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<TITLE>RE: [openib-general] [PATCH] Add support for querying port width/speed</TITLE>
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<P><FONT SIZE=2>I think the choice of IPD is beyond the scope of the IB spec. The spec provides a mechanism to regulate the injection rate but does not mandate its use. Your assumption below (rounding up) makes perfect sense. Rounding down would defeat the entire purpose of the IPD mechanism.</FONT></P>
<P><FONT SIZE=2>Diego</FONT>
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<P><FONT SIZE=2>> -----Original Message-----</FONT>
<BR><FONT SIZE=2>> From: Roland Dreier [<A HREF="mailto:roland@topspin.com">mailto:roland@topspin.com</A>] </FONT>
<BR><FONT SIZE=2>> Sent: Tuesday, December 28, 2004 3:11 AM</FONT>
<BR><FONT SIZE=2>> To: openib-general@openib.org</FONT>
<BR><FONT SIZE=2>> Subject: Re: [openib-general] [PATCH] Add support for </FONT>
<BR><FONT SIZE=2>> querying port width/speed</FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> By, the way does anyone know what IPD is supposed to be used </FONT>
<BR><FONT SIZE=2>> when the injection port's rate is not a multiple of the rate </FONT>
<BR><FONT SIZE=2>> for the path? For example, suppose an 8X DDR port is sending </FONT>
<BR><FONT SIZE=2>> to a 12X path -- 12 doesn't divide 16 evenly.</FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> I would guess that the correct thing to do is round up, so 8X DDR</FONT>
<BR><FONT SIZE=2>> -> 12X uses an IPD of 1, 8X QDR -> 12X uses an IPD of 2, etc.</FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> - R.</FONT>
<BR><FONT SIZE=2>> </FONT>
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