When testing an embedded flash file system for performance, it is important to consider data beyond just reads and writes.
Faster Mount Times
Because Reliance Nitro always maintains a "known good state," it has a mount time advantage particularly after power loss. In situations where there is random I/O penalty, such as in Hard Disk Drives and e•MMC, this advantage is magnified. Journaling file systems such as ext3 and ext4 will need to perform random reads to build the journal. Since Reliance Nitro always keeps the disk in a known good state, there is no need to run integrity checks during the file system boot, even after a disorderly shutdown.
Faster File Operations Deliver Superior Responsiveness
The tree-based architecture of the Reliance Nitro core results in faster access to file metadata, user file allocated blocks and free blocks. This results in a binary search for files and their data blocks, which means superior throughput when handling many small files.
Reliance Nitro demonstrates superior file system metadata handling. When reading and writing smaller files, this file system overhead is far more important than the raw throughput available. In the test below, run on a i.MX6 Sabre SD embedded board, using a PNY 4GB SD card for storage. Reliance Nitro created 1000 files in 24 seconds, compared to almost five minutes for the native filesystem solution.
In Linux, Reliance Nitro is fully factored into the kernel block cache mechanism. For non-Linux RTOS solutions, Datalight provides a fully configurable block device cache, allowing higher performance in some use cases. The chart below shows the impact of this cache on VxWorks read and write operations.
The write performance in the charts above was measured with a cache – the Reliance Nitro cache for Datalight, the DosFS cache for VxWorks. The media used in this test has a maximum performance of 5.1 mb/sec sequential write and a random write speed of at most 96 kb/sec. As you can see, the sequential read and write performance for Datalight is considerably better than DosFS, and while Reliance Nitro has excellent random write performance, it can be improved even further with cache support.