Merge pull request #2011 from subspace/farmer-disk-io-refactoring

Farmer disk I/O refactoring

crates/subspace-farmer-components/Cargo.toml

@@ -43,7 +43,6 @@ tracing = "0.1.37"
 [dev-dependencies]
 criterion = "0.5.1"
 futures = "0.3.28"
-memmap2 = "0.7.1"
 subspace-archiving = { version = "0.1.0", path = "../subspace-archiving" }
 subspace-proof-of-space = { version = "0.1.0", path = "../subspace-proof-of-space", features = ["chia"] }
 

crates/subspace-farmer-components/benches/auditing.rs

@@ -1,6 +1,5 @@
 use criterion::{black_box, criterion_group, criterion_main, Criterion, Throughput};
 use futures::executor::block_on;
-use memmap2::Mmap;
 use rand::prelude::*;
 use std::fs::OpenOptions;
 use std::io::Write;
@@ -21,7 +20,7 @@ use subspace_farmer_components::plotting::{plot_sector, PieceGetterRetryPolicy,
 use subspace_farmer_components::sector::{
     sector_size, SectorContentsMap, SectorMetadata, SectorMetadataChecksummed,
 };
-use subspace_farmer_components::FarmerProtocolInfo;
+use subspace_farmer_components::{FarmerProtocolInfo, ReadAt};
 use subspace_proof_of_space::chia::ChiaTable;
 use subspace_proof_of_space::Table;
 
@@ -183,29 +182,19 @@ pub fn criterion_benchmark(c: &mut Criterion) {
                 .unwrap();
         }
 
-        let plot_mmap = unsafe { Mmap::map(&plot_file).unwrap() };
-
-        #[cfg(unix)]
-        {
-            plot_mmap.advise(memmap2::Advice::Random).unwrap();
-        }
-
         group.throughput(Throughput::Elements(sectors_count));
-        group.bench_function("disk", move |b| {
+        group.bench_function("disk", |b| {
             b.iter_custom(|iters| {
                 let start = Instant::now();
                 for _i in 0..iters {
-                    for (sector_index, sector) in plot_mmap
-                        .chunks_exact(sector_size)
-                        .enumerate()
-                        .map(|(sector_index, sector)| (sector_index as SectorIndex, sector))
-                    {
+                    for sector_index in 0..sectors_count as usize {
+                        let sector = plot_file.offset(sector_index * sector_size);
                         audit_sector(
                             black_box(&public_key),
-                            black_box(sector_index),
+                            black_box(sector_index as SectorIndex),
                             black_box(&global_challenge),
                             black_box(solution_range),
-                            black_box(sector),
+                            black_box(&sector),
                             black_box(&plotted_sector.sector_metadata),
                         );
                     }

crates/subspace-farmer-components/benches/proving.rs

@@ -1,6 +1,5 @@
 use criterion::{black_box, criterion_group, criterion_main, Criterion, Throughput};
 use futures::executor::block_on;
-use memmap2::Mmap;
 use rand::prelude::*;
 use schnorrkel::Keypair;
 use std::fs::OpenOptions;
@@ -21,7 +20,7 @@ use subspace_farmer_components::plotting::{plot_sector, PieceGetterRetryPolicy,
 use subspace_farmer_components::sector::{
     sector_size, SectorContentsMap, SectorMetadata, SectorMetadataChecksummed,
 };
-use subspace_farmer_components::FarmerProtocolInfo;
+use subspace_farmer_components::{FarmerProtocolInfo, ReadAt};
 use subspace_proof_of_space::chia::ChiaTable;
 use subspace_proof_of_space::Table;
 
@@ -234,15 +233,12 @@ pub fn criterion_benchmark(c: &mut Criterion) {
                 .unwrap();
         }
 
-        let plot_mmap = unsafe { Mmap::map(&plot_file).unwrap() };
-
-        #[cfg(unix)]
-        {
-            plot_mmap.advise(memmap2::Advice::Random).unwrap();
-        }
+        let sectors = (0..sectors_count as usize)
+            .map(|sector_offset| plot_file.offset(sector_offset * sector_size))
+            .collect::<Vec<_>>();
 
-        let solution_candidates = plot_mmap
-            .chunks_exact(sector_size)
+        let solution_candidates = sectors
+            .iter()
             .map(|sector| {
                 audit_sector(
                     &public_key,

crates/subspace-farmer-components/benches/reading.rs

@@ -1,6 +1,5 @@
 use criterion::{black_box, criterion_group, criterion_main, Criterion, Throughput};
 use futures::executor::block_on;
-use memmap2::Mmap;
 use rand::prelude::*;
 use std::fs::OpenOptions;
 use std::io::Write;
@@ -20,7 +19,7 @@ use subspace_farmer_components::reading::read_piece;
 use subspace_farmer_components::sector::{
     sector_size, SectorContentsMap, SectorMetadata, SectorMetadataChecksummed,
 };
-use subspace_farmer_components::FarmerProtocolInfo;
+use subspace_farmer_components::{FarmerProtocolInfo, ReadAt};
 use subspace_proof_of_space::chia::ChiaTable;
 use subspace_proof_of_space::Table;
 
@@ -148,7 +147,7 @@ pub fn criterion_benchmark(c: &mut Criterion) {
     group.throughput(Throughput::Elements(1));
     group.bench_function("piece/memory", |b| {
         b.iter(|| {
-            read_piece::<PosTable>(
+            read_piece::<PosTable, _>(
                 black_box(piece_offset),
                 black_box(&plotted_sector.sector_id),
                 black_box(&plotted_sector.sector_metadata),
@@ -183,24 +182,18 @@ pub fn criterion_benchmark(c: &mut Criterion) {
                 .unwrap();
         }
 
-        let plot_mmap = unsafe { Mmap::map(&plot_file).unwrap() };
-
-        #[cfg(unix)]
-        {
-            plot_mmap.advise(memmap2::Advice::Random).unwrap();
-        }
-
         group.throughput(Throughput::Elements(sectors_count));
-        group.bench_function("piece/disk", move |b| {
+        group.bench_function("piece/disk", |b| {
             b.iter_custom(|iters| {
                 let start = Instant::now();
                 for _i in 0..iters {
-                    for sector in plot_mmap.chunks_exact(sector_size) {
-                        read_piece::<PosTable>(
+                    for sector_index in 0..sectors_count as usize {
+                        let sector = plot_file.offset(sector_index * sector_size);
+                        read_piece::<PosTable, _>(
                             black_box(piece_offset),
                             black_box(&plotted_sector.sector_id),
                             black_box(&plotted_sector.sector_metadata),
-                            black_box(sector),
+                            black_box(&sector),
                             black_box(&erasure_coding),
                             black_box(&mut table_generator),
                         )

crates/subspace-farmer-components/src/auditing.rs

@@ -1,10 +1,12 @@
 use crate::proving::SolutionCandidates;
 use crate::sector::{SectorContentsMap, SectorMetadataChecksummed};
+use crate::ReadAt;
 use std::collections::VecDeque;
 use std::mem;
 use subspace_core_primitives::crypto::Scalar;
 use subspace_core_primitives::{Blake2b256Hash, PublicKey, SectorId, SectorIndex, SolutionRange};
 use subspace_verification::is_within_solution_range;
+use tracing::warn;
 
 #[derive(Debug, Clone)]
 pub(crate) struct ChunkCandidate {
@@ -17,20 +19,23 @@ pub(crate) struct ChunkCandidate {
 /// Audit a single sector and generate a stream of solutions, where `sector` must be positioned
 /// correctly at the beginning of the sector (seek to desired offset before calling this function
 /// and seek back afterwards if necessary).
-pub fn audit_sector<'a>(
+pub fn audit_sector<'a, Sector>(
     public_key: &'a PublicKey,
     sector_index: SectorIndex,
     global_challenge: &Blake2b256Hash,
     solution_range: SolutionRange,
-    sector: &'a [u8],
+    sector: &'a Sector,
     sector_metadata: &'a SectorMetadataChecksummed,
-) -> Option<SolutionCandidates<'a>> {
+) -> Option<SolutionCandidates<'a, Sector>>
+where
+    Sector: ReadAt + ?Sized,
+{
     let sector_id = SectorId::new(public_key.hash(), sector_index);
 
     let sector_slot_challenge = sector_id.derive_sector_slot_challenge(global_challenge);
     let s_bucket_audit_index = sector_slot_challenge.s_bucket_audit_index();
-    let s_bucket_audit_size = Scalar::FULL_BYTES
-        * usize::from(sector_metadata.s_bucket_sizes[usize::from(s_bucket_audit_index)]);
+    let s_bucket_audit_size =
+        usize::from(sector_metadata.s_bucket_sizes[usize::from(s_bucket_audit_index)]);
     let s_bucket_audit_offset = Scalar::FULL_BYTES
         * sector_metadata
             .s_bucket_sizes
@@ -43,15 +48,19 @@ pub fn audit_sector<'a>(
     let sector_contents_map_size =
         SectorContentsMap::encoded_size(sector_metadata.pieces_in_sector);
 
-    // Read s-bucket
-    let s_bucket =
-        &sector[sector_contents_map_size + s_bucket_audit_offset..][..s_bucket_audit_size];
+    let s_bucket_audit_offset_in_sector = sector_contents_map_size + s_bucket_audit_offset;
 
     // Map all winning chunks
-    let winning_chunks = s_bucket
-        .array_chunks::<{ Scalar::FULL_BYTES }>()
-        .enumerate()
-        .filter_map(|(chunk_offset, chunk)| {
+    let winning_chunks = (0..s_bucket_audit_size)
+        .filter_map(|chunk_offset| {
+            let mut chunk = [0; Scalar::FULL_BYTES];
+            if let Err(error) = sector.read_at(
+                &mut chunk,
+                s_bucket_audit_offset_in_sector + chunk_offset * Scalar::FULL_BYTES,
+            ) {
+                warn!(%error, %sector_index, %chunk_offset, "Failed read chunk sector");
+                return None;
+            }
             // Check all audit chunks within chunk, there might be more than one winning
             let winning_audit_chunk_offsets = chunk
                 .array_chunks::<{ mem::size_of::<SolutionRange>() }>()

crates/subspace-farmer-components/src/lib.rs

@@ -22,10 +22,78 @@ pub mod reading;
 pub mod sector;
 mod segment_reconstruction;
 
+use crate::file_ext::FileExt;
 use serde::{Deserialize, Serialize};
 use static_assertions::const_assert;
+use std::fs::File;
+use std::io;
 use subspace_core_primitives::HistorySize;
 
+/// Trait for reading data at specific offset
+pub trait ReadAt: Send + Sync {
+    /// Get implementation of [`ReadAt`] that add specified offset to all attempted reads
+    fn offset(&self, offset: usize) -> ReadAtOffset<&Self>
+    where
+        Self: Sized,
+    {
+        ReadAtOffset {
+            inner: self,
+            offset,
+        }
+    }
+
+    /// Fill the buffer by reading bytes at a specific offset
+    fn read_at(&self, buf: &mut [u8], offset: usize) -> io::Result<()>;
+}
+
+impl ReadAt for [u8] {
+    fn read_at(&self, buf: &mut [u8], offset: usize) -> io::Result<()> {
+        if buf.len() + offset > self.len() {
+            return Err(io::Error::new(
+                io::ErrorKind::InvalidInput,
+                "Buffer length with offset exceeds own length",
+            ));
+        }
+
+        buf.copy_from_slice(&self[offset..][..buf.len()]);
+
+        Ok(())
+    }
+}
+
+impl ReadAt for Vec<u8> {
+    fn read_at(&self, buf: &mut [u8], offset: usize) -> io::Result<()> {
+        self.as_slice().read_at(buf, offset)
+    }
+}
+
+impl ReadAt for File {
+    fn read_at(&self, buf: &mut [u8], offset: usize) -> io::Result<()> {
+        self.read_exact_at(buf, offset as u64)
+    }
+}
+
+impl ReadAt for &File {
+    fn read_at(&self, buf: &mut [u8], offset: usize) -> io::Result<()> {
+        self.read_exact_at(buf, offset as u64)
+    }
+}
+
+/// Reader with fixed offset added to all attempted reads
+pub struct ReadAtOffset<T> {
+    inner: T,
+    offset: usize,
+}
+
+impl<T> ReadAt for ReadAtOffset<T>
+where
+    T: ReadAt,
+{
+    fn read_at(&self, buf: &mut [u8], offset: usize) -> io::Result<()> {
+        self.inner.read_at(buf, offset + self.offset)
+    }
+}
+
 // Refuse to compile on non-64-bit platforms, offsets may fail on those when converting from u64 to
 // usize depending on chain parameters
 const_assert!(std::mem::size_of::<usize>() >= std::mem::size_of::<u64>());