NAME

       fi_sockets - The Sockets Fabric Provider

OVERVIEW

       The  sockets provider is being deprecated in favor of the tcp, udp, and utility providers.
       Further work on the sockets provider will be minimal.  Most  applications  should  instead
       use the tcp provider instead.

       The  sockets  provider  is  a general purpose provider that can be used on any system that
       supports TCP sockets.  The provider is not intended to  provide  performance  improvements
       over  regular  TCP  sockets,  but  rather  to  allow  developers to write, test, and debug
       application code even on platforms that do not have high-performance fabric hardware.  The
       sockets provider supports all libfabric provider requirements and interfaces.

SUPPORTED FEATURES

       The  sockets  provider  supports  all  the  features  defined  for the libfabric API.  Key
       features include:

       Endpoint types
              The provider supports all endpoint types: FI_EP_MSG, FI_EP_RDM, and FI_EP_DGRAM.

       Endpoint capabilities
              The following data transfer interface  is  supported  for  a  all  endpoint  types:
              fi_msg.   Additionally,  these  interfaces  are  supported  for  reliable endpoints
              (FI_EP_MSG and FI_EP_RDM): fi_tagged, fi_atomic, and fi_rma.

       Modes  The sockets provider  supports  all  operational  modes  including  FI_CONTEXT  and
              FI_MSG_PREFIX.

       Progress
              Sockets  provider  supports  both  FI_PROGRESS_AUTO  and FI_PROGRESS_MANUAL, with a
              default set to auto.  When progress is set to auto, a  background  thread  runs  to
              ensure that progress is made for asynchronous requests.

LIMITATIONS

       Sockets  provider  attempts  to emulate the entire API set, including all defined options.
       In order to support development on a wide range of systems, it  is  implemented  over  TCP
       sockets.   As  a  result,  the  performance  numbers are lower compared to other providers
       implemented over  high-speed  fabric,  and  lower  than  what  an  application  might  see
       implementing to sockets directly.

       Does not support FI_ADDR_STR address format.

RUNTIME PARAMETERS

       The sockets provider checks for the following environment variables -

       FI_SOCKETS_PE_WAITTIME
              An  integer  value  that  specifies how many milliseconds to spin while waiting for
              progress in FI_PROGRESS_AUTO mode.

       FI_SOCKETS_CONN_TIMEOUT
              An integer value that specifies how many milliseconds to wait  for  one  connection
              establishment.

       FI_SOCKETS_MAX_CONN_RETRY
              An  integer  value  that  specifies  the number of socket connection retries before
              reporting as failure.

       FI_SOCKETS_DEF_CONN_MAP_SZ
              An integer to specify the default connection map size.

       FI_SOCKETS_DEF_AV_SZ
              An integer to specify the default address vector size.

       FI_SOCKETS_DEF_CQ_SZ
              An integer to specify the default completion queue size.

       FI_SOCKETS_DEF_EQ_SZ
              An integer to specify the default event queue size.

       FI_SOCKETS_DGRAM_DROP_RATE
              An integer value to  specify  the  drop  rate  of  dgram  frame  when  endpoint  is
              FI_EP_DGRAM.  This is for debugging purpose only.

       FI_SOCKETS_PE_AFFINITY
              If  specified,  progress thread is bound to the indicated range(s) of Linux virtual
              processor ID(s).  This option is currently not supported on OS X.  The usage  is  -
              id_start[-id_end[:stride]][,].

       FI_SOCKETS_KEEPALIVE_ENABLE
              A boolean to enable the keepalive support.

       FI_SOCKETS_KEEPALIVE_TIME
              An  integer  to specify the idle time in seconds before sending the first keepalive
              probe.  Only relevant if FI_SOCKETS_KEEPALIVE_ENABLE is enabled.

       FI_SOCKETS_KEEPALIVE_INTVL
              An integer to specify the time in  seconds  between  individual  keepalive  probes.
              Only relevant if FI_SOCKETS_KEEPALIVE_ENABLE is enabled.

       FI_SOCKETS_KEEPALIVE_PROBES
              An  integer  to specify the maximum number of keepalive probes sent before dropping
              the connection.  Only relevant if FI_SOCKETS_KEEPALIVE_ENABLE is enabled.

       FI_SOCKETS_IFACE
              The prefix or the name of the network interface (default: any)

LARGE SCALE JOBS

       For large scale runs one can use these environment variables to set the default parameters
       e.g. size  of  the  address  vector(AV),  completion queue (CQ), connection map etc.  that
       satisfies the requirement of the particular benchmark.   The  recommended  parameters  for
       large    scale    runs    are    FI_SOCKETS_MAX_CONN_RETRY,    FI_SOCKETS_DEF_CONN_MAP_SZ,
       FI_SOCKETS_DEF_AV_SZ, FI_SOCKETS_DEF_CQ_SZ, FI_SOCKETS_DEF_EQ_SZ.

SEE ALSO

       fabric(7), fi_provider(7), fi_getinfo(3)

AUTHORS

       OpenFabrics.