<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=us-ascii">
<TITLE>Message</TITLE>
<META content="MSHTML 6.00.2800.1458" name=GENERATOR></HEAD>
<BODY>
<DIV><SPAN class=069135319-26092004><FONT face=Arial color=#0000ff
size=2>completing the list...</FONT></SPAN></DIV>
<BLOCKQUOTE dir=ltr
style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #0000ff 2px solid; MARGIN-RIGHT: 0px">
<DIV></DIV>
<DIV class=OutlookMessageHeader lang=en-us dir=ltr align=left><FONT
face=Tahoma size=2>-----Original Message-----<BR><B>From:</B> Dror Goldenberg
[mailto:gdror@mellanox.co.il] <BR><B>Sent:</B> Sunday, September 26, 2004 8:17
PM<BR><B>To:</B> Sean Hefty; Fab Tillier<BR><B>Cc:</B>
openib-general@openib.org<BR><B>Subject:</B> RE: [openib-general] ib_mad
shutdown WC status code ?<BR><BR></FONT></DIV><BR><BR>
<P><FONT size=2>> -----Original Message-----</FONT> <BR><FONT size=2>>
From: Sean Hefty [<A
href="mailto:mshefty@ichips.intel.com">mailto:mshefty@ichips.intel.com</A>]
</FONT><BR><FONT size=2>> Sent: Friday, September 24, 2004 6:41 PM</FONT>
</P>
<P><FONT size=2>> I think that flushed makes sense. With queuing in
the access </FONT><BR><FONT size=2>> layer, we should be able to stop and
restart the QP in most </FONT><BR><FONT size=2>> error cases without
affecting the user. If the link goes </FONT><BR><FONT size=2>> down,
flushing the requests seems reasonable. What other </FONT><BR><FONT
size=2>> cases would cause the MAD layer to shut down?</FONT> <BR><FONT
size=2>> </FONT></P>
<P><FONT size=2>If link goes down, UD QP will go on "sending" the packets
as</FONT> <BR><FONT size=2>if link was up all the time. You wouldn't get
flushed WQEs in this</FONT> <BR><FONT size=2>case for a UD
QP.</FONT> <SPAN class=069135319-26092004><FONT face=Arial color=#0000ff
size=2> Receive queue is unaffected by the link<BR>going
down.</FONT></SPAN><SPAN class=069135319-26092004> </SPAN><BR><FONT
size=2>In general, for UD QPs, you'll get flushed WQEs when the QP</FONT>
<BR><FONT size=2>moves to the error state and that seldom happens. The
exact</FONT> <BR><FONT size=2>scenarios for this to happen (hopefully I don't
miss anything):</FONT> <BR><FONT size=2>- s/g element points at a wrong
address/protection error</FONT> <BR><FONT size=2>- HCA can't fetch a WQE (e.g.
bus error)</FONT> <SPAN class=069135319-26092004><FONT face=Arial
color=#0000ff size=2> <BR>- manually move the QP to the error state
(modify QP)</FONT></SPAN><SPAN class=069135319-26092004> </SPAN></P>
<P><FONT size=2>-Dror</FONT> </P>
<P><FONT size=2>> - Sean</FONT> </P></BLOCKQUOTE></BODY></HTML>