From 32c23136374d47aa7e4e54868aa2c10fd6aed476 Mon Sep 17 00:00:00 2001
From: Dave Lambley <davel@state51.co.uk>
Date: Wed, 13 Feb 2013 11:09:48 +0000
Subject: [PATCH] Tell the kernel we're doing sequential reads.

[ew: squashed Dave's change to make IO::AIO optional]

Signed-off-by: Eric Wong <normalperson@yhbt.net>
---
 lib/Mogstored/SideChannelClient.pm | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/lib/Mogstored/SideChannelClient.pm b/lib/Mogstored/SideChannelClient.pm
index f11f0e8..f3dbab3 100644
--- a/lib/Mogstored/SideChannelClient.pm
+++ b/lib/Mogstored/SideChannelClient.pm
@@ -12,6 +12,10 @@ use Digest;
 use POSIX qw(O_RDONLY);
 use Mogstored::TaskQueue;
 
+BEGIN {
+    eval { require IO::AIO; };
+}
+
 # TODO: interface to make this tunable
 my %digest_queues;
 
@@ -128,6 +132,9 @@ sub digest {
 
     Perlbal::AIO::aio_open("$path$uri", O_RDONLY, 0, sub {
         my $fh = shift;
+        eval {
+            IO::AIO::fadvise(fileno($fh), 0, 0, IO::AIO::FADV_SEQUENTIAL);
+        };
 
         if ($self->{closed}) {
             CORE::close($fh) if $fh;
-- 
2.11.4.GIT