fi_rxm(7)

1fi_rxm(7)                      Libfabric v1.6.1                      fi_rxm(7)
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NAME

6       fi_rxm - The RxM (RDM over MSG) Utility Provider
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OVERVIEW

9       The  RxM  provider  (ofi_rxm)  is an utility provider that supports RDM
10       endpoint emulated over MSG endpoint of a core provider.
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REQUIREMENTS

13       RxM provider requires the core provider to support the  following  fea‐
14       tures:
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16       · MSG endpoints (FI_EP_MSG)
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18       · RMA read/write (FI_RMA)
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20       · FI_OPT_CM_DATA_SIZE of at least 24 bytes
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SUPPORTED FEATURES

23       The  RxM provider currently supports FI_MSG, FI_TAGGED and FI_RMA capa‐
24       bilities.
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26       Endpoint types : The provider supports only FI_EP_RDM.
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28       Endpoint capabilities : The following data transfer interface  is  sup‐
29       ported: FI_MSG, FI_TAGGED, FI_RMA.
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31       Progress : The RxM provider supports FI_PROGRESS_AUTO.
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33       Addressing Formats : FI_SOCKADDR, FI_SOCKADDR_IN
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35       Memory  Region  :  FI_MR_VIRT_ADDR,  FI_MR_ALLOCATED, FI_MR_PROV_KEY MR
36       mode bits would be required from the app  in  case  the  core  provider
37       requires it.
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LIMITATIONS

40       When  using  RxM  provider,  some  limitations  from the underlying MSG
41       provider could also show up.  Please refer  to  the  corresponding  MSG
42       provider man pages to find about those limitations.
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44   Unsupported features
45       RxM provider does not support the following features:
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47       · op_flags: FI_FENCE.
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49       · FI_ATOMIC
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51       · Scalable endpoints
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53       · Shared contexts
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55       · FABRIC_DIRECT
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57       · FI_MR_SCALABLE
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59       · Authorization keys
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61       · Application error data buffers
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63       · Multicast
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65       · FI_ADDR_STR, FI_SYNC_ERR
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67       · Reporting unknown source addr data as part of completions
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69       · Triggered operations
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71   Auto progress
72       When sending large messages, an app doing an sread or waiting on the CQ
73       file descriptor may not get a completion  when  reading  the  CQ  after
74       being  woken  up from the wait.  The app has to do sread or wait on the
75       file descriptor again.
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RUNTIME PARAMETERS

78       The ofi_rxm provider checks for the following environment variables.
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80       FI_OFI_RXM_BUFFER_SIZE : Defines the  transmit  buffer  size  /  inject
81       size.   Messages  of  size  less  than this would be transmitted via an
82       eager protocol and those above would be transmitted  via  a  rendezvous
83       protocol.   Transmit  data  would  be  copied up to this size (default:
84       ~16k).
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86       FI_OFI_RXM_COMP_PER_PROGRESS  :  Defines  the  maximum  number  of  MSG
87       provider  CQ  entries (default: 1) that would be read per progress (RxM
88       CQ read).
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AUTHORS

94       OpenFabrics.
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98Libfabric Programmer's Manual     2018-02-19                         fi_rxm(7)