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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">This kind of behavior (polling on last byte) is common practice among s/w developers, but you should be forewarned that the specifications DO NOT guarantee
ordered placement of bytes into memory. Based on most existing h/w implementations today it tends to work out, but you should NOT rely on one particular byte to indicate that all preceding bytes have been written correctly.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">A much better approach is to use RDMA Write w/ IMMED, which consumes a receive resource and creates a completion.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">-Paul<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> users-bounces@lists.openfabrics.org [mailto:users-bounces@lists.openfabrics.org]
<b>On Behalf Of </b>jagadeesh kumar<br>
<b>Sent:</b> Friday, December 06, 2013 4:05 AM<br>
<b>To:</b> users@lists.openfabrics.org<br>
<b>Subject:</b> [Users] RDMA WRITE operation using kernel verbs.<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt">Hi all,<br>
<br>
I am learning RDMA_WRITE operation using OFED Verbs(Kernel space).<br>
As RDMA_WRITE operation will not generate completion entry on Responder side,<br>
I am following the technique like polling on the last byte of receive buffer.<br>
<br>
Steps i followed are:<br>
1. kmalloc is used for memory allocation,<br>
2. ib_reg_phys_mr is used for memory registration,<br>
3. RDMA WRITE is requested on initiator side and the completion entry is success,<br>
4. Responder is polling on last byte of receive buffer to be set,<br>
but Responder is not able to find the buffer updation and stuck in infinite loop.<br>
<br>
Please help me in solving the above mentioned problem. Let me know if<br>
something is missed. <br>
<br>
The same approach i.e. polling on last byte of receive buffer works for me in<br>
user space(uverbs) RDMA_WRITE operation.<br>
<br>
My host machine is running Linux kernel 2.6.18.<br>
<br>
Any reference or web links will be useful. <br>
<br>
Thanks & Regards<br>
Jagadeesh.<o:p></o:p></p>
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