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<TITLE>the max_send/recv_sge value in the QP creation init attribute can't accept max s/g value in memfree devices for UD QPs</TITLE>
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<P><FONT SIZE=2 FACE="Arial">in memfree Mellanox HCAs (for example: 25204) there is a problem with the s/g size in the mthca driver</FONT>
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<P><FONT SIZE=2 FACE="Arial">the reported value (from the query HCA verb in user level) is 30.</FONT>
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<P><FONT SIZE=2 FACE="Arial">when i try to create an RC QP with 30 s/g entries it fails (with 29 s/g the QP can be created)</FONT>
<BR><FONT SIZE=2 FACE="Arial">when i try to create an UD QP with 28 s/g entries it fails (with 27 s/g the QP can be created)</FONT>
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<P><FONT SIZE=2 FACE="Arial">there are 2 issues:</FONT>
<BR><FONT SIZE=2 FACE="Arial">1) the query HCA report a higher value of s/g entries than the HCA can support</FONT>
<BR><FONT SIZE=2 FACE="Arial">2) which value should be reported by the query HCA as the maximum supported value of s/g entries in a QP?</FONT>
<BR> <FONT SIZE=2 FACE="Arial">29: which is supported only by RC/UC QPs</FONT>
<BR> <FONT SIZE=2 FACE="Arial">or</FONT>
<BR> <FONT SIZE=2 FACE="Arial">28: which is supported by all transport types (but decrease the number of s/g entries that an RC QP can support)</FONT></P>
<P><FONT SIZE=2 FACE="Arial">what do you think?</FONT>
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<P><B><I><FONT COLOR="#008080" SIZE=6 FACE="Script">Dotan Barak</FONT></I></B>
<BR><FONT FACE="Times New Roman">Software Verification Engineer</FONT>
<BR><FONT FACE="Times New Roman">Mellanox Technologies LTD</FONT>
<BR><FONT FACE="Times New Roman">Tel: +972-4-9097200 Ext: 231 Fax: +972-4-9593245</FONT>
<BR><FONT FACE="Times New Roman">P.O. Box 86 Yokneam 20692 ISRAEL.</FONT>
<BR><FONT FACE="Times New Roman">Home: +972-77-8841095 Cell: 0</FONT><FONT SIZE=2 FACE="Arial">52-4222383</FONT>
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<P><FONT COLOR="#008080" SIZE=2 FACE="Arial">[ May the fork be with you ]</FONT>
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