Btrfs Battles EXT4 With The Linux 2.6.33 Kernel
Written by Michael Larabel in Software on 21 January 2010. Page 5 of 5. 29 Comments

The Phoronix Test Suite is also capable of monitoring the CPU usage, Iowait, and other system sensors and metrics while the testing is taking place. To look at the impact particularly when using zlib compression with Btrfs due to the additional CPU overhead we used the Phoronix Test Suite's system monitor module as we ran Dbench with 128 clients, IOzone 2GB reads, and then PostMark. Below are the Phoronix Test Suite's recordings of the CPU usage during these three benchmarks.

To no surprise Btrfs with compression enabled had the highest CPU usage with the dual-core Intel Atom 330 being 13% more utilized than with Btrfs and no zlib compression. To some surprise though, when comparing EXT4 and Btrfs, Btrfs had a slightly lower CPU utilization rate than the evolutionary EXT4.

On average Btrfs with transparent compression enabled led to the lowest iowait and it also peaked much lower than EXT4 and Btrfs.

With these new file-system benchmarks against the latest Linux 2.6.33 kernel, Btrfs did remarkably well and continued to have more wins than even with the recent Linux 2.6.32 kernel. Btrfs pulled its wins with Dbench, FS-Mark, and the Threaded I/O Tester. Btrfs lost to EXT4 with PostgreSQL, Iozone write performance, Iozone read performance too except when compression was enabled, and PostMark except when using the file-system's transparent compression. Using the transparent zlib compression was of advantage in many of the benchmarks, but with only modestly taxing the CPU (+13% for an Intel Atom). We will be looking closer at the Btrfs zlib compression performance in a forthcoming article when we look in detail at what it has to offer for netbook users. There is also the Btrfs SSD mode for greater tuning.

About The Author
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Michael Larabel is the principal author of Phoronix.com and founded the web-site in 2004 with a focus on enriching the Linux hardware experience and being the largest web-site devoted to Linux hardware reviews, particularly for products relevant to Linux gamers and enthusiasts but also commonly reviewing servers/workstations and embedded Linux devices. Michael has written more than 10,000 articles covering the state of Linux hardware support, Linux performance, graphics hardware drivers, and other topics. Michael is also the lead developer of the Phoronix Test Suite, Phoromatic, and OpenBenchmarking.org automated testing software. He can be followed via Twitter or contacted via MichaelLarabel.com.

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