses() calls - #20
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The GetAdaptersAddresses() calls in Packet.dll take over 70% time needed for the Wireshark's "dumpcap -D -Z none". This change addresses the issue by essentially halving the amount of calls to GetAdaptersAddresses() by calling it first with a preallocated 15000 bytes long buffer. According to GetAdaptersAddresses() documentation "On typical computers, this dramatically reduces the chances that the GetAdaptersAddresses function returns ERROR_BUFFER_OVERFLOW, which would require calling GetAdaptersAddresses function multiple times". This change reduces the time "dumpcap -D -Z none" takes by approximately 7.5 seconds. I did 100 time measurements in a row and the results are: * with this change: 10.72 seconds average, 2.99 standard deviation * without this change: 18.18 seconds average, 4.25 standard deviation
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Thanks for this! I'll merge it and add some additional changes: using ReAlloc instead of free+alloc, reducing number of calls to PacketAddIP6Addresses, etc. Should be great! |
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The GetAdaptersAddresses() calls in Packet.dll take over 70% time needed
for the Wireshark's "dumpcap -D -Z none".
This change addresses the issue by essentially halving the amount of
calls to GetAdaptersAddresses() by calling it first with a preallocated
15000 bytes long buffer. According to GetAdaptersAddresses()
documentation "On typical computers, this dramatically reduces the
chances that the GetAdaptersAddresses function returns
ERROR_BUFFER_OVERFLOW, which would require calling GetAdaptersAddresses
function multiple times".
This change reduces the time "dumpcap -D -Z none" takes by approximately
7.5 seconds. I did 100 time measurements in a row and the results are: