Solana: How can a Rust program get access to the `syscall_base_cost` value?

Getting access to compute budget values ​​in Rust

When creating a Solana program, one of the critical elements is the compute budget, which defines the cost of executing instructions. In this article, we will explore how to access specific values ​​within the compute budget using Rust.

SystemCallBaseCost Value

The syscall_base_cost value represents the base cost of a system call in Solana. This value determines how much gas is needed to execute a system call. Although it is not directly accessible from outside the program, it can be obtained programmatically using the Solana SDK.

Here is a sample code snippet that sets a default compute budget with some sample values:

use solana_program::{
account_info::{next_account_info, AccountInfo},
entrypoint::ProgramResult,
exec_info::{self, ProgramId, EntrypointEntry, EntrypointError},
program_error::Printing Error,
pubkey::pubkey,
};
use std::collections::HashMap;
// Define the compute budget
const COMPUTE_BUDGET: &mut HashMap, u64> = {
let mut budget = HashMap::new();
budget.insert(next_account_info().pubkey, 100_000); // 100k gas for execution
budget.insert(next_account_info().pubkey, 50_000); // 50k gas for creating a transaction
};

Accessing the computation budget values

To access specific values ​​within the computation budget, you can use the get method provided by the HashMap implementation. For example:

fn main() -> Program Result {
// Get the calculated cost of executing a system call
let syscall_base_cost = budget.get(&next_account_info().pubkey)?;
println!("System call base cost: {}", syscall_base_cost);
// Get the total processing cost for creating an account
leave account_create_cost = budget.get(&next_account_info().account_pubkey)?;
println!("Account creation cost: {}", account_create_cost);
// Get the minimum compute cost required for a system call
let min_syscall_cost = budget.get(&next_account_info().pubkey)?.min(?;
println!("Minimum system call cost: {}", min_syscall_cost);
}

Example Use Cases

Here’s an example of how you can use these values ​​to optimize your program:

• When executing a system call, ensure that syscall_base_cost is greater than or equal to the minimum compute cost required for that statement.

• If creating a transaction requires more gas than is available in your compute budget, consider using a separate account with higher gas limits.

Best Practices

To ensure safe and efficient use of compute budget values:

• Keep track of your remaining compute budget at regular intervals.

• Check syscall_base_cost before executing system calls. system to avoid exceeding the minimum required cost.

• Use separate accounts or contexts for sensitive computations that require more gas than is available in the compute budget.

By following these guidelines and using the Solana SDK, you can effectively manage compute budget values ​​within your Rust program.