7. gc-hosttraffictest

This tool tests the data transfer between the host machine and the IPUs (in both directions).

To use it, run:

gc-hosttraffictest -d {device_id} -j

where {device_id} is the id number returned by the gc-inventory tool.

If JSON output is selected, the output will look something like this:

 {
   "repeat_0": {
       "tile_to_host": {
           "duration_sec": "2.8448334399999999",
           "kbytes_transferred": "12800000",
           "gbytes_transferred": "12.20703125",
           "gbps": "36.858959306946282"
       },
       "host_to_tile": {
           "duration_sec": "2.0582515429999999",
           "kbytes_transferred": "12800000",
           "gbytes_transferred": "12.20703125",
           "gbps": "50.944987922693372"
       }
   }
}

The output will be plain text if the -j option is not specified. For example:

$ gc-hosttraffictest --device 0
Running test 1/1
tile -> host: 12.2070 GiB in 2.84 seconds, 4.29 GiB/s, 36.87 Gbps
host -> tile: 12.2070 GiB in 2.07 seconds, 5.91 GiB/s, 50.72 Gbps

If an error occurs during the test, then gc-hosttraffictest will return a non-zero exit code, and output an error message to the terminal.

7.1. Usage

7.1.1. Allowed options

`-j, --json-output`	Emit JSON output
`-d {id}, --device-id {id}`	Device id
`-n {arg}, --num-tiles {arg}`	Number of tiles: 1 to 32 (default: 32)
`-m {arg}, --mode {arg}`	r\|w\|rw\|cc (default: rw)
`-p {arg}, --payload-blocks {arg}`	Number of 64 byte blocks per transfer: 2\|4 (default: 4)
`-i {arg}, --iterations {arg}`	Number of 4KB transfers per tile (default: 100000)
`--min-ipu-host-bandwidth {arg}`	Minimum bandwidth (Gbps) IPU to host expected - fails if not reached
`--min-host-ipu-bandwidth {arg}`	Minimum bandwidth (Gbps) host to IPU expected - fails if not reached
`-v, --verbose`	Verbose output
`-h, --help`	Produce help message
`--version`	Version number
`-r, --remote-buffers`	Use remote buffers
`-R {arg}, --repeat {arg}`	Number of times to repeat test (default: 1)