<html><body><div style="color:#000; background-color:#fff; font-family:times new roman, new york, times, serif;font-size:12pt"><div><span>We have a cluster of 16 nodes. And rest all 15 nodes shows the same value i.e. 10 Gb/sec (4X) except this node <br></span></div><div><br></div> <div style="font-family: times new roman,new york,times,serif; font-size: 12pt;"> <div style="font-family: times new roman,new york,times,serif; font-size: 12pt;"> <div dir="ltr"> <font face="Arial" size="2"> <hr size="1"> <b><span style="font-weight: bold;">From:</span></b> Hal Rosenstock <hal@dev.mellanox.co.il><br> <b><span style="font-weight: bold;">To:</span></b> Mahesh Chaudhari <mahesh.chaudhari@ymail.com> <br><b><span style="font-weight: bold;">Cc:</span></b> "ewg@lists.openfabrics.org" <ewg@lists.openfabrics.org> <br> <b><span style="font-weight: bold;">Sent:</span></b> Wednesday, 20 February 2013 5:24 PM<br> <b><span style="font-weight:
bold;">Subject:</span></b> Re: [ewg] strange value of IB port rate<br> </font> </div> <br>On 2/20/2013 6:51 AM, Mahesh Chaudhari wrote:<br>> Hi All,<br>> i have Mellanox dual port IB card installed in m/c<br>> when i do :<br>> "cat /sys/class/infiniband/mthca0/ports/1/rate "<br>> it shows 20 Gb/sec (4X DDR)<br>> <br>> while on port2<br>> " cat /sys/class/infiniband/mthca0/ports/2/rate "<br>> it shows 8.5 Gb/sec (4X)<br>> <br>> when i looked at source code, i found a equation to calculate rate :<br>> <br>> rate = 25 *<br>> ib_width_enum_to_int(attr.active_width) * attr.active_speed;<br>> <br>>
return sprintf(buf, "%d%s Gb/sec (%dX%s)\n",<br>> rate / 10, rate % 10 ? ".5" : "",<br>> ib_width_enum_to_int(attr.active_width), speed);<br>> <br>> <br>> where <br>> ib_width_enum_to_int(attr.active_width) = 1 | 4 |8 |12 | -1(error)<br>> attr.active_speed = 1 | 2 | 4 <br>> <br>> <br>> i am wondering, how could it possible to get such an odd value (8.5<br>> Gbps)<br>> <br>> /usr/ofed/sbin/ibstatus utility also shows :<br>>
<br>> Infiniband device 'mthca0' port 1 status:<br>> default gid: fe80:0000:0000:0000:001a:4bff:ff0c:96e5<br>> base lid: 0x6<br>> sm lid: 0x1<br>> state: 4: ACTIVE<br>> phys state: 5: LinkUp<br>> rate: 20 Gb/sec (4X DDR)<br>> link_layer: InfiniBand<br>> <br>> Infiniband device 'mthca0' port 2 status:<br>> default gid: fe80:0000:0000:0000:001a:4bff:ff0c:96e6<br>> base lid: 0x0<br>> sm lid: 0x0<br>> state: 1: DOWN<br>> phys state: 2: Polling<br>> rate: 8.5 Gb/sec
(4X)<br>> link_layer: InfiniBand<br>> <br>> <br>> <br>> <br>> Any Clue ???<br><br>In the case of DOWN ports, rate is meaningless and should be ignored.<br><br>-- Hal<br><br>> <br>> <br>> _______________________________________________<br>> ewg mailing list<br>> <a ymailto="mailto:ewg@lists.openfabrics.org" href="mailto:ewg@lists.openfabrics.org">ewg@lists.openfabrics.org</a><br>> <a href="http://lists.openfabrics.org/cgi-bin/mailman/listinfo/ewg" target="_blank">http://lists.openfabrics.org/cgi-bin/mailman/listinfo/ewg</a><br><br><br><br> </div> </div> </div></body></html>