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<DIV><FONT face=Tahoma size=2><B>From:</B> Hal Rosenstock
[mailto:hal.rosenstock@gmail.com] <BR><B>Sent:</B> Tuesday, July 24, 2007 5:53
PM<BR><B>To:</B> Eitan Zahavi<BR><B>Cc:</B> OpenFabrics General; Sasha
Khapyorsky; Yevgeny Kliteynik<BR><B>Subject:</B> Re: OpenSM detection of
duplicated GUIDs on loopback<BR></FONT><BR></DIV>
<BLOCKQUOTE
style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #0000ff 2px solid; MARGIN-RIGHT: 0px">
<DIV></DIV>Hi Eitan,<BR><BR>
<DIV><SPAN class=gmail_quote>On 7/24/07, <B class=gmail_sendername>Eitan
Zahavi</B> <<A
href="mailto:eitan@mellanox.co.il">eitan@mellanox.co.il</A>> wrote:</SPAN>
<BLOCKQUOTE class=gmail_quote
style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid">
<DIV>
<DIV><SPAN><FONT face="Palatino Linotype" color=#0000ff><STRONG>Hi
Hal,</STRONG></FONT></SPAN></DIV>
<DIV><SPAN><STRONG><FONT face="Palatino Linotype"
color=#0000ff></FONT></STRONG></SPAN> </DIV>
<DIV><SPAN><STRONG><FONT face="Palatino Linotype" color=#0000ff>What is this
"loopback" connector used for?</FONT></STRONG></SPAN></DIV>
<DIV><SPAN><STRONG><FONT face="Palatino Linotype" color=#0000ff>Does not
seem to me like a very useful thing to
do.</FONT></STRONG></SPAN></DIV></DIV></BLOCKQUOTE>
<DIV><STRONG><FONT face="Palatino Linotype"
color=#0000ff></FONT></STRONG> </DIV>
<DIV>Perhaps not but no reason OpenSM can't handle this more
gracefully.</DIV><BR>
<BLOCKQUOTE class=gmail_quote
style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid">
<DIV>
<DIV><SPAN><STRONG><FONT face="Palatino Linotype" color=#0000ff>Anyway, if
it is not a production environment we could add a "debug mode" (-d flag
option) to ignore this check.</FONT></STRONG></SPAN></DIV></DIV></BLOCKQUOTE>
<DIV><STRONG><FONT face="Palatino Linotype"
color=#0000ff></FONT></STRONG> </DIV>
<DIV>Why would a separate flag be needed ?<BR><SPAN
class=289305114-24072007><STRONG><FONT face="Palatino Linotype"
color=#0000ff>[EZ] Since I do not see any other solution for the SM
to know it is really a loop back plug rather then two devices with same
GUID connected back to back ...</FONT></STRONG></SPAN></DIV>
<DIV><STRONG><FONT face="Palatino Linotype"
color=#0000ff></FONT></STRONG> </DIV>
<DIV>-- Hal</DIV><BR>
<BLOCKQUOTE class=gmail_quote
style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid">
<DIV>
<DIV><STRONG><FONT face="Palatino Linotype"
color=#0000ff></FONT></STRONG> </DIV>
<P><SPAN lang=en-gb><B><I><FONT face="Monotype Corsiva" color=#0000ff
size=6>Eitan Zahavi</FONT></I></B><I></I></SPAN> <BR><SPAN lang=en-gb><FONT
face=Tahoma size=2>Senior Engineering Director, Software Architect
</FONT></SPAN><BR><SPAN lang=en-gb><FONT face=Tahoma size=2>Mellanox
Technologies LTD</FONT></SPAN> <BR><SPAN lang=en-gb><FONT face=Tahoma
size=2>Tel:+972-4-9097208<BR>Fax:+972-4-9593245</FONT></SPAN> <BR><SPAN
lang=en-gb><FONT face=Tahoma size=2>P.O. Box 586 Yokneam 20692
ISRAEL</FONT></SPAN> </P>
<DIV> </DIV><BR>
<BLOCKQUOTE dir=ltr
style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #0000ff 2px solid; MARGIN-RIGHT: 0px">
<DIV lang=en-us dir=ltr align=left>
<HR>
<FONT face=Tahoma size=2><B>From:</B> Hal Rosenstock [mailto:<A
onclick="return top.js.OpenExtLink(window,event,this)"
href="mailto:hal.rosenstock@gmail.com"
target=_blank>hal.rosenstock@gmail.com</A>] <BR><B>Sent: </B>Tuesday, July
24, 2007 5:31 PM<BR><B>To:</B> OpenFabrics General<BR><B>Cc:</B> Sasha
Khapyorsky; Eitan Zahavi; Yevgeny Kliteynik<SPAN
class=q><BR><B>Subject:</B> OpenSM detection of duplicated GUIDs on
loopback<BR></SPAN></FONT><BR> </DIV>
<DIV><SPAN class=e id=q_113f8b21157a3f4b_3>
<DIV></DIV>
<DIV>Hi,</DIV>
<DIV> </DIV>
<DIV>This is what starts off as a "minor" issue and I know it has been
discussed it somewhat in the past: </DIV>
<DIV> </DIV>
<DIV>Putting a loopback connector on a (switch) link causes OpenSM to
indicate duplicated GUID error 0D18 as
follows:<BR><BR>__osm_ni_rcv_set_links<BR>{<BR>...<BR>
/*<BR>
When there are only two nodes with exact same guids (connected back
<BR>
to back) - the previous check for duplicated guid will not
catch<BR>
them. But the link will be from the port to
itself...<BR>
Enhanced Port 0 is an exception to
this<BR> */
<BR> if
((osm_node_get_node_guid( p_node ) == p_ni_context->node_guid)
&&<BR>
(port_num == p_ni_context->port_num)
&&<BR>
(port_num != 0))<BR>
{<BR>
osm_log( p_rcv->p_log, OSM_LOG_ERROR,
<BR>
"__osm_ni_rcv_set_links: ERR 0D18:
"<BR>
"Duplicate GUID found by link from a port to
itself:"<BR>
"node 0x%" PRIx64 ", port number 0x%X\n",
<BR>
cl_ntoh64( osm_node_get_node_guid( p_node )
),<BR>
port_num );<BR>...<BR><BR>So this occurs over and over and over and fills
the log with the same spew. This should be improved IMO. <BR><BR>Is this
really a fatal condition ? Doesn't seem like it should be to me. </DIV>
<DIV> </DIV>
<DIV>Also, OpenSM can "ride" this out with -y (stay on fatal) but is that
safe for this condition ?</DIV>
<DIV> </DIV>
<DIV>Seems like something like an extra loopback bit should be added
to some port structure which should cause these links to be ignored. This
bit would then be reset when the peer is now longer itself. <BR><BR>Also,
is there a relationship of this with the 12x/duplicated GUID code ? </DIV>
<DIV> </DIV>
<DIV>Thanks.</DIV>
<DIV> </DIV>
<DIV>--
Hal<SPAN></SPAN></DIV></SPAN></DIV></BLOCKQUOTE></DIV></BLOCKQUOTE></DIV><BR></BLOCKQUOTE></BODY></HTML>