See comments inline. In general I like this, as it does seem clean and minimal.
On Mon, May 18, 2015 at 5:03 PM, Ola Liljedahl <[email protected]> wrote: > As promised, here is my first attempt at a standalone API for IPC - inter > process communication in a shared nothing architecture (message passing > between processes which do not share memory). > > Currently all definitions are in the file ipc.h but it is possible to > break out some message/event related definitions (everything from > odp_ipc_sender) in a separate file message.h. This would mimic the > packet_io.h/packet.h separation. > > The semantics of message passing is that sending a message to an endpoint > will always look like it succeeds. The appearance of endpoints is > explicitly > notified through user-defined messages specified in the odp_ipc_resolve() > call. Similarly, the disappearance (e.g. death or otherwise lost > connection) > is also explicitly notified through user-defined messages specified in the > odp_ipc_monitor() call. The send call does not fail because the addressed > endpoints has disappeared. > > Messages (from endpoint A to endpoint B) are delivered in order. If message > N sent to an endpoint is delivered, then all messages <N have also been > delivered. Message delivery does not guarantee actual processing by the > recipient. End-to-end acknowledgements (using messages) should be used if > this guarantee is important to the user. > > IPC endpoints can be seen as interfaces (taps) to an internal reliable > multidrop network where each endpoint has a unique address which is only > valid for the lifetime of the endpoint. I.e. if an endpoint is destroyed > and then recreated (with the same name), the new endpoint will have a > new address (eventually endpoints addresses will have to be recycled but > not for a very long time). Endpoints names do not necessarily have to be > unique. > > Signed-off-by: Ola Liljedahl <[email protected]> > --- > (This document/code contribution attached is provided under the terms of > agreement LES-LTM-21309) > > include/odp/api/ipc.h | 261 > ++++++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 261 insertions(+) > create mode 100644 include/odp/api/ipc.h > > diff --git a/include/odp/api/ipc.h b/include/odp/api/ipc.h > new file mode 100644 > index 0000000..3395a34 > --- /dev/null > +++ b/include/odp/api/ipc.h > @@ -0,0 +1,261 @@ > +/* Copyright (c) 2015, Linaro Limited > + * All rights reserved. > + * > + * SPDX-License-Identifier: BSD-3-Clause > + */ > + > + > +/** > + * @file > + * > + * ODP IPC API > + */ > + > +#ifndef ODP_API_IPC_H_ > +#define ODP_API_IPC_H_ > + > +#ifdef __cplusplus > +extern "C" { > +#endif > + > +/** @defgroup odp_ipc ODP IPC > + * @{ > + */ > + > +/** > + * @typedef odp_ipc_t > + * ODP IPC handle > + */ > + > +/** > + * @typedef odp_ipc_msg_t > + * ODP IPC message handle > + */ > + > + > +/** > + * @def ODP_IPC_ADDR_SIZE > + * Size of the address of an IPC endpoint > + */ > + > +/** > + * Create IPC endpoint > + * > + * @param name Name of local IPC endpoint > + * @param pool Pool for incoming messages > Should document the type of the pool being used. Since the object type for IPC channels is odp_ipc_msg_t, that would imply that this should be a new pool type (ODP_POOL_IPC or ODP_POOL_IPC_MSG) to buffer these objects. > + * > + * @return IPC handle on success > + * @retval ODP_IPC_INVALID on failure and errno set > + */ > +odp_ipc_t odp_ipc_create(const char *name, odp_pool_t pool); > + > +/** > + * Destroy IPC endpoint > + * > + * @param ipc IPC handle > + * > + * @retval 0 on success > + * @retval <0 on failure > + */ > +int odp_ipc_destroy(odp_ipc_t ipc); > + > +/** > + * Set the default input queue for an IPC endpoint > + * > + * @param ipc IPC handle > + * @param queue Queue handle > + * > + * @retval 0 on success > + * @retval <0 on failure > + */ > +int odp_ipc_inq_setdef(odp_ipc_t ipc, odp_queue_t queue); > + > +/** > + * Remove the default input queue > + * > + * Remove (disassociate) the default input queue from an IPC endpoint. > + * The queue itself is not touched. > + * > + * @param ipc IPC handle > + * > + * @retval 0 on success > + * @retval <0 on failure > + */ > +int odp_ipc_inq_remdef(odp_ipc_t ipc); > + > +/** > + * Resolve endpoint by name > + * > + * Look up an existing or future endpoint by name. > + * When the endpoint exists, return the specified message with the > endpoint > + * as the sender. > + * > + * @param ipc IPC handle > + * @param name Name to resolve > + * @param msg Message to return > + */ > +void odp_ipc_resolve(odp_ipc_t ipc, > + const char *name, > + odp_ipc_msg_t msg); > Shouldn't this be odp_ipc_lookup() for consistency with the other named lookup APIs? > + > +/** > + * Monitor endpoint > + * > + * Monitor an existing (potentially already dead) endpoint. > + * When the endpoint is dead, return the specified message with the > endpoint > + * as the sender. > + * > + * Unrecognized or invalid endpoint addresses are treated as dead > endpoints. > + * > + * @param ipc IPC handle > + * @param addr Address of monitored endpoint > + * @param msg Message to return > + */ > +void odp_ipc_monitor(odp_ipc_t ipc, > + const uint8_t addr[ODP_IPC_ADDR_SIZE], > + odp_ipc_msg_t msg); > + > +/** > + * Send message > + * > + * Send a message to an endpoint (which may already be dead). > + * Message delivery is ordered and reliable. All (accepted) messages will > be > + * delivered up to the point of endpoint death or lost connection. > + * Actual reception and processing is not guaranteed (use end-to-end > + * acknowledgements for that). > + * Monitor the remote endpoint to detect death or lost connection. > + * > + * @param ipc IPC handle > + * @param msg Message to send > + * @param addr Address of remote endpoint > + * > + * @retval 0 on success > + * @retval <0 on error > + */ > +int odp_ipc_send(odp_ipc_t ipc, > + odp_ipc_msg_t msg, > + const uint8_t addr[ODP_IPC_ADDR_SIZE]); > + > +/** > + * Get address of sender (source) of message > + * > + * @param msg Message handle > + * @param addr Address of sender endpoint > + */ > +void odp_ipc_sender(odp_ipc_msg_t msg, > + uint8_t addr[ODP_IPC_ADDR_SIZE]); > + > +/** > + * Message data pointer > + * > + * Return a pointer to the message data > + * > + * @param msg Message handle > + * > + * @return Pointer to the message data > + */ > +void *odp_ipc_data(odp_ipc_msg_t msg); > + > +/** > + * Message data length > + * > + * Return length of the message data. > + * > + * @param msg Message handle > + * > + * @return Message length > + */ > +uint32_t odp_ipc_length(const odp_ipc_msg_t msg); > Should these two be combined to eliminate the need to call both? Wouldn't one expect to need both address and length in most instances? Also, does this imply that all odp_ipc_msg_t objects are contiguously addressable? That requirement might be problematic for some implementations. We can certainly allow the application to define a minimum msg segment size (as part of the pool creation), but if "large" objects can be passed via the IPC mechanism (e.g., packets) then it would seem that the API should be defined to support segmented addressability. This is especially true if the endpoints are defined in different pools (as one would expect) that have independently-configurable segmentation. > + > +/** > + * Set message length > + * > + * Set length of the message data. > + * > + * @param msg Message handle > + * @param len New length > + * > + * @retval 0 on success > + * @retval <0 on error > + */ > +int odp_ipc_reset(const odp_ipc_msg_t msg, uint32_t len); > + > +/** > + * Allocate message > + * > + * Allocate a message of a specific size. > + * > + * @param pool Message pool to allocate message from > + * @param len Length of the allocated message > + * > + * @return IPC message handle on success > + * @retval ODP_IPC_MSG_INVALID on failure and errno set > + */ > +odp_ipc_msg_t odp_ipc_alloc(odp_pool_t pool, uint32_t len); > + > +/** > + * Free message > + * > + * Free message back to the message pool it was allocated from. > + * > + * @param msg Handle of message to free > + */ > +void odp_ipc_free(odp_ipc_msg_t msg); > + > +/** > + * Get message handle from event > + * > + * Converts an ODP_EVENT_MESSAGE type event to a message. > + * > + * @param ev Event handle > + * > + * @return Message handle > + * > + * @see odp_event_type() > + */ > +odp_ipc_msg_t odp_message_from_event(odp_event_t ev); > + > +/** > + * Convert message handle to event > + * > + * @param msg Message handle > + * > + * @return Event handle > + */ > +odp_event_t odp_message_to_event(odp_ipc_msg_t msg); > + > +/** > + * Get printable value for an odp_ipc_t > + * > + * @param ipc IPC handle to be printed > + * @return uint64_t value that can be used to print/display this > + * handle > + * > + * @note This routine is intended to be used for diagnostic purposes > + * to enable applications to generate a printable value that represents > + * an odp_ipc_t handle. > + */ > +uint64_t odp_ipc_to_u64(odp_ipc_t ipc); > + > +/** > + * Get printable value for an odp_ipc_msg_t > + * > + * @param msg Message handle to be printed > + * @return uint64_t value that can be used to print/display this > + * handle > + * > + * @note This routine is intended to be used for diagnostic purposes > + * to enable applications to generate a printable value that represents > + * an odp_ipc_msg_t handle. > + */ > +uint64_t odp_ipc_msg_to_u64(odp_ipc_msg_t msg); > + > +/** > + * @} > + */ > + > +#ifdef __cplusplus > +} > +#endif > + > +#endif > -- > 1.9.1 > > _______________________________________________ > lng-odp mailing list > [email protected] > https://lists.linaro.org/mailman/listinfo/lng-odp >
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