The GOMAXPROCS
environment variable in Go is used to set the maximum number of CPUs that the Go runtime can utilize simultaneously to execute Go routines. This variable essentially controls the degree of parallelism that the Go runtime can employ.
Here's a breakdown of its purpose and usage:
Purpose:
- Control the maximum number of CPUs that Go can utilize concurrently for executing Go routines.
Usage:
- Set
GOMAXPROCS
to a positive integer value to specify the maximum number of CPUs that the Go runtime can use. - If
GOMAXPROCS
is not set explicitly, Go runtime will use the number of logical CPUs available on the machine.
When to Use:
- Adjust
GOMAXPROCS
to optimize performance for CPU-bound applications by utilizing multiple CPU cores efficiently. - Useful for controlling the level of parallelism in concurrent programs.
Example:
# Set GOMAXPROCS to utilize 4 CPU cores
GOMAXPROCS=4 go run main.go
In the example above, GOMAXPROCS
is set to 4, instructing the Go runtime to utilize up to 4 CPU cores for executing Go routines concurrently.
This environment variable is particularly beneficial for optimizing performance in multi-threaded Go applications where parallelism can significantly enhance throughput and responsiveness. However, it's essential to balance the value of GOMAXPROCS
based on the specific workload and characteristics of the underlying hardware to achieve optimal performance.