US 5,694,333 A · System and method for performing more efficient window context switching in an instrumentation system

Abstract

A system and method for performing more efficient hardware context switches in a computer-controlled instrumentation system including a computer system which controls a plurality of instruments. The instrumentation system includes a direct memory access transfer device which performs various data transfers between the computer system and the various instruments. The system also includes a plurality of processes executing in the computer system which operates through a common window to map cycles onto the instrumentation bus to the various instruments. Each process or thread executing on the CPU requires a specific context, and the DMA transfer device automatically configures itself to different contexts in parallel with operating system context changes. Each process includes corresponding context information stored in memory. When the operating system is invoked to switch in a new process on the CPU, the operating system writes the address of the context information to the DMA transfer device. The DMA transfer device reads the context from memory and automatically configures itself in parallel with context changes performed by the operating system.

Claims18

Dependent claims

A method for performing context switches in an instrumentation system comprising a CPU, a memory coupled to the CPU, a plurality of instruments, and a direct memory access transfer device coupled to the memory and the plurality of instruments, wherein a plurality of processes execute on the CPU to perform operations on the plurality of instruments, the method comprising the steps of:

storing a first context in the memory at a first address;
providing said first address of said first context to the direct memory access transfer device, wherein said first context corresponds to a first process and wherein said first process requires the direct memory access transfer device to have said first context when said first process is executing on the CPU;
the direct memory access transfer device receiving said first address;
the direct memory access transfer device reading said first context from the memory using said first address;
the direct memory access transfer device configuring itself according to said first context after said step of reading said first context from the memory;
and
said first process beginning execution on the CPU after said step of the direct memory access transfer device configuring itself according to said first context.

4 more elements

An instrumentation system which performs more efficient context switching operations, comprising:

an instrumentation bus;
a plurality of instruments coupled to said instrumentation bus which perform desired tests and measurements,
a CPU which executes a plurality of processes for communicating with said plurality of instruments, wherein said CPU generates cycles which propagate to said instrumentation bus to communicate with said instruments in response to respective processes executing on said CPU;
a memory coupled to said CPU which stores a plurality of context data corresponding to said plurality of processes;
a direct memory access transfer device coupled to said CPU, said memory, said instrumentation bus, and said plurality of instruments;
wherein when a new process is to be switched in for execution on said CPU, said CPU notifies said direct memory access transfer device of said new process;
wherein the direct memory access transfer device includes context switching logic which reads one of said plurality of contexts from said memory corresponding to said new process and configures the direct memory access transfer device according to said one of said plurality of contexts corresponding to said new process in response to said CPU notifying said direct memory access transfer device of said new process.

4 more elements

Dependencies are inferred from the claim text.

System and method for performing more efficient window context switching in an instrumentation system

Life of this patent

System and method for performing more efficient window context switching in an instrumentation system

Life of this patent

Abstract

Claims18