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This Concept Map, created with IHMC CmapTools, has information related to: Communication, -making invocations concurrently -asynchronous invocations -persisten asysnchronous invocations includes -invocation costs -invocation over the network -memory sharing -choice of protocol -invocation within a computer -discussion of LRPC, latency: Null Invocation costs are the delays required to set up communications and the non-goal performing overhead of invocations. These fixed overhead costs measure the latency of the connection. Substantial efforts go into minimizing and reducing latency costs in distributed applications. contains invocation: The invocation of a local process takes place within local memory and may involve a few tens of instruction cycles. Invocation of a remote process involves network activities and possibly access to files, and may require billions of instruction cycles in processors running at speeds measured in gigahertz. These invocation activities are external to the desired processing activities and increase costs without adding value., invocation overhead: In a typical employment situation, a worker might be expected to complete a number of tasks each day that contribute toward the goals of the employer. To accomplish those tasks, the worker might also have to accomplish tasks, such as commuting to work, that do not contribute directly to the employer’s goals. A process also has tasks that are within the scope of the process and tasks that do not contribute directly to goals. Process invocation can be compared to commuting as an overhead expense. has -making invocations concurrently -asynchronous invocations -persisten asysnchronous invocations, invocation overhead: In a typical employment situation, a worker might be expected to complete a number of tasks each day that contribute toward the goals of the employer. To accomplish those tasks, the worker might also have to accomplish tasks, such as commuting to work, that do not contribute directly to the employer’s goals. A process also has tasks that are within the scope of the process and tasks that do not contribute directly to goals. Process invocation can be compared to commuting as an overhead expense. has asynchronous operation, latency: Null Invocation costs are the delays required to set up communications and the non-goal performing overhead of invocations. These fixed overhead costs measure the latency of the connection. Substantial efforts go into minimizing and reducing latency costs in distributed applications. contains concurrent invocation: Another approach to reducing communication overhead is to reduce the number of messages sent to establish the connection and to continue processing while communicating instead of suspending threads until a message is received. Serialized and concurrent invocations are compared on the next slide., latency: Null Invocation costs are the delays required to set up communications and the non-goal performing overhead of invocations. These fixed overhead costs measure the latency of the connection. Substantial efforts go into minimizing and reducing latency costs in distributed applications. contains lightweight RPC: One way to reduce the overhead of a remote invocation is to share some of the costs. While process invocation is expensive, some activities can be done once and then reused, while others must be done for each communication. Lightweight RPC attempts to minimize overhead by sharing process activities within parent processes that are pre-established. Overhead costs can be reduced by as much as two-thirds., latency: Null Invocation costs are the delays required to set up communications and the non-goal performing overhead of invocations. These fixed overhead costs measure the latency of the connection. Substantial efforts go into minimizing and reducing latency costs in distributed applications. contains invocation costs as a percentage of throughput: As more goal work is accomplished for a fixed amount of overhead, the overhead is less of a concern as a percentage of total costs. With very small data sizes, most of the system time may be spent in overhead activities. With large data transfers, the overhead costs may be negligible as a percentage of total costs., latency: Null Invocation costs are the delays required to set up communications and the non-goal performing overhead of invocations. These fixed overhead costs measure the latency of the connection. Substantial efforts go into minimizing and reducing latency costs in distributed applications. contains invocation overhead: In a typical employment situation, a worker might be expected to complete a number of tasks each day that contribute toward the goals of the employer. To accomplish those tasks, the worker might also have to accomplish tasks, such as commuting to work, that do not contribute directly to the employer’s goals. A process also has tasks that are within the scope of the process and tasks that do not contribute directly to goals. Process invocation can be compared to commuting as an overhead expense.