Hi ,<br><br><br><div class="gmail_quote"><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><div bgcolor="#ffffff"><div><font size="2"></font><div class="im">
>>2. Which function in the NPF or
Packet.dll can be used as a trigger to request CPU timer, like
queryperformancecounter (), to >>timestamp the arrival packet to obatin higher
precision?</div></div>
<div><font size="2"></font> </div>
<div><font size="2">>>--GV--</font></div>
<div><font size="2">>>There is no way to obtain higher precision than we are
currently using in WinPcap, apart from using custom hardware that >>timestamps the
packets in the hardware itself.</font></div><font size="2"></font>
<div><font size="2">>>--GV--</font></div></div></blockquote><div><br><span style="background-color: rgb(255, 255, 255); color: rgb(51, 51, 255);">Is there any possible to know that which function inside WinPcap is used to timestamp the packets?</span><br>
<br><br></div><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><div bgcolor="#ffffff"><div><div class="im"><br>>>4. Can I reduce the size of the user
buffer inside the NPF to set it small enough to triger the CPU timer to
timestamp when >>every packet is arrival?<br></div></div>
<div><font size="2">>>-GV--</font></div>
<div><font size="2">>>Timestamps are generated before the packet is stored in the
buffers. So changing the buffer size doesn't help.</font></div>
<div><font size="2">>>--GV--</font></div><div class="im">
<div><font size="2"></font> </div></div></div></blockquote><div><span style="background-color: rgb(255, 255, 255); color: rgb(51, 51, 255);">Because I try to timestamp the arrival packets again by using my timing functions, I'm looking for a trigger. As I know, the frequency of NPF copying the arrival packets from kernel space to user space depends on the size of user buffer. If I can set the size of user buffer as same as the size of one arrival packet, then, the NPF would copy every single packet from kernel space to user space</span><br style="color: rgb(51, 51, 255);">
<span style="color: rgb(51, 51, 255);">once the packet arrives. And I can use this operation as a trigger to timestamp the arrival packet again with my timing functions, am I right?</span><br style="background-color: rgb(51, 204, 255);">
<br>Cheers<br><br>John<br></div></div>