Compute and Fees

Manage compute budget and fees for reliable landing. Results appear in the same fence: same-line // comments when short, multiline // blocks below the sample when not.

CU Limit

Set max compute units for the tx.

// ComputeBudgetInstruction::set_compute_unit_limit(300_000)

CU Price

Micro-lamports per CU for priority.

// ComputeBudgetInstruction::set_compute_unit_price(50_000)

Heap Frame

Request larger heap for heavy programs.

// ComputeBudgetInstruction::request_heap_frame(256 * 1024)

Log CU

sol_log_compute_units for debugging.

// sol_log_compute_units();

Fee Payer Lamports

Base fee + prioritization from fee payer.

// fee payer must have enough lamports

Default CU

Default CU limit if unset - set explicitly for heavy txs.

// prefer explicit set_compute_unit_limit

Simulate CU

Use simulation units_consumed as guide.

// sim.value.unitsConsumed

Many Signers Cost

Signature count affects base fee.

// minimize required signatures

ALT Saves

Lookup tables reduce message size/fees for many accounts.

// v0 + ALT

Writable Accounts

Writable account count impacts cost dimensions.

// mark readonly when possible

CPI CU

CPI consumes CU for callee too.

// budget for nested work

Priority Fee Market

Higher CU price competes for block space.

// sample getRecentPrioritizationFees

Loaded Accounts Data Size

Budget ix can request loaded accounts data size limit.

// set_loaded_accounts_data_size_limit

Fail Exhausted

Exceeding CU fails whole transaction.

// Computational budget exceeded

Local Test Unlimited

Local validators may use different defaults - still set CU in tests.

// set limit in test txs

Related

• Transactions and Instructions - budget ixs
• RPC Patterns - priority fee samples
• Program Errors and Logs - CU exceeded

Stack versions: This page was written for Agave 4.1.1, Solana CLI 3.0.10, Anchor 0.32.1, Rust 1.91.1, and @solana/kit 7.0.0.