Provided by: libfabric1_1.5.3-1_amd64 
NAME
fi_sockets - The Sockets Fabric Provider
OVERVIEW
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_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]][,].
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 requriment 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.