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BufWriter: use #[cold] and less aggressive #[inline] hints

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This commit is contained in:
Tyson Nottingham 2021-01-04 17:53:23 -08:00
parent 72aecbfd01
commit 85bc88df5f
1 changed files with 3 additions and 1 deletions
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4
library/std/src/io/buffered/bufwriter.rs
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@ -351,6 +351,7 @@ impl<W: Write> BufWriter<W> {
// If this function ends up being called frequently relative to `write`, // If this function ends up being called frequently relative to `write`,
// it's likely a sign that the client is using an improperly sized buffer // it's likely a sign that the client is using an improperly sized buffer
// or their write patterns are somewhat pathological. // or their write patterns are somewhat pathological.
#[cold]
#[inline(never)] #[inline(never)]
fn write_cold(&mut self, buf: &[u8]) -> io::Result<usize> { fn write_cold(&mut self, buf: &[u8]) -> io::Result<usize> {
if buf.len() > self.spare_capacity() { if buf.len() > self.spare_capacity() {
@ -385,6 +386,7 @@ impl<W: Write> BufWriter<W> {
// If this function ends up being called frequently relative to `write_all`, // If this function ends up being called frequently relative to `write_all`,
// it's likely a sign that the client is using an improperly sized buffer // it's likely a sign that the client is using an improperly sized buffer
// or their write patterns are somewhat pathological. // or their write patterns are somewhat pathological.
#[cold]
#[inline(never)] #[inline(never)]
fn write_all_cold(&mut self, buf: &[u8]) -> io::Result<()> { fn write_all_cold(&mut self, buf: &[u8]) -> io::Result<()> {
// Normally, `write_all` just calls `write` in a loop. We can do better // Normally, `write_all` just calls `write` in a loop. We can do better
@ -421,7 +423,7 @@ impl<W: Write> BufWriter<W> {
// SAFETY: Requires `buf.len() <= self.buf.capacity() - self.buf.len()`, // SAFETY: Requires `buf.len() <= self.buf.capacity() - self.buf.len()`,
// i.e., that input buffer length is less than or equal to spare capacity. // i.e., that input buffer length is less than or equal to spare capacity.
#[inline(always)] #[inline]
unsafe fn write_to_buffer_unchecked(&mut self, buf: &[u8]) { unsafe fn write_to_buffer_unchecked(&mut self, buf: &[u8]) {
debug_assert!(buf.len() <= self.spare_capacity()); debug_assert!(buf.len() <= self.spare_capacity());
let old_len = self.buf.len(); let old_len = self.buf.len();