ext: Benchmark tests.

Added benchmark tests which emulate memfs benchmarks.

Stat benchmarks
BenchmarkVFS2Ext4fsStat/1-12      	10000000	       145 ns/op
BenchmarkVFS2Ext4fsStat/2-12      	10000000	       170 ns/op
BenchmarkVFS2Ext4fsStat/3-12      	10000000	       202 ns/op
BenchmarkVFS2Ext4fsStat/8-12      	 3000000	       374 ns/op
BenchmarkVFS2Ext4fsStat/64-12     	  500000	      2159 ns/op
BenchmarkVFS2Ext4fsStat/100-12    	  300000	      3459 ns/op

BenchmarkVFS1TmpfsStat/1-12       	 5000000	       348 ns/op
BenchmarkVFS1TmpfsStat/2-12       	 3000000	       487 ns/op
BenchmarkVFS1TmpfsStat/3-12       	 2000000	       655 ns/op
BenchmarkVFS1TmpfsStat/8-12       	 1000000	      1365 ns/op
BenchmarkVFS1TmpfsStat/64-12      	  200000	      9565 ns/op
BenchmarkVFS1TmpfsStat/100-12     	  100000	     15158 ns/op

BenchmarkVFS2MemfsStat/1-12       	10000000	       133 ns/op
BenchmarkVFS2MemfsStat/2-12       	10000000	       155 ns/op
BenchmarkVFS2MemfsStat/3-12       	10000000	       182 ns/op
BenchmarkVFS2MemfsStat/8-12       	 5000000	       310 ns/op
BenchmarkVFS2MemfsStat/64-12      	 1000000	      1659 ns/op
BenchmarkVFS2MemfsStat/100-12     	  500000	      2787 ns/op

Mount Stat benchmarks
BenchmarkVFS2ExtfsMountStat/1-12  	 5000000	       245 ns/op
BenchmarkVFS2ExtfsMountStat/2-12  	 5000000	       266 ns/op
BenchmarkVFS2ExtfsMountStat/3-12  	 5000000	       304 ns/op
BenchmarkVFS2ExtfsMountStat/8-12  	 3000000	       456 ns/op
BenchmarkVFS2ExtfsMountStat/64-12 	  500000	      2308 ns/op
BenchmarkVFS2ExtfsMountStat/100-12   300000	      3482 ns/op

BenchmarkVFS1TmpfsMountStat/1-12  	 3000000	       488 ns/op
BenchmarkVFS1TmpfsMountStat/2-12  	 2000000	       658 ns/op
BenchmarkVFS1TmpfsMountStat/3-12  	 2000000	       806 ns/op
BenchmarkVFS1TmpfsMountStat/8-12  	 1000000	      1514 ns/op
BenchmarkVFS1TmpfsMountStat/64-12 	  100000	     10037 ns/op
BenchmarkVFS1TmpfsMountStat/100-12        100000	     15280 ns/op

BenchmarkVFS2MemfsMountStat/1-12           	10000000	       212 ns/op
BenchmarkVFS2MemfsMountStat/2-12           	 5000000	       232 ns/op
BenchmarkVFS2MemfsMountStat/3-12           	 5000000	       264 ns/op
BenchmarkVFS2MemfsMountStat/8-12           	 3000000	       390 ns/op
BenchmarkVFS2MemfsMountStat/64-12          	 1000000	      1813 ns/op
BenchmarkVFS2MemfsMountStat/100-12         	  500000	      2812 ns/op

PiperOrigin-RevId: 262477158

1 files changed, 72 insertions, 0 deletions

diff --git a/pkg/sentry/fs/ext/benchmark/make_deep_ext4.sh b/pkg/sentry/fs/ext/benchmark/make_deep_ext4.sh
new file mode 100755
index 000000000..d0910da1f
--- /dev/null
+++ b/pkg/sentry/fs/ext/benchmark/make_deep_ext4.sh
@@ -0,0 +1,72 @@
+#!/bin/bash
+
+# Copyright 2019 The gVisor Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# This script creates an ext4 image with $1 depth of directories and a file in
+# the inner most directory. The created file is at path /1/2/.../depth/file.txt.
+# The ext4 image is written to $2. The image is temporarily mounted at
+# /tmp/mountpoint. This script must be run with sudo privileges.
+
+# Usage:
+# sudo bash make_deep_ext4.sh {depth} {output path}
+
+# Check positional arguments.
+if [ "$#" -ne 2 ]; then
+    echo "Usage: sudo bash make_deep_ext4.sh {depth} {output path}"
+    exit 1
+fi
+
+# Make sure depth is a non-negative number.
+if ! [[ "$1" =~ ^[0-9]+$ ]]; then
+        echo "Depth must be a non-negative number."
+        exit 1
+fi
+
+# Create a 1 MB filesystem image at the requested output path.
+rm -f $2
+fallocate -l 1M $2
+if [ $? -ne 0 ]; then
+    echo "fallocate failed"
+    exit $?
+fi
+
+# Convert that blank into an ext4 image.
+mkfs.ext4 -j $2
+if [ $? -ne 0 ]; then
+    echo "mkfs.ext4 failed"
+    exit $?
+fi
+
+# Mount the image.
+MOUNTPOINT=/tmp/mountpoint
+mkdir -p $MOUNTPOINT
+mount -o loop $2 $MOUNTPOINT
+if [ $? -ne 0 ]; then
+    echo "mount failed"
+    exit $?
+fi
+
+# Create nested directories and the file.
+if [ "$1" -eq 0 ]; then
+   FILEPATH=$MOUNTPOINT/file.txt
+else
+   FILEPATH=$MOUNTPOINT/$(seq -s '/' 1 $1)/file.txt
+fi
+mkdir -p $(dirname $FILEPATH) || exit
+touch $FILEPATH
+
+# Clean up.
+umount $MOUNTPOINT
+rm -rf $MOUNTPOINT