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Change erasure ratio to 0.25 and increase data shreds to 16 (#5931)

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* Change erasure ratio to 0.25 and increase data shreds to 16

* Fix case where no coding shreds are requested
This commit is contained in:
Sagar Dhawan
2019-09-17 11:59:14 -07:00
committed by GitHub
parent 9e680112e7
commit 14cb6353c0
2 changed files with 14 additions and 6 deletions
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7
core/src/shred.rs
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@@ -168,7 +168,9 @@ pub enum Shred {
/// This limit comes from reed solomon library, but unfortunately they don't have
/// a public constant defined for it.
const MAX_DATA_SHREDS_PER_FEC_BLOCK: u32 = 4;
const MAX_DATA_SHREDS_PER_FEC_BLOCK: u32 = 16;
/// Based on rse benchmarks, the optimal erasure config uses 16 data shreds and 4 coding shreds
pub const RECOMMENDED_FEC_RATE: f32 = 0.25;
const LAST_SHRED_IN_SLOT: u8 = 0b0000_0001;
const DATA_COMPLETE_SHRED: u8 = 0b0000_0010;
@@ -624,7 +626,8 @@ impl Shredder {
fn generate_coding_shreds(&mut self) {
if self.fec_rate != 0.0 {
let num_data = (self.index - self.fec_set_index) as usize;
let num_coding = (self.fec_rate * num_data as f32) as usize;
// always generate at least 1 coding shred even if the fec_rate doesn't allow it
let num_coding = 1.max((self.fec_rate * num_data as f32) as usize);
let session =
Session::new(num_data, num_coding).expect("Failed to create erasure session");
let start_index = self.index - num_data as u32;