The Exact Capture application supports a number of configuration options in both short and long form. For example:
$ exact-capture -i exanic0:0 --log-report-int 10 ....
A quick start guide is available for getting started. The following table lists all commands available:
|i||input||(required)||The ExaNIC interface(s) to capture on|
|o||output||(required)||The destination directory and filename stub to output to. Filenames will be output in the following format /output/dir/base_xx.expcap. Where xx is a unique file index. For details on the expcap format please see the Exact Capture Output Format (expcap) section later in this document.|
The list of CPUs to assign threads to for management, listening and writing threads.
This is specified in the the following format,
|s||snaplen||2048B||In some cases it is not necessary / useful to capture the entire packet. Set the snap length to determine the maximum size of packet that can be captured. This value cannot be 0 or less.|
|m||maxfile||0 (unlimited)||High rate capture can produce very large file sizes. To reduce the file sizes, Exact Capture can cap the file size to a maximum, and will start a new file each time it is reached. A value of 0 or less puts no limit on the output file size.|
|l||logfile||(none)||Exact capture can optionally write log messages to a log file specified.|
|t||log-report-int||1.0||This sets the statistics calculation and logging interval in seconds.|
|v||verbose||(flag)||Enabling verbose mode will produce 2 output log lines every log interval (see above). These log lines will include summary statistics of the performance of all listener threads and all writer threads.|
Enabling more verbose mode will produce 1 output log line for every listener and writer thread.
Each log line will include per-thread statistics counters/statistics.
This can be combined with
|d||debug-logging||(flag)||Debug logging mode enables display of the full file path, process ID and thread ID in each output log line. This is useful to track where a given log message originated.|
|T||no-log-ts||(flag)||By default, logs include a timestamp. This can make the output overly verbose. Use this flag to disable timestamps.|
|w||no-warn-overflow||(flag)||Software overflows will produce a warning. This may be problematic if the system is underperforming and these happen often. The flag disables these warnings.|
|S||no-spin||(flag)||By default Exact Capture outputs a progress “spinner” to the console. This flag disables it.|
|n||no-promisc||(flag)||By default Exact Capture puts the NIC into promiscuous mode. This flag disables it.|
Exact Capture supports several performance testing modes.
These can be used to give a sense of the best possible performance that you can expect from your system configuration.
The modes are as follows: