From 0bb53636e4925ff98cc01dec8ac45299a0308832 Mon Sep 17 00:00:00 2001
From: Jeremy Soller <jackpot51@gmail.com>
Date: Tue, 19 Apr 2016 20:14:31 -0600
Subject: [PATCH] Faster read from disk if cache miss
---
scheme/cache/mod.rs | 22 ++++++++++++++++------
1 file changed, 16 insertions(+), 6 deletions(-)
diff --git a/scheme/cache/mod.rs b/scheme/cache/mod.rs
index faa1ad4..0709103 100644
--- a/scheme/cache/mod.rs
+++ b/scheme/cache/mod.rs
@@ -35,6 +35,7 @@ impl<T: Disk> Disk for Cache<T> {
// println!("Cache read at {}", block);
let mut read = 0;
+ let mut failed = false;
for i in 0..(buffer.len() + 511)/512 {
let block_i = block + i as u64;
@@ -42,18 +43,27 @@ impl<T: Disk> Disk for Cache<T> {
let buffer_j = cmp::min(buffer_i + 512, buffer.len());
let buffer_slice = &mut buffer[buffer_i .. buffer_j];
- //Just to fix the borrow checker in the else
- let mut failed = false;
if let Some(cache_buf) = self.cache.get_mut(&block_i) {
read += copy_memory(cache_buf, buffer_slice);
}else{
failed = true;
+ break;
}
+ }
+
+ if failed {
+ try!(self.inner.read_at(block, buffer));
+
+ read = 0;
+ for i in 0..(buffer.len() + 511)/512 {
+ let block_i = block + i as u64;
+
+ let buffer_i = i * 512;
+ let buffer_j = cmp::min(buffer_i + 512, buffer.len());
+ let buffer_slice = &buffer[buffer_i .. buffer_j];
- if failed {
let mut cache_buf = [0; 512];
- try!(self.inner.read_at(block_i, &mut cache_buf));
- read += copy_memory(&cache_buf, buffer_slice);
+ read += copy_memory(buffer_slice, &mut cache_buf);
self.cache.insert(block_i, cache_buf);
}
}
@@ -64,7 +74,7 @@ impl<T: Disk> Disk for Cache<T> {
fn write_at(&mut self, block: u64, buffer: &[u8]) -> Result<usize> {
// println!("Cache write at {}", block);
- try!(self.inner.write_at(block, &buffer));
+ try!(self.inner.write_at(block, buffer));
let mut written = 0;
for i in 0..(buffer.len() + 511)/512 {
--
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