The purpose of this test is to get an idea of AIO performance for a particular system/disk given a dynamic range of parameters.
The test is highly configurable in that the total number of AIO writes can be configured, as well as the size of each write and the total number of writes the test will perform.
The test results include averga throughput to disk, any reported AIO errors, and min, max, and avergae AIO write delays.
Future versions of this test should include simultaneous reads from the files being written to for more functional performance measuring.
aio_test usage:
Available options: -b, --batch size of maximum batch (default is no batching) -d, --directory Directory to write files -f, --fds number of file descriptors -h. --help print help -l, --length length of each batch write -p, --pool pool AIO's to specific fd's -r, --reads number of max outstanding reads -t, --total total number of writes -v, --verbose verbose printing -w, --writes number of max outstanding writes -W, --wait wait for W seconds for writes/reads to coplete
By default, the test will attempt to write to disk 100000 times using 16 AIO's, 1024 bytes per write to a single file. The command line would look like this:
./aio_test -l 1024 -w 16 -t 100000 -f 1
Example output looks like this:
Results
Errors (write fails + out. req's): 0 Maximum Write Time: 20.25 ms Minimum Write Time: 0.02 ms Average Time Per Write: 0.7388 ms
Total Time: 5.505 seconds. Total Written: 102.40 mbytes Average Writes/Second: 18166.23 (Write Size: 1024 bytes) Average Throughput/Second: 18.60 mbytes
More advanced options for this test are the concepts of batching and pooling.
Since the test allows multiple AIO attempts to multiple files, pooling ensures that the same AIO attempts are always attempted to the same FD. This creates a more realistic test scenario with regard to how AIO is typically used within an application.
Batching allows multiple writes to batch up in the pool in the event that all AIO's are currently used up, which can increase throughput for bursts of small amount of data being attempted.