[io-cache] New volume options for read sizes

Summary:
Two new volume options that control reads.

performance.io-cache.read-size
- Tells gluster how much it should try to read on each posix_readv call

performance.io-cache.min-cached-read-size
- Tells gluster the smallest files it should start caching, anything smaller is not cached

This is a port of D4844662 to 3.8

Change-Id: I5ba891906f97e514e7365cc34374619379434766
Reviewed-on: https://review.gluster.org/18235
Reviewed-by: Shreyas Siravara <sshreyas@fb.com>
CentOS-regression: Gluster Build System <jenkins@build.gluster.org>
Smoke: Gluster Build System <jenkins@build.gluster.org>

1 files changed, 65 insertions, 0 deletions

diff --git a/tests/basic/read-size.t b/tests/basic/read-size.t
new file mode 100644
index 00000000000..7161a5b8c24
--- /dev/null
+++ b/tests/basic/read-size.t
@@ -0,0 +1,65 @@
+#!/bin/bash
+
+. $(dirname $0)/../include.rc
+. $(dirname $0)/../volume.rc
+
+function clear_stats {
+        > /var/lib/glusterfs/stats/glusterfs_d_backends_${V0}*.dump
+}
+
+function got_expected_read_count {
+        expected_size=$1
+        expected_value=$2
+        grep -h aggr.read_${expected_size} /var/lib/glusterd/stats/glusterfsd__d_backends_${V0}*.dump \
+                | cut -d':' -f2 \
+                | grep "\"$expected_value\""
+        if [ $? == 0 ]; then
+          echo "Y";
+        else
+          echo "N";
+        fi
+}
+
+cleanup;
+
+TEST glusterd
+TEST pidof glusterd
+
+TEST $CLI volume create $V0 replica 3 $H0:$B0/${V0}{0,1,2}
+# These are needed for our tracking of write sizes 
+TEST $CLI volume set $V0 nfs.disable off
+TEST $CLI volume set $V0 diagnostics.latency-measurement on
+TEST $CLI volume set $V0 diagnostics.count-fop-hits on
+TEST $CLI volume set $V0 diagnostics.stats-dump-interval 2
+TEST $CLI volume set $V0 performance.io-cache on
+TEST $CLI volume set $V0 performance.nfs.io-cache on
+TEST $CLI volume set $V0 performance.io-cache.read-size 512KB
+EXPECT '512KB' volinfo_field $V0 'performance.io-cache.read-size'
+TEST $CLI volume set $V0 performance.io-cache.min-cached-read-size 32KB
+EXPECT '32KB' volinfo_field $V0 'performance.io-cache.min-cached-read-size'
+
+TEST $CLI volume start $V0
+
+sleep 2;
+
+TEST mount.nfs -overs=3,noacl,nolock,noatime $HOSTNAME:/$V0 $N0
+
+# First read of big file should not be cached
+TEST dd if=/dev/zero of=$N0/100mb_file bs=1M count=100 oflag=sync
+TEST cat $N0/100mb_file
+EXPECT_WITHIN 3 "Y" got_expected_read_count "512kb" 200
+
+# The number of reads should stay the same from the previous cat since they're cached
+TEST cat $N0/100mb_file
+EXPECT_WITHIN 3 "Y" got_expected_read_count "512kb" 200
+
+# Should not be cached
+TEST dd if=/dev/zero of=$N0/10kb_file bs=1K count=10 oflag=sync
+TEST cat $N0/10kb_file
+EXPECT_WITHIN 3 "Y" got_expected_read_count "8kb" 1
+
+# The reads should increment indicating they are not being cached
+TEST cat $N0/10kb_file
+EXPECT_WITHIN 3 "Y" got_expected_read_count "8kb" 2
+
+cleanup;