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Copyright(c) 2015 Intel Corporation.
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/* Copyright (c) 2003-2014 Intel Corporation. All rights reserved. */
#ifndef PSM2_AM_H
#define PSM2_AM_H
#include <stddef.h>
#include <stdint.h>
#include <psm2.h>
#ifdef __cplusplus
extern "C" {
#endif
/*!
* @file psm2_am.h
* @brief PSM2 Active Message.
*
* @page psm2_am Active Message Interface
*
* PSM2 implements an Active Message (AM) component that lives alongside the
* Matched Queues (MQ) component. The active message interface essentially
* provides a remote procedure call mechanism. A PSM2 process can generate a
* request to run an active message handler on a remote PSM2 process
* identified by its end-point address (epaddr). End-point address values
* are returned by PSM2 when connecting end-points using the psm2_ep_connect()
* function.
*
* An AM handler may make local state updates, and may generate at most
* one reply to be returned to the original requestor. This reply will cause
* a handler to be run on that requestor. The requestor handler may make
* local state updates but is not allowed to reply nor request in that handler
* context. A request or reply can convey a small number of in-line arguments
* plus a short amount of data. A tight bound is placed on the number of
* in-line arguments to allow them to be packed into a header. A bound is
* placed on the size of the data payload so that the request or reply can
* be sent as a single packet within the MTU of the underlying communication
* transport. Longer payloads must be synthesized on top of the provided
* short request/reply mechanism by fragmentation and reassembly, or
* transported by some other means.
*
* Handlers are run in the process context of the targeted PSM2 process,
* either in its main thread of execution or in a progress thread. A handler
* may therefore be executed concurrently with the main thread of execution
* of the PSM2 process. PSM2 ensures that its own state is protected against this
* concurrent execution. However, a handler must make its own arrangements to
* protect its own state. Alternatively, the PSM2 progress thread can be
* disabled using the PSM2_RCVTHREAD environment variable if this is too
* onerous for the handler.
*
* PSM2 has an active progress model and requires that the PSM2 library is
* called in order to make progress. This can be achieved using the psm2_poll()
* function. A PSM2 implementatation may provide passive progress through some
* other mechanism (e.g. a receive thread), but a PSM2 consumer must not assume
* this and must arrange to make active progress through calls into the PSM
* library. Note that the PSM2 AM interface is not MTsafe, same as the other PSM
* interfaces, and that MTsafety must be provided by the consumer if required.
*
* The order in which AM requests are issued by an initiator to a particular
* target defines the order in which those AM requests will be executed on
* that target. Therefore the AM implementation will maintain the order
* of handler executions on a flow, and this also applies when progress
* threads are used. For multiple initiators issuing requests to a particular
* target, the handler executions will be interleaved in some sequentially
* consistent ordering.
*/
/*! @defgroup am PSM2 Active Message
*
* @{
*/
/** @brief Datatype for an index representing an active message handler */
typedef uint32_t psm2_handler_t;
/** @brief Datatype for a token for an active message handler.*/
typedef void *psm2_am_token_t;
/* PSM2 AM flags
* These flags may be combined using bitwise-or.
*/
#define PSM2_AM_FLAG_NONE 0 /**< No other PSM2 AM flags are needed. */
#define PSM2_AM_FLAG_ASYNC 1 /**< No need to copy source data. */
#define PSM2_AM_FLAG_NOREPLY 2 /**< The handler for this AM request is
guaranteed not to generate a reply. */
/** @brief The psm2_amarg type represents the type of an AM argument. This is
* a 64-bit type and is broken down into four 16-bit fields, two 32-bit
* fields or one 64-bit field for the convenience of code using the PSM2 AM
* interface.
*/
typedef
struct psm2_amarg {
union {
struct {
uint16_t u16w3;
uint16_t u16w2;
uint16_t u16w1;
uint16_t u16w0;
};
struct {
uint32_t u32w1;
uint32_t u32w0;
};
uint64_t u64w0;
uint64_t u64;
};
} psm2_amarg_t;
/** @brief The AM handler function type
*
* psm2_am_handler_fn_t is the datatype for an AM handler. PSM2 AM will call-back
* into an AM handler using this function prototype. The parameters and result
* of these handler functions are described here.
*
* @param[in] token This is an opaque token value passed into a handler.
* A request handler may send at most one reply back to the
* original requestor, and must pass this value as the token
* parameter to the psm2_am_reply_short() function. A reply
* handler is also passed a token value, but must not attempt
* to reply.
* @param[in] args A pointer to the arguments provided to this handler.
* @param[in] nargs The number of arguments.
* @param[in] src A pointer to the data payload provided to this handler.
* @param[in] len The length of the data payload in bytes.
*
* @returns 0 The handler should always return a result of 0.
*/
typedef
int (*psm2_am_handler_fn_t) (psm2_am_token_t token,
psm2_amarg_t *args, int nargs,
void *src, uint32_t len);
/** @brief The AM handler function type with caller context
*
* psm2_am_handler_2_fn_t is the datatype for an AM handler that
* includes a user context. PSM2 AM will call-back into an AM handler using
* this function prototype. The parameters and result
* of these handler functions are described here.
*
* @param[in] token This is an opaque token value passed into a handler.
* A request handler may send at most one reply back to the
* original requestor, and must pass this value as the token
* parameter to the psm2_am_reply_short() function. A reply
* handler is also passed a token value, but must not attempt
* to reply.
* @param[in] args A pointer to the arguments provided to this handler.
* @param[in] nargs The number of arguments.
* @param[in] src A pointer to the data payload provided to this handler.
* @param[in] len The length of the data payload in bytes.
* @param[in] hctx The user context pointer provided at handler registration.
*
* @returns 0 The handler should always return a result of 0.
*/
typedef
int (*psm2_am_handler_2_fn_t) (psm2_am_token_t token,
psm2_amarg_t *args, int nargs,
void *src, uint32_t len, void *hctx);
/** @brief Type for a completion call-back handler.
*
* A completion handler can be specified to give a call-back on the initiation
* side that an AM request or reply has completed on the target side. The
* call-back has a context pointer which is provided along with the call-back
* function pointer when the initiator generates the request or reply. This
* approach will typically give higher performance than using an AM request or
* reply to achieve the same effect, though note that no additional information
* can be passed from the target side back to the initiator side with the
* completion handler approach.
*
* @param[in] context A context pointer.
* @returns void This handler has no return result.
*/
typedef
void (*psm2_am_completion_fn_t) (void *context);
/** @brief Register AM call-back handlers at the specified end-point.
*
* This function is used to register an array of handlers, and may be called
* multiple times to register additonal handlers. The maximum number of
* handlers that can be registered is limited to the max_handlers value
* returned by psm2_am_get_parameters(). Handlers are associated with a PSM
* end-point. The handlers are allocated index numbers in the the handler table
* for that end-point. The allocated index for the handler function in
* handlers[i] is returned in handlers_idx[i] for i in (0, num_handlers]. These
* handler index values are used in the psm2_am_request_short() and
* psm2_am_reply_short() functions.
*
* @param[in] ep End-point value
* @param[in] handlers Array of handler functions
* @param[in] num_handlers Number of handlers (sizes the handlers and
* handlers_idx arrays)
* @param[out] handlers_idx Used to return handler index mapping table
*
* @returns PSM2_OK Indicates success
* @returns PSM2_EP_NO_RESOURCES Insufficient slots in the AM handler table
*/
psm2_error_t psm2_am_register_handlers(psm2_ep_t ep,
const psm2_am_handler_fn_t *
handlers, int num_handlers,
int *handlers_idx);
/** @brief Register AM call-back handlers at the specified end-point.
*
* This function is used to register an array of handlers, and may be called
* multiple times to register additonal handlers. The maximum number of
* handlers that can be registered is limited to the max_handlers value
* returned by psm2_am_get_parameters(). Handlers are associated with a PSM
* end-point. The handlers are allocated index numbers in the the handler table
* for that end-point. The allocated index for the handler function in
* handlers[i] is returned in handlers_idx[i] for i in (0, num_handlers]. These
* handler index values are used in the psm2_am_request_short() and
* psm2_am_reply_short() functions.
*
* @param[in] ep End-point value
* @param[in] handlers Array of handler functions
* @param[in] num_handlers Number of handlers (sizes the handlers and
* handlers_idx arrays)
* @param[in] hctx Array of void* pointers to a user contexts for identifying the
* target ep that registered these handlers.
* @param[out] handlers_idx Used to return handler index mapping table
*
* @returns PSM2_OK Indicates success
* @returns PSM2_EP_NO_RESOURCES Insufficient slots in the AM handler table
*/
psm2_error_t psm2_am_register_handlers_2(psm2_ep_t ep,
const psm2_am_handler_2_fn_t *
handlers, int num_handlers,
void **hctx,
int *handlers_idx);
/** @brief Unregister all AM call-back handlers for the specific end-point.
*
* This function is used to unregister all AM handlers registered to the
* specified end-point.
*
* @param[in] ep End-point value
*
*/
void psm2_am_unregister_handlers(psm2_ep_t ep);
/** @brief Generate an AM request.
*
* This function generates an AM request causing an AM handler function to be
* called in the PSM2 process associated with the specified end-point address.
* The number of arguments is limited to max_nargs and the payload length in
* bytes to max_request_short returned by the psm2_am_get_parameters() function.
* If arguments are not required, set the number of arguments to 0 and the
* argument pointer will not be dereferenced. If payload is not required, set
* the payload size to 0 and the payload pointer will not be dereferenced.
*
* Optionally a completion function and completion context pointer can be
* provided, and a local call-back will be made to that function passing in
* that context pointer once remote execution of the handler has completed. If
* the completion call-back is not required, the handler should be specified as
* NULL and the pointer value will not be used.
*
* The allowed flags are any combination of the following combined with
* bitwise-or:
* PSM2_AM_FLAG_NONE - No flags
* PSM2_AM_FLAG_ASYNC - Indicates no need to copy source data
* PSM2_AM_FLAG_NOREPLY - The handler for this AM request is guaranteed not to
* generate a reply
*
* The PSM2 AM implementation will not dereference the args pointer after return
* from this function. If PSM2_AM_FLAG_ASYNC is not provided, the PSM2 AM
* implementation will not dereference the src pointer after return from this
* function. This may require the implementation to take a copy of the payload
* if the request cannot be issued immediately. However, if PSM2_AM_FLAG_ASYNC
* is provided then a copy will not be taken and the PSM2 AM implementation
* retains ownership of the payload src memory until the request is locally
* complete. Local completion can be determined using the completion handler
* call-back, or through an AM handler associated with an AM reply.
*
* The PSM2_AM_FLAG_NOREPLY flag indicates ahead of time to the AM handler that
* a reply will not be generated. Use of this flag is optional, but it may
* enable a performance optimization in this case by indicating that reply
* state is not required.
*
* @param[in] epaddr End-point address to run handler on
* @param[in] handler Index of handler to run
* @param[in] args Array of arguments to be provided to the handler
* @param[in] nargs Number of arguments to be provided to the handler
* @param[in] src Pointer to the payload to be delivered to the handler
* @param[in] len Length of the payload in bytes
* @param[in] flags These are PSM2 AM flags and may be combined together with
* bitwise-or
* @param[in] completion_fn The completion function to called locally when
* remote handler is complete
* @param[in] completion_ctxt User-provided context pointer to be passed to the
* completion handler
*
* @returns PSM2_OK indicates success.
*/
psm2_error_t
psm2_am_request_short(psm2_epaddr_t epaddr, psm2_handler_t handler,
psm2_amarg_t *args, int nargs, void *src,
size_t len, int flags,
psm2_am_completion_fn_t completion_fn,
void *completion_ctxt);
/** @brief Generate an AM reply.
*
* This function may only be called from an AM handler called due to an AM
* request. If the AM request uses the PSM2_AM_FLAG_NOREPLY flag, the AM
* handler must not call this function. Otherwise, the AM request handler may
* call psm2_am_reply_short() at most once, and must pass in the token value
* that it received in its own handler call-back.
*
* This function generates an AM reply causing an AM handler function to be
* called in the PSM2 process associated with the specified end-point address.
* The number of arguments is limited to max_nargs and the payload length in
* bytes to max_reply_short returned by the psm2_am_get_parameters() function.
* If arguments are not required, set the number of arguments to 0 and the
* argument pointer will not be dereferenced. If payload is not required, set
* the payload size to 0 and the payload pointer will not be dereferenced.
*
* Optionally a completion function and completion context pointer can be
* provided, and a local call-back will be made to that function passing in
* that context pointer once remote execution of the handler has completed. If
* the completion call-back is not required, the handler should be specified as
* NULL and the pointer value will not be used.
*
* The allowed flags are any combination of the following combined with
* bitwise-or:
* PSM2_AM_FLAG_NONE - No flags
* PSM2_AM_FLAG_ASYNC - Indicates no need to copy source data
*
* The PSM2 AM implementation will not dereference the args pointer after return
* from this function. If PSM2_AM_FLAG_ASYNC is not provided, the PSM2 AM
* implementation will not dereference the src pointer after return from this
* function. This may require the implementation to take a copy of the payload
* if the reply cannot be issued immediately. However, if PSM2_AM_FLAG_ASYNC is
* provided then a copy will not be taken and the PSM2 AM implementation retains
* ownership of the payload src memory until the reply is locally complete.
* Local completion can be determined using the completion handler call-back.
*
* @param[in] token Token value provided to the AM handler that is generating
* the reply.
* @param[in] handler Index of handler to run
* @param[in] args Array of arguments to be provided to the handler
* @param[in] nargs Number of arguments to be provided to the handler
* @param[in] src Pointer to the payload to be delivered to the handler
* @param[in] len Length of the payload in bytes
* @param[in] flags These are PSM2 AM flags and may be combined together with
* bitwise-or
* @param[in] completion_fn The completion function to called locally when
* remote handler is complete
* @param[in] completion_ctxt User-provided context pointer to be passed to the
* completion handler
*
* @returns PSM2_OK indicates success.
*/
psm2_error_t
psm2_am_reply_short(psm2_am_token_t token, psm2_handler_t handler,
psm2_amarg_t *args, int nargs, void *src,
size_t len, int flags,
psm2_am_completion_fn_t completion_fn,
void *completion_ctxt);
/** @brief Return the source end-point address for a token.
*
* This function is used to obtain the epaddr object representing the message
* initiator from a token passed by PSM2 to a message handler.
*
* @param[in] token Token value provided to the AM handler that is generating
* the reply.
* @param[out] epaddr_out Pointer to the where the epaddr should be returned.
*
* @returns PSM2_OK indicates success.
* @returns PSM2_PARAM_ERR token is invalid or epaddr_out is NULL.
*/
psm2_error_t psm2_am_get_source(psm2_am_token_t token,
psm2_epaddr_t *epaddr_out);
/** @brief AM parameters
*
* This structure is used to return PSM2 AM implementation-specific parameter
* values back to the caller of the psm2_am_get_parameters() function. This
* API also specifies the minimum values for these parameters that an
* implementation must at least provide:
* max_handlers >= 64,
* max_nargs >= 2,
* max_request_short >= 256 and
* max_reply_short >= 256.
*/
struct psm2_am_parameters {
/** Maximum number of handlers that can be registered. */
uint32_t max_handlers;
/** Maximum number of arguments to an AM handler. */
uint32_t max_nargs;
/** Maximum number of bytes in a request payload. */
uint32_t max_request_short;
/** Maximum number of bytes in a reply payload. */
uint32_t max_reply_short;
};
/** @brief Get the AM parameter values
*
* This function retrieves the implementation-specific AM parameter values for
* the specified end-point.
*
* @param[in] ep The end-point value returned by psm2_ep_open().
* @param[out] parameters Pointer to the struct where the parameters will be
* returned.
* @param[in] sizeof_parameters_in The size in bytes of the struct provided by
* the caller.
* @param[out] sizeof_parameters_out The size in bytes of the struct returned
* by PSM.
*
* @returns PSM2_OK indicates success.
*/
psm2_error_t
psm2_am_get_parameters(psm2_ep_t ep,
struct psm2_am_parameters *parameters,
size_t sizeof_parameters_in,
size_t *sizeof_parameters_out);
/*! @} */
#ifdef __cplusplus
} /* extern "C" */
#endif
#endif