James, Mellanox InfiniScale III switch chip does support 4K MTU as stated in the product brief. However it requires special FW settings that might or might not be available from/supported by particular switch system vendor.
Boris Shpolyansky Sr. Member of Technical Staff, Applications Mellanox Technologies Inc. 350 Oakmead Parkway Sunnyvale, CA 94085 Tel.: (408) 916 0014 Fax: (408) 970 3403 Cell: (408) 834 9365 www.mellanox.com -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of James Lentini Sent: Thursday, January 08, 2009 7:25 AM To: Hal Rosenstock Cc: [email protected] Subject: Re: [ofa-general] Configuring a 4 KB InfniBand link MTU On Wed, 7 Jan 2009, Hal Rosenstock wrote: <snip> > If the switch ports support a 4K MTU cap, it needs to be advertised > (via the PortInfo response). That's what needs fixing if possible > rather than some SM policy. Without an MTUCap of 4K on both sides of > the link, an SM cannot set NeighborMTU to 4K. Thanks Hal. I'll do some more research on my switch to see if it is indeed capable of a 4 KB MTU. This datasheet on the MT47396 lists a 4 KB MTU as one of its features: http://www.mellanox.com/related-docs/prod_silicon/InfiniScaleIII.pdf Perhaps the version of the chip I have doesn't support a 4 KB MTU or the switch hardware/firmware doesn't support it. > > # smpquery portinfo 2 1 > > # Port info: Lid 2 port 1 > > Mkey:............................0x0000000000000000 > > GidPrefix:.......................0x0000000000000000 > > Lid:.............................0x0000 > > SMLid:...........................0x0000 > > CapMask:.........................0x0 > > DiagCode:........................0x0000 > > MkeyLeasePeriod:.................0 > > LocalPort:.......................1 > > LinkWidthEnabled:................4X > > LinkWidthSupported:..............1X or 4X > > LinkWidthActive:.................4X > > LinkSpeedSupported:..............2.5 Gbps or 5.0 Gbps > > LinkState:.......................Active > > PhysLinkState:...................LinkUp > > LinkDownDefState:................Polling > > ProtectBits:.....................0 > > LMC:.............................0 > > LinkSpeedActive:.................5.0 Gbps > > LinkSpeedEnabled:................2.5 Gbps or 5.0 Gbps > > NeighborMTU:.....................2048 > > SMSL:............................0 > > VLCap:...........................VL0-7 > > InitType:........................0x00 > > VLHighLimit:.....................0 > > VLArbHighCap:....................8 > > VLArbLowCap:.....................8 > > InitReply:.......................0x00 > > MtuCap:..........................2048 > > VLStallCount:....................7 > > HoqLife:.........................18 > > OperVLs:.........................VL0-7 > > PartEnforceInb:..................0 > > PartEnforceOutb:.................0 > > FilterRawInb:....................0 > > FilterRawOutb:...................0 > > MkeyViolations:..................0 > > PkeyViolations:..................0 > > QkeyViolations:..................0 > > GuidCap:.........................0 > > ClientReregister:................0 > > SubnetTimeout:...................0 > > RespTimeVal:.....................0 > > LocalPhysErr:....................15 > > OverrunErr:......................15 > > MaxCreditHint:...................0 > > RoundTrip:.......................0 > > > > and I confirmed that the switch had a MT47396: > > > > # smpquery nodeinfo 2 > > # Node info: Lid 2 > > BaseVers:........................1 > > ClassVers:.......................1 > > NodeType:........................Switch > > NumPorts:........................24 > > SystemGuid:......................0x0005ad03011df356 > > Guid:............................0x0005ad00001df356 > > PortGuid:........................0x0005ad00001df356 > > PartCap:.........................8 > > DevId:...........................0xb924 > > Revision:........................0x000001a1 > > LocalPort:.......................1 > > VendorId:........................0x0005ad > > _______________________________________________ > > general mailing list > > [email protected] > > http://lists.openfabrics.org/cgi-bin/mailman/listinfo/general > > > > To unsubscribe, please visit http://openib.org/mailman/listinfo/openib-general > > > _______________________________________________ general mailing list [email protected] http://lists.openfabrics.org/cgi-bin/mailman/listinfo/general To unsubscribe, please visit http://openib.org/mailman/listinfo/openib-general _______________________________________________ general mailing list [email protected] http://lists.openfabrics.org/cgi-bin/mailman/listinfo/general To unsubscribe, please visit http://openib.org/mailman/listinfo/openib-general
