fi_sockets(7)                  Libfabric v1.22.0                 fi_sockets(7)

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.

Libfabric Programmer's Manual     2022-12-09                     fi_sockets(7)